Help with electric car conversion! - Page 1
Forum section: electronics / projects

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 02:23:17 pm
content: So i am trying to build a electric carfrom a Fiat uno and i am thinking of buying 3x36v 1kwmotor out of ebay since thats all i can afforde cuz itsfree shipping.Would that be enought to move the car?

author: LeChatNoir
author_rank: Contributor
timestamp: May 10, 2015, 03:11:58 pm
content: Well depending on the model of Fiat Uni the stock engine is in the range of 33kW to 87kW.I have no experience in this but I dought anything below 15-25kW would be suitable.Don't forget $10,000 - $30,000 (if brand new) of batteries to power it and that added weight, could be less or more depending on what you are trying to do.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 03:15:44 pm
content: Quote from: LeChatNoir on May 10, 2015, 03:11:58 pmI am gettin one for about 150$ deppend either diesel or petrol.And as for batteris i can get 2pc for 50$ used and they go good for 5 years more then enought i just want to mnow would they be enought to get it moving of curse with the transmision.

author: rob77
author_rank: Super Contributor
timestamp: May 10, 2015, 03:42:26 pm
content: the petrol engine has it maximum power at high RPM, at low RPM the petrol engine really sucks - and exactly on those low RPMs is the engine used. 50kW @ 5000rom engine might easilly be a 5kW @ 1500rpmit's common to use a electric motor with power rating which is only a fraction of the original petrol engine. but 1kW is not enough for a small car - i would go for something in the 4-10kW range for such a small car as UNO.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 03:54:48 pm
content: Quote from: rob77 on May 10, 2015, 03:42:26 pmI said 3 1kw or maybe 4 depends since i cant soruce any big motor .but i dont want to go more then 30km/h

author: eneuro
author_rank: Super Contributor
timestamp: May 10, 2015, 04:15:51 pm
content: Quote from: Isad on May 10, 2015, 02:23:17 pmWhat are your speed and acceleration requirements and expected total mass?Some kind of optimisation needed to find best solution.Fiat Uno has not great aerodynamics, so remebrer that power needed to keep speed 70km/h will be close to ~3 x times (2.7x) higher than driving at 50km/h, while this power is propotional to ~V^3 (speed to the power of three)From time to time testing classic car driving @ 50km/h at outside city trips while preparing for longer electric vehicle journey and what can I say-it is difficult, while at narrow streets without highways between small cities there are often many trucks which ignore of course those 60km/h speed limits and worse they sometimes try to make signals that you should drive faster, so driving at those economic speeds (I mean low RPM low power diesel engine) is a challenge, but it is doable with additional equipment like additional banners on the car and monitoring system installed at front at back to show donks which try to press you to go faster while you do not have to because of it is not highway with 100km/h minimum speed, but local road with ~50km/h limitConclusion is-it is possible to drive at 50km/h at my local area, so power requirements for electic vehicle can be reduced-how much it will depend on EV aerodynamics and weather conditions, while winter days can be a challenge and difficult roads with snow-additional power needed, worse bettry working condition (preheting and temperature control mich be helpfull), etc...There are many factors which will affect EV needed power requirements, so without detailed driving requirements it is only guessing what you meant-how much power I need. My answer is it depends for reasons aboveQuote from: Isad on May 10, 2015, 03:54:48 pmUps, so this will be rather electric bicycle not EV and difficult to explaint other cars members on the road such low speed unless you add at back safety triangle meaning car failure or damage and emergency driving

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 04:24:49 pm
content: Quote from: eneuro on May 10, 2015, 04:15:51 pmOk so those are good questionquestion.I dont intend to use that thing for anything else thencity driving and my city is justa huge as field with no road that require brutal force so mainly its gona be city driven or max its gona go to the lake wich is like 20 min away from the city so yeah i dont intend to use it for a lot max its gona do is drive my father to his job wich is like 10 min away and maybe the max speed i would like would be 70km/h but thats never gona happen.Total mass maybe 2 people 3 max so total would go to 900kg.

author: mtdoc
author_rank: Super Contributor
timestamp: May 10, 2015, 04:26:27 pm
content: Quote from: Isad on May 10, 2015, 02:23:17 pmSure, as long as you're going downhill, .... And with a tailwind..Seriously though, as others have said, you'll need a bigger motor.For reference, i have a 1 kW motor on my electric bicycle and I just bought a used lawn tractor (ride on top lawn mower) without an engine that i plan to put a 10 kW electric motor in - which is standard for that type of conversion.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 04:28:13 pm
content: Quote from: mtdoc on May 10, 2015, 04:26:27 pmI wish i had anything to buy here if u wana get anything seruisu either pop 500$ or you go home.

author: mtdoc
author_rank: Super Contributor
timestamp: May 10, 2015, 04:37:17 pm
content: You might want to see if you can find a used forklift motor.

author: SL4P
author_rank: Super Contributor
timestamp: May 10, 2015, 04:39:54 pm
content: Motor(s)BatteriesESCBrakesSuspensionInsurance

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 04:40:52 pm
content: Quote from: mtdoc on May 10, 2015, 04:37:17 pmThats what i was talking 500$ lol cray cray.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 04:42:05 pm
content: Quote from: SL4P on May 10, 2015, 04:39:54 pmInsurace rip u can register that thing here assomthing that doesnt need any type of paper just a paper that u are abble to drive it.

author: DanielS
author_rank: Frequent Contributor
timestamp: May 10, 2015, 04:52:05 pm
content: If you are only going to put 3kW into an electrical vehicle, your acceleration is going to be worse than a bicycle: you are accelerating over 10X as much mass with about 1/12th as much power.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 04:59:11 pm
content: Quote from: DanielS on May 10, 2015, 04:52:05 pmFrom what i am hearing here it seems like i can forget evrything i cant finde any motor that is cheaper then 200$on ebay and there is no local dc motor seller the only one is ina 2h drive and they sell them for crazy amounts of money.I really thank evryone who tryed to help me but it turns out i just cant build it.Was gona be a nice summer building that well.

author: eneuro
author_rank: Super Contributor
timestamp: May 10, 2015, 05:16:04 pm
content: Quote from: DanielS on May 10, 2015, 04:52:05 pmCommon, if we take acceleration from 0km/h-30km/h only, than assuming 100kg bicycle with atlete riding it (power 250W) we need ~3.5kJ kinetic energy at 30km/h for bike, so looks like ~14sWhen we do the same for 1000kg EV 3kW power available we get... ~12s, so very close when forget about other factors and assume only kinetic energy changes.Probably the bigger issue than slow acceleration could be terrain slopes, so for such low power EV at 1000kg mass journey should be carefully designed and tested alse on ecould end its EV trip at the bottom of the hill depending on motors gears used, while slope will require more power than usual flat driving-gravity energy changes and each 1 meter is 1000*9.81*1m~10kJ which is ~1/3 of its kinetic energy ~35kJ at 30km/hIn comparision fo 50km/h we need 100kJ to achieve such speed, so easy to imagine than in float terrain road if we keep this speed only aerodynamic and friction to overcome, but slopes... is different story and hill are easier to go down hill than reverse

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 05:27:16 pm
content: Quote from: eneuro on May 10, 2015, 05:16:04 pmAnd thats why i hate physic lol.So your saying it can be done for 30km/h.But for 70km/h its another story how much force would that need.

author: calexanian
author_rank: Super Contributor
timestamp: May 10, 2015, 05:39:42 pm
content: General rule of thumb is 1KW per the effect of 1HP gas engine. This is a bit subjective because the difference in how it is applied mechanically and the torque power band of any particular motor, etc etc, but its close enough as a general rule. Your typical golf cart is at a minimum 5KW and most are in the 7KW to 12KW range. How well would you expect a leaf blower (About 1 HP) to move a Fiat? With enough gear reduction a mouse can move a house, but its going to take a while.

author: Zero999
author_rank: Super Contributor
timestamp: May 10, 2015, 05:40:27 pm
content: Quote from: eneuro on May 10, 2015, 05:16:04 pmAthletes can output considerably more power than 250W in short bursts. I'm not a trained athlete but I'm reasonably fit and can probably output more than 250W for a short period of time.

author: rob77
author_rank: Super Contributor
timestamp: May 10, 2015, 05:53:53 pm
content: Quote from: DanielS on May 10, 2015, 04:52:05 pmdont forget - if it's 3kW continuous , then you can easily overload it to 30kW for few seconds - and few seconds is enough for acceleration. - that's the yet another reason why the electric motor is rated at the fraction of the petrol : 3kW electric which can be heavilly overloaded to even 30kW (short term) and has the maximum torque from 0 RPM (3 phase squirrel cage motor with inverter) vs. the 30kW petrol which yields only 3kW at low RPM and the torque really really sucks at low RPM.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 06:22:59 pm
content: So in short tearms i can forget anything if i dont have at leasta 7kw motor?

author: eneuro
author_rank: Super Contributor
timestamp: May 10, 2015, 07:52:48 pm
content: Quote from: Isad on May 10, 2015, 05:27:16 pmI didn't said that, while I never saw your roads, but in the case where I've in my area well know trips in the range of 15km away and registered it with GPS than added height information from maps and while I know it is low trafic there, so low speed is not a problem I can optimise EV wehicle to this road, while there is no need for huge battery pack, I know exactly how energy requirements changes each few meters, so assuming constant speed and not to many breaking and accelerations all it is about math to estimate energy needed, makeing a few experimental trips, register data-how much energy was needed, but with understanding why it was lower or higer power consumption-I knoe I do not need Te$la to driveQuote from: rob77 on May 10, 2015, 05:53:53 pmFor a few seconds acceleartion maybe, but traveling througth long hill at quite high slope a few seconds might be not enougth to provide required energy needed to keep going at constant given speed, while gravity energy need will increase too high with rising slope and we will have to slow down

author: DanielS
author_rank: Frequent Contributor
timestamp: May 10, 2015, 10:13:40 pm
content: Quote from: Hero999 on May 10, 2015, 05:40:27 pmSame here. There was a pedal-powered dynamo-meter at a science fair a few years ago and I managed to hold about 700W for 10-15 seconds. This was on a horizontal setup, so no "cheating" using gravity assist. I could probably have gone 100-200W higher on a vertical setup with adjustable gear ratios or resistance. At a more cruise-like effort level, I was around 400W.

author: rob77
author_rank: Super Contributor
timestamp: May 11, 2015, 04:52:01 am
content: Quote from: eneuro on May 10, 2015, 07:52:48 pmthose conversions are for flat-lands onlynot just because of power, but also because of bateries. it's rare to see a conversion with a battery bigger than 10kW/h (usually less than that) - and that's only enough for a short daily commute on a flatlandi think such a conversion only makes sense for someone living on a remote "flatland" location with his own solar for charging the vehicle.

author: Isad
author_rank: Frequent Contributor
timestamp: May 11, 2015, 05:38:43 am
content: I am in a flat land there are no hillsand i only gona be using it in the city.

author: Isad
author_rank: Frequent Contributor
timestamp: May 11, 2015, 06:25:49 am
content: And btw i am gona be ussing the gears of the fiat soWouldnt that easy the job of the motor.

author: kjs
author_rank: Regular Contributor
timestamp: May 11, 2015, 06:40:14 am
content: the gear box will eat half of your available power. Electric motors don't need the a reduction as they have the highest torque at 0 RPM.

author: Isad
author_rank: Frequent Contributor
timestamp: May 11, 2015, 06:46:14 am
content: Quote from: kjs on May 11, 2015, 06:40:14 amSo no gear box but my question is i cant use 1kw motor likeuse 2 for the back drive cuz they arent that good so what do i do i cant source huge motor or even if i can its beyond my budged.

author: kjs
author_rank: Regular Contributor
timestamp: May 11, 2015, 07:09:27 am
content: sounds like a catch 22 but with 2-3kW you won't move much. Not even such a tiny car as an UNO.......

author: Isad
author_rank: Frequent Contributor
timestamp: May 11, 2015, 07:16:34 am
content: Quote from: kjs on May 11, 2015, 07:09:27 amWell it kinda is since anything above that cost more then 200$ for 1 wich i dont think of buying i have heard u can get a forklift motor for about 80$ well i am no finding one.

author: kjs
author_rank: Regular Contributor
timestamp: May 11, 2015, 07:20:21 am
content: just be patient, usually you find stuff a while after you have given up.........

author: Isad
author_rank: Frequent Contributor
timestamp: May 11, 2015, 07:34:07 am
content: Quote from: kjs on May 11, 2015, 07:20:21 amLol usally what happens all the time.

author: eneuro
author_rank: Super Contributor
timestamp: May 11, 2015, 11:17:54 am
content: Quote from: rob77 on May 11, 2015, 04:52:01 amHere go, a little bit research on... youtube and we found a way to decrease tires friction, by... applying bicycle wheel to a carHowever I do not recoment this, just watch for fun or skip to 7:00 time where it movesWow, what ais there and youtube pay$ for videos like this this ?

author: Isad
author_rank: Frequent Contributor
timestamp: May 11, 2015, 01:48:45 pm
content: Quote from: eneuro on May 11, 2015, 11:17:54 amThat would just be nuts changing from thick metal totthin.I wouldnt even try that.

author: rob77
author_rank: Super Contributor
timestamp: May 11, 2015, 06:11:37 pm
content: Quote from: eneuro on May 11, 2015, 11:17:54 ambecause one facepalm is not enough for those guys... they would deserve a movie made about them.. the title could be "dubm, dumber, dumbest and then that guy with the bicycle wheel"he was wondering about the failure point - it's easy - that wheel will fail during rapid deceleration, just hit the brakes @ 50 km/h and it will go to pieces.

author: SeanB
author_rank: Super Contributor
timestamp: May 11, 2015, 06:34:10 pm
content: Rolls Royce used somewhat more robust bicycle wheels for decades, they just were rather larger, somewhat stiffer and the power rating was "adequate". My father had a neat little sideline in the 1960's balancing them and putting on tyres. He was a lot faster than the method many owners in "Darkest Africa" used, of having 4 sets of wheels and tyres, and simply sending the worn set, along with a cheque drawn on Barclays Colonial and Overseas Bank, to Solihull, and wait 6 months for the 5 tyres and rims to come back in the crate. He got this by accident one day when a Silver Ghost pulled in with a flat tyre, and he balanced it as well after doing a patch and tube repair, as it was out of balance. Then he did the rest, and after that word got around....

author: Isad
author_rank: Frequent Contributor
timestamp: May 11, 2015, 07:12:12 pm
content: Ok guys so one last questionif i have the fiat uno and i put 2 motor 1 in eachtire so basically its has 2 tires pushing how muchpower would i need the motor to be so the car can moveabout 50km/h.

author: LeChatNoir
author_rank: Contributor
timestamp: May 12, 2015, 01:37:29 pm
content: You forgot time in that number, as long as the motors are capable of overcoming the standing friction and the air friction at 50km/h any size motor would do, so the question becomes how much power do I need to accelerate from 'a' km/h to 'b' km/h in 'c' seconds.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 12, 2015, 02:09:20 pm
content: Quote from: Isad on May 11, 2015, 07:12:12 pmfundamental mechanics for engineers... if you do like this, only takes 10 minutes...this has to be a lot of assumptions, friction, wind drag, electrical and all losses are lumped in the 50% loss. only on flat terrain and rigid bodies..

author: LeChatNoir
author_rank: Contributor
timestamp: May 12, 2015, 02:13:59 pm
content: Lets do some _crude_ calcs.Parametersweight = 1,000 kg wet weight, (batteries, people, motors, cargo)start = 0 km/h, (start speed)end = 50 km/h, (end speed)time = 20 secondseff = 75%, (efficient in transferring electricity to vehicle momentum)qty = 2, (number of motors)convert "start" and "end" to m/sstart = start / 3.6 = 0 m/send = end / 3.6 = 13.8 m/sstartJoule = 0.5 * weight * start^2 = 0 JendJoule = 0.5 * weight * end^2 = 96,450 JaddedEnergy = endJoule - startJoule = 96,450 JwattTotal = (addedEnergy / time) / (eff / 100) = 6,430 WwattMotor = wattTotal / qty = 3,215 WSo now we have the energy required to accelerate the mass to the desired speed.Add on to that number the air resistance at the desired speed in watt (joule/sec) and you have your motor power.This is assuming flat ground.And it seems I was beaten to it, mine doesn't have required torque though.Might as well throw in torque as well.radius = 0.3 m, (radius of driven wheels)rps = end(m/s) / (2 * PI * radius) = 7.368 rotation per secondangularMomentum = 2 * PI * rps = 46.29torqueMotor = (motorWatt * eff / 100) / angularMomentum = 52.08 NmSo 2 electric motors (if direct driven) each3,215 W52.08 Nm @ 442 rpm

author: eneuro
author_rank: Super Contributor
timestamp: May 12, 2015, 05:06:39 pm
content: Quote from: LeChatNoir on May 12, 2015, 01:37:29 pmNope, air friction can have huge impact on needed power and not any size motor would dohttp://hyperphysics.phy-astr.gsu.edu/hbase/airfri.htmlhttp://en.wikipedia.org/wiki/Drag_%28physics%29#PowerThe power required to overcome the aerodynamic drag is given by:P_d = \mathbf{F}_d \cdot \mathbf{v} = \tfrac12 \rho v^3 A C_dA car cruising on a highway at 50 mph (80 km/h) may requireonly 10 horsepower(7.5 kW) to overcome air dragWhile we know that power needed to push an object through a fluid increases as the cube of the velocity, than if at 80km/h ~22m/s we need for car 7.5kW, than at 50 km/h~14m/s we have ~1/4 of this power needed, so we need ~1.9kW, and this is not doable for any size motor but only for air drag it should have power>2kW, while it will never run at 100% efficiencyUsing this formula above it leads to estimated power for air friction overcome fromwikidata:7500W/(22.2)^3*V^3 -> Pa~0.685*V^3 , where V is car speed in m/sSo,Pa~0.7*V^3, but we have to remember that aerodynamics shape can affect this power needed and at bicycle we'll get very high power losess to overcome air friction.But back to topic and 50km/h it looks that this formula works while we have than easy estimation of this power needed to fight with wind and we get this what I've wrote above while did in the same way:0.7*(14m/s)^3= 1.9kWIn comparision for30km/h~8.3m/s we get: 8.3×8.3×8.3×0.7~0.4 kWONLY, or it can be so much for average human riding bicycle at recreational level, that when we divide this by 2 (I assume smaller air impact area ) than we get ~200W, so non profesional bicycle riders will not be able keep going even at such low speed for a long time, but those estimations are within intuitive range, so if someone knows simpler rule to estimate car power needed to overcome air friction let know.For me this derived rule:Pairforce= 0.7*V^3looks fine

author: mzzj
author_rank: Super Contributor
timestamp: May 12, 2015, 05:48:18 pm
content: Quote from: eneuro on May 12, 2015, 05:06:39 pmAnd you need to double that power fiqure to overcome tyre rolling resistance. Depending on exact aerodynamics, weight and tires the rolling resistance is bigger than air friction resistance in most mid-sized sedans up to about 60km/h or so. For a small but heavy fiat (batteries!) the rolling resistance is probably bigger factor.4kW truck motor or 2x2kW motors would be probably enough for 50km/h and you get at least 5x the rated power in short accelerations.

author: Isad
author_rank: Frequent Contributor
timestamp: May 12, 2015, 07:04:19 pm
content: Quote from: mzzj on May 12, 2015, 05:48:18 pmOk this looks pretty nice so 2kw motor should be enought i might even see if i can get 2x4kw will see.Thanks for the help evryone.Really appriciate it.This will be a nice summer.

author: eneuro
author_rank: Super Contributor
timestamp: May 12, 2015, 08:10:26 pm
content: Quote from: mzzj on May 12, 2015, 05:48:18 pmFirst google search for 4kW AC gives something like this:AC motor 48v 4kw electric car motor kit for electric golf cartI'm thinking on Peugeot 206 conversion in the future, but if gearbox will survive I'd rather tried AC motor connected in place of removed HDI 1.4 diesel, but at average 50km/h probably I have diesel consumption <<4L/100km, so it will be difficult to make decent conversion to EV classic car, but for sure no plans to buy another brand new ICE.@Isad Anyway, you'll have spare petrol engine cooling fan system ready to reuse in EV, so install with AC motor like shown in link above or more powerfull, add custom liquid cooling to this AC motor and you will be able get quite safe much more power if really needed.BTW: If you convert Fiat Uno to EV or now register your track using GPS logger, than you can send me for analysis, while testing software which estimates energy usage based on GPS data with applied terrain road height (altitude)

author: tautech
author_rank: Super Contributor
timestamp: May 12, 2015, 08:28:47 pm
content: Here's 2 links to a project here in NZ. Bit short on tech data, but shows you what's possible.http://www.nzherald.co.nz/motoring/news/article.cfm?c_id=9&objectid=11443751http://tsrmotors.co.nz/electric-car-conversions/

author: mtdoc
author_rank: Super Contributor
timestamp: May 12, 2015, 08:51:14 pm
content: Quote from: tautech on May 12, 2015, 08:28:47 pmGreat link! I love the dash mount multimeter for an instrument panel!Isad - I could be wrong but I don't think 4kW of motor will be enough -despite the calculations. As they say "in theory there is no difference between theory and practice, but in practice...."

author: Isad
author_rank: Frequent Contributor
timestamp: May 12, 2015, 08:52:06 pm
content: Quote from: eneuro on May 12, 2015, 08:10:26 pmI dont like AC motor that much they cost more then the normal brushed onebut they have they advanteg and as a 17 year old that i am surcing 300$ isnt easyhere in my country..Thats why i was after 2kw motors.

author: mtdoc
author_rank: Super Contributor
timestamp: May 12, 2015, 08:58:31 pm
content: FWIW,here is the motorthat I plan to put in my converted lawn tractor which is much smaller and lighter than a Fiat Uno. And I only plan to move at 10 km/h maximum.

author: eneuro
author_rank: Super Contributor
timestamp: May 12, 2015, 09:12:21 pm
content: Quote from: mtdoc on May 12, 2015, 08:51:14 pmYep, but it is interesting what it does? maybe battery voltage, 52 12V bateries andbloody electric carwinsBTW: In ICE converted car motor is not the only thing which will want electricity-remember about safety first, so ensure your breaks will work, because of Fred Flinstone driving style is probably prohibited in your country too

author: Isad
author_rank: Frequent Contributor
timestamp: May 12, 2015, 09:21:42 pm
content: Quote from: mtdoc on May 12, 2015, 08:58:31 pmOh well that would be nice having 2 of them one in each rear tire wouldwork well but dam 500$.

author: Isad
author_rank: Frequent Contributor
timestamp: May 12, 2015, 09:23:44 pm
content: 10/10 for the 700V 1000A car lol yeah its nearly faster then a V8but electricity can kick u in the but very hard lol wouldnt trust that carthat much imagine somthing would go wrong 1000A can make a huge holein the metal.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 12, 2015, 09:58:07 pm
content: Quote from: Isad on May 12, 2015, 09:21:42 pmyou havent think of gearing, mounting, coupling, machining cost etc, let alone the 52x12V batteries, how about..... simply forget it. or fishing is a cheaper hobby... or download that subaru car video and watch it over and over until you find something else better to do...

author: eneuro
author_rank: Super Contributor
timestamp: May 12, 2015, 11:03:19 pm
content: Quote from: mtdoc on May 12, 2015, 08:58:31 pmIf we'are talking about lawn tractors, I'd rather go into something bigger than those small robots below and with additional remote control, because of when we add human weight to those toys for big boys, than of course we need much more power to drive this thing and for me not too much fun ride noisy lawn tractors, so it will be interesting define working area of lawn robot (I've have slightly different concept while it have to work in more challenging environment) and let it go and enjoy walk with my dog and only from time to time check work progress in my yard

author: tautech
author_rank: Super Contributor
timestamp: May 12, 2015, 11:23:42 pm
content: Quote from: Isad on May 12, 2015, 09:23:44 pmYeah, but the same applies for most hybrids.But think about stopping such a beast with 1000 Kg of batteries on board.

author: Isad
author_rank: Frequent Contributor
timestamp: May 13, 2015, 05:41:38 am
content: Quote from: Mechatrommer on May 12, 2015, 09:58:07 pmI dont have a problem about mechanical stuf.My father worked as a mechanic and he has quite a lotof friend who can help me for nothing and machining ihave a uncel who does that.Batteris dont cost that much cuz i wasnt gona get 72pc thats why i was after 24-48v motors.

author: Isad
author_rank: Frequent Contributor
timestamp: May 13, 2015, 05:44:10 am
content: Quote from: tautech on May 12, 2015, 11:23:42 pmYeah but most hybrids have lithium like the Tesla car.They are all fully checked by a staff and have safty circuit all over the place .

author: G7PSK
author_rank: Super Contributor
timestamp: May 13, 2015, 08:31:40 am
content: Quote from: calexanian on May 10, 2015, 05:39:42 pmGeneral rule of thumb is 1Kw gives 1HP output on the shaft of an electric motor due to losses 9746 watt=1HP) for driving generators you need 1.5 HP per Kilo watt of generation with a diesel prime mover and 2 HP per kilo watt with a petrol prime mover. In real world you will find that due things like torque curve to drive machinery you will require five to ten times more horse power from an internal combustion engine than an electric motor.

author: LeChatNoir
author_rank: Contributor
timestamp: May 13, 2015, 02:26:44 pm
content: @eneuro I believe I said the standing frictionandthe air friction at 50km/h any motor would do, though my equations ignored those.For calculating the estimated air resistance if you just use basic shapes you tend to beveryfar off unfortunately.When cars are wind tunnel tested they get a number(several) you can punch in to figure roughly the expected resistance in this condition: still air, straight line, stp, ectBut since it isn't normally published and their are several models of this car that are different aerodynamically I didn't bother to search for it.Not that it would help too much because the electric conversion will change that number just from different weight and weight distribution.@mzzj I completely forgot the rolling resistance, that can get big quick, not only the vehicle but the surface will also effect it.Some "Contact Surface (Roll Coefficient)" (Crr), can't remember where I got this from...Asphalt (fair) 0.017Asphalt (good) 0.012Asphalt (poor) 0.022bicycle tire on asphalt road 0.004bicycle tire on concrete 0.002bicycle tire on rough paved road 0.008bicycle tire on wooden track 0.001car tire on loose sand (high) 0.4car tire on loose sand (low) 0.2car tire on loose sand (med) 0.3car tire on solid sand (high) 0.08car tire on solid sand (low) 0.04car tire on solid sand (med) 0.06car tires on tar or asphalt 0.03Concrete (fair) 0.015Concrete (good) 0.01Concrete (poor) 0.02Dirt (sandy) 0.037Dirt (smooth) 0.025dirty tram rails 0.005Grass (firm) 0.055Grass (soft) 0.075low resistance tubeless tires (high) 0.005low resistance tubeless tires (low) 0.002low resistance tubeless tires (med) 0.0035Macadam (fair) 0.022Macadam (good) 0.015Macadam (poor) 0.037Mud (firm) 0.037Mud (medium) 0.09Mud (soft) 0.15ordinary car tires on concrete (high) 0.015ordinary car tires on concrete (low) 0.01ordinary car tires on concrete (med) 0.0125railroad steel wheels on steel rails (high) 0.002railroad steel wheels on steel rails (low) 0.001railroad steel wheels on steel rails (med) 0.0015Sand (dune) 0.3Sand (firm) 0.06Sand (soft) 0.15Snow (2 inch) 0.025Snow (4 inch) 0.037truck tire on asphalt (high) 0.01truck tire on asphalt (low) 0.006truck tire on asphalt (med) 0.008

author: eneuro
author_rank: Super Contributor
timestamp: May 13, 2015, 08:12:16 pm
content: Quote from: LeChatNoir on May 13, 2015, 02:26:44 pmFromwikiand university we have:http://en.wikipedia.org/wiki/Rolling_resistanceSo, lets estimate power needed to overcome rolling resistance (drag):Frr= Crr*N, N=m*g -> Frr=Crr*m*gv=ds/dt -> ds=v*dtOut work to do while rolling: Wrr= Frr*ds -> Crr*m*g*v*dtSo, power needed is: Prr=dWrr/dt ->Prr= Crr*m*g*v,where g= 9.81 [m/s2] of course, so this increases linear with vehicle speedLets take 50 km/h and 1000kg vehicle on asphalt, so:Crr= 0.017v= 14 [m/s]m = 1000 kgPrr= 2.3 kWups:Quote from: mzzj on May 12, 2015, 05:48:18 pmSeams you were right, but some roads might be more challenging than asphalt, so it is clear that needed power will be affected by many factors and road type and its quality of course mattersBTW: In comparision for 100kg bicycle @ 30km/h only ~30W

author: Isad
author_rank: Frequent Contributor
timestamp: May 13, 2015, 09:03:43 pm
content: Quote from: eneuro on May 13, 2015, 08:12:16 pmWell this tourns out to be quite much in my favoreseems like 4kw to 6 will be enough.

author: mikerj
author_rank: Super Contributor
timestamp: May 13, 2015, 09:13:03 pm
content: Quote from: Isad on May 13, 2015, 09:03:43 pmThis is on a completely flat surface, and is just the power required to overcome rolling resistance. Are there no hills at all in your country? Is there ever any wind?

author: Isad
author_rank: Frequent Contributor
timestamp: May 14, 2015, 05:31:36 am
content: Quote from: mikerj on May 13, 2015, 09:13:03 pmHills in the city no.I dont plan to use this car outside the city wind yeah but not that much there is like 1 month with some crazy wind then it passes.

author: tautech
author_rank: Super Contributor
timestamp: May 14, 2015, 07:56:34 am
content: Quote from: tautech on May 12, 2015, 08:28:47 pmQuote from: tautech on May 12, 2015, 11:23:42 pmWell apparently it has ONLY 350 Kg of batteries.Made our national news tonight:http://tvnz.co.nz/seven-sharp/makes-little-car-go-so-fast-video-63133124.50 min video

author: LeChatNoir
author_rank: Contributor
timestamp: May 14, 2015, 08:38:57 am
content: Found some what appear to be the values for air resistance for the Fiat Uno E5, no idea if that's the correct one but close enough +/- 25%,http://www.mayfco.com/dragcd~1.htmCd = 0.33 - 0.34m2 = 1.83It takes about 1,063 W at 50 km/h, add in a light headwind (Beaufort scale, 3, "Leaves rustle") it goes to 1,288 W.Did some grade calcs as well for about 1,362 W with a small 1% grade at 50 km/h.Totalling up:Rolling resistance = 2,315 WAir resistance + light headwind = 1,288 WGrade resistance = 1,362 W0-50km/h in 20 sec = 4,823 WWe get 9,788 W, but this includes accelerating up to 50 km/h.So dropping that we get a cruse power of 4,965 W.Probably don't want to run the electric motor more than 110% for 20 seconds so that gives us 8,898 W, ~9kW.But this is actual power doing work not including inefficiencies.Lets be conservative, 75% of the power ends up doing work in providing power, that gives us 11,864 W, ~12kW.And here's some charts for no other reason than driving into hurricane force winds at 100km/h.

author: Isad
author_rank: Frequent Contributor
timestamp: May 14, 2015, 09:40:03 am
content: Ok so i just found somthing usefull on google.Could i use car dynamo as a BLDC motor since i can surce them for nearly 20$1 and it would be nice but is there any controller for them out there.Just saw this video but this guy is runing them with hall effect sensori would like a simple one.

author: eneuro
author_rank: Super Contributor
timestamp: May 14, 2015, 01:01:07 pm
content: Quote from: LeChatNoir on May 14, 2015, 08:38:57 amhttp://www.mindat.org/glossary/grade_resistanceDefinition of grade resistanceThe force, due to gravity, that resists the movement of a vehicleup a slope.This means, that grade resistance will increase power needs when climbing a hills, but goind down the hill if we'll be able keep our cruise speed (not forced to brake, but use regenerative breaking to limit air resistance loses), than gravity will help us overcome air resistance and grade resistance power will be not needed, so that is why I decided to write software, which based on GPS data and added height values, estimates slopes, this way we can better analyse power requirements for EV, assuming will be able keep cruising speed which is very often possible while driving at relative small speed up to 50km/h, so more often other "fast cars" will have to slow down from their 80km/h-100km/h to 50km/h than we will have to stop etc, eg. bicycle is on the rodad and we have drop our speed to 20km/h...This is another benefit driving at lower average speed than road average-it is less energy needed to cruise speed changes, while we are closer to this road average speed or even slightly belowWe should calculate average grade resistance but remember to count ONLY when vehicle is moving up a slope and on negative slopes moving down we benefit from this.This is cleary visible in fuel consumption in ICE cars when driving hundreds km from flat river city to mountains, that way back saves me a lot of fuel, when we do not drive too fast, while at higher speeds air resustance make this difference more difficult to notice

author: Isad
author_rank: Frequent Contributor
timestamp: May 14, 2015, 06:34:14 pm
content: Quote from: Isad on May 14, 2015, 09:40:03 amWould this be even posibble since i saw a lot of videos but none of themsaid anything about torque i dont know how much it would give without halleffect sensor?

author: eneuro
author_rank: Super Contributor
timestamp: May 14, 2015, 07:27:18 pm
content: Quote from: Isad on May 14, 2015, 06:34:14 pmForget about alternators as EV motorsI use alternator with custom voltage regulator but only as smart alternative energy source powered by humans with alternator output power limited by MPU based on Hall current sensing with builtin RPM sensor, so it starts from lower RPM than oryginal voltage regulators made for ICE engines.

author: Isad
author_rank: Frequent Contributor
timestamp: May 14, 2015, 08:16:50 pm
content: Quote from: eneuro on May 14, 2015, 07:27:18 pmOk so back to basic brushed ones.

author: nuno
author_rank: Frequent Contributor
timestamp: May 14, 2015, 08:57:07 pm
content: The motors you want to use are weak for a car, but there are smaller vehicles, motorcycles with side cars, three wheel cars, ... you get the idea.

author: Isad
author_rank: Frequent Contributor
timestamp: May 14, 2015, 09:16:16 pm
content: Quote from: nuno on May 14, 2015, 08:57:07 pmSo your telling me just to build somthing other then a car.I am not gona forget about it that easy.I randomly saw a video 2 years agoand thats were it all started.Planed for a 1 yearthis project now that i am stuck in the motor part will probably take me another year to get themotor but i really want to do this.And prob next up this will be to put the fiat uno motor ina home made dune buggy car just for lols and try it out in the beach lol.Sorry if i have misunderstod you!

author: nuno
author_rank: Frequent Contributor
timestamp: May 14, 2015, 10:53:30 pm
content: You don't have to quit on your dream. But sometimes we need to get there by iterations. And it's actually not a bad thing, since we learn in the process, and get better prepared for the bigger model, and thus later making less or less costly mistakes. If you're going to be stopped for a year, what will you learn in practice, compared to developing, even if not your dream machine, an electric vehicle? These are things to consider too.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 15, 2015, 01:23:28 am
content: A bicycle would probably be your best bet for a first time EV (actually hybrid) conversion.

author: Isad
author_rank: Frequent Contributor
timestamp: May 15, 2015, 05:42:46 am
content: Yes i know we can learn more if we start from somthingsmall then make our way up but idont have any usage forelectric bicycle yes i could use it for somthing like when i goswiming in the river but i like to pedal there.Get a bit morewalthy.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 15, 2015, 05:49:17 am
content: Quote from: NiHaoMike on May 15, 2015, 01:23:28 amsmall racing gocart will be fun too no need to learn stabilizing inverted pendulum and safer if one hit one from the side... with overall target driver+cart weight of less than 100kg and some compromise to max acceleration, one can reduce motor power significantly... and use hybrid system (err with manual pedal) too please...

author: eneuro
author_rank: Super Contributor
timestamp: May 15, 2015, 06:52:25 am
content: Quote from: Mechatrommer on May 15, 2015, 05:49:17 amNot too much fun in a heavy rain with lighting or shortly after when other cars will blow road water-basicly you will not be able drive such thing on public road.The same riding an electric bicycle-huge air resistance power lossesVelomobile based EVs are much better choice, while they have great aerodynamics profile and with two humans in this configuration decent human peak powerMake quick calculation similar to those we've made above and you will quicly find that maybe you don't need electric motors with two people in such velomobile, which has very small air impact area and two people seating in vehicle axis share the same air hitting area

author: LeChatNoir
author_rank: Contributor
timestamp: May 15, 2015, 07:35:57 am
content: Velomobile, hmm.Lets see, a reasonable weight would be 50-60kg plus 2 riders(lets go heavy 80kg each), so ~220kg total.Cd of .27Frontal area ~0.45m2All weight supported on bike wheels on asphalt road, Crr0.004Ignore acceleration power and just calc cruze power at speeds.

author: Isad
author_rank: Frequent Contributor
timestamp: May 15, 2015, 07:45:51 am
content: Quote from: Mechatrommer on May 15, 2015, 05:49:17 amOk so you guys still dont understand me if i dont have a usage for a certen devicei am not so happy about building why would i need a electric go cart when i could wack in adisel generator engine and be happy.The car isnt gona be used by me it is for my father whotakes a 10min trip to work with a disel engien and even if he doesnt use it the car is quite nice thena bicycle or a go-kart.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 15, 2015, 08:25:09 am
content: but but... now u have 2 car right... one is the ol classic dizel 4 d ol man to work, one is to make him happy family during holiday... not much cost addition 4 2 mobiles aey?... still dreaming for d hybrid? You should start make a bom n costing then u can figure out the approx infenitesimal time when your dream comes true. Brilliant peoples (that dont require asking in forums) since long time have failed 2 realize many wonderful projects albeit everything design,bom,costing are completed... only left one thing, the lack of fund o budget thereof.

author: Isad
author_rank: Frequent Contributor
timestamp: May 15, 2015, 08:34:29 am
content: Quote from: Mechatrommer on May 15, 2015, 08:25:09 am2 cars what ? i have an old disel generator who need some work to get started i didnt say i have a car i meant i dontwant to build somthing i dont have a use for like the go kart why on earth would i need one.And budge yes i have a tight onethat why my uncle decided to help me with the metal work since he has works with that and has quite a lot of parts and themechanical side is gona be done by a friend of my father with no cost.If i had the money to build the car with all the parts new iwould do it but its not gona happen in a long time.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 15, 2015, 10:19:10 am
content: you already have dizel engine but you dont have 5kW motors. ok i get it, a dizel engine car... lets start again... how much HP of dizel power do you have?

author: Isad
author_rank: Frequent Contributor
timestamp: May 15, 2015, 10:22:26 am
content: Quote from: Mechatrommer on May 15, 2015, 10:19:10 amI have a dizel engine that i can get in a go cart but its not mine ok.Thats it i dont know how much power it has but judgingfrom the sice 6-10hp.

author: eneuro
author_rank: Super Contributor
timestamp: May 15, 2015, 02:18:24 pm
content: Quote from: LeChatNoir on May 15, 2015, 07:35:57 amYou should ignore gravity too since you don't know how flat is it and one can oscilate over negative slope and positive, so average will be 0%Anyway with 1kW motors support + humans power decent speeds and huge range.The only issues are safety, while so many donks on the roads, so being very low from ground increases probability to be serious hit in the case of accident, but on bicycle the same problems.However on roads with small amount of cars, free of tracks probability to be hit goes down, performance is not so bad when fight with air rsistance

author: LeChatNoir
author_rank: Contributor
timestamp: May 15, 2015, 04:05:15 pm
content: @eneuro I left in 1% grade uphill because it is very minor grade wise, 1 foot up per 100 feet travel so even on "flat" roads you could be doing that fairly often, since itcouldvery well be constant(long slight incline) you would need to consider that for sustained cruse power, else you might be finding onseeminglyflat terrain you are using more power(effort) than anticipated.Though for consumed power over a flat(equal up and down) distance you can drop grade resistance power consumption.As for acceleration if you can do a constant cruse at whatever speed, you should be able to output an increased amount of power in order to reach the cruising speed.That 50-60kg was for a lack of any electric assist or power, cowling's are heavy.., but adding a few kW and batteries is pretty light so it won't change much.A few kW might be a bit much, 1 or 2?, how many kW to wheely one of those things?Performance for energy in vs speed is great for this, but if it doesn't meet the use case or requirements it's only helpful in seeing other configurations in comparison to the expected use case, maybe helpful?Safety is always a problem in non-isolated|controlled environments, it tends to be what your willing to trade for, perceived or actual and how much effort|moneyyour willing to use to modify it.

author: Isad
author_rank: Frequent Contributor
timestamp: May 15, 2015, 04:34:19 pm
content: Ok so you guys are just blowing my minde.All of you know so much about physics andmeanwhile i am here like yeah totally..Btw from the comment in the top as howi can aforde a dizel engine and not a 5kwdc motor well dizel engine here cost nix tonothing i can get a 110 hp motor for about 200$but its the other way about dc motor.

author: eneuro
author_rank: Super Contributor
timestamp: May 15, 2015, 08:08:27 pm
content: Quote from: LeChatNoir on May 15, 2015, 04:05:15 pm1kW BLDC motors are not very expensive and price not too much higher than 750W or 500W, but if we have more than 1kW, lets say 3kW (3x1kW in each wheel), than if even when not used to drive at normal conditions, on strong down the hill with huge negative slopes we can use bigger motors as generators, so disipate this energy as a heat in power resistors (electromagnetic braking) or better try to put back to battery, while driving too fast down hill could be dangerous, so more powerfull motors doesn't mean they will be used only during acceleration, but as breaks too.When you calculate how much power is needed to disipate during braking, than for longer down hills more powerfull motors might be needed.220kg at 50km/h has kinetic energy 22kJ, so whem will try to slow down to 0km/h in a few seconds, lets say 10s (not emergency breaking), than we have power losses 2.2kW, so 1kW motor probably could do it for 10s, but 2kW motor looks better.Lets assume 1kW/100kg and probably it will be fine, so lets check it out , but I'd rather not go afster than 30km/h in vehicles liek those, while they are so quitet, that many people will have problem to notice them at higher speedIt is quite easy to scale needed power-invest into one rear motor first, than add another two if needed more power

author: Isad
author_rank: Frequent Contributor
timestamp: May 16, 2015, 06:16:20 pm
content: Ok guys so the car might take some time but until theni have decided i will build a electric bike well the problem isi dont want a huge motor neither a huge battery so wouldsome rc lipo and a esc and brushless rc motor do the job i dont wanta imdeate start i will pedal a bit and then turn on the motorto accelerate.SO my question is is there any motor that can dothat job cuz i know there are tons of esc but idk if there is a motoror if this thing will even be possible.

author: SL4P
author_rank: Super Contributor
timestamp: May 16, 2015, 10:13:02 pm
content: So my take on Thi - whether you want to take the advice or not is three major factors wgphich you are trying to ignore,,,SAFETYRELIABILITYUSABILITY&EVERYTHING ELSE

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 07:35:21 am
content: Here are a couple brushless rc motors, just grabbed the first bigger ones I found.http://www.hobbyking.com/hobbyking/store/__24853__Turnigy_AquaStar_T20_3T_730KV_1280KV_Water_Cooled_Brushless_Motor.htmlhttp://www.hobbyking.com/hobbyking/store/__47015__NTM_Rotor_Drive_600_Series_510KV_5500W_600_50_size_heli_.htmlin-runner: the case is immobile and the shaft turns.out-runner: the shaft is attached to the case and turns with it, immobile attachment point on one end of motor.The main problem with these types of motors is HEAT, the magnets are no longer magnets once they have been heated up past a certain temperature dependant on the specific magnets composition, the curie temp:http://www.magnetsales.com/neo/neoprops.htmThe more powerful the magnet for Neodymium magnets the lower the curie temp, higher grades are specified with a higher number N##, example N48 @ >80oC the magnets has been permanently destroyed and is a lump of magnets shaped metal.Now this isn't normally a problem with these two motors in their respectiveRCapplications:Thisin-runner is for a boat and normally has low(<20oC) temp water cooling it, since it is an open loop(it's a boat) the input water never heats up.Thisout-runner is for a helicopter or plane with the motor directly exposed to the air stream, a lot of air to cool it.Since the case temp will always, without an external heat source, be lower than the magnet temp, the case temp will be capped(don't go over) once the motor is in thermal equilibrium with the magnets somewhere below the curie temp.When the motor isn't in thermal equilibrium, the case temp doesn't tell you how hot the magnets are getting, you could do some calcs, find the magnet temp by looking at input heat, thermal capacity and thermal resistance(heating/cooling), to find how much power you can safely throw into it, until you reach thermal equilibrium.Your max case temp is limited by how much cooling you can provide.Oh, the RC ESC's are the same just with junction temp instead of curie temp, the max amp is spec'd with large cooling taken into account:passive air cooled(plane, heli)active air cooled(own fan & heatsink)active water cooled(boat have pumps)For the out-runner + passive ESC I would put a >100 CFM fan to it and with a cowling to route the air into it and out of it, put a big filter to keep out the crap(mud, leaves, sand, ect), big to avoid lowering air flow too much.The in-runner a water reservoir, pump and radiator+fan, monitor water temperature rise to see if the radiator is big enough.

author: eneuro
author_rank: Super Contributor
timestamp: May 17, 2015, 07:41:51 am
content: HPV doesn't need a motorI'll log today on GPS my 15km track to tennis court to optimize for EV-we'll see how energy requirements changes on this road

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 08:06:25 am
content: Quote from: LeChatNoir on May 17, 2015, 07:35:21 amOk so i looked up some motors to i found some great ones but simply the problem is that u finde the motor the esc and then the problem are the batterynormal lipo will have a 5Ah rating wih these motor draw about 20A min i mean the one i found and lipo really cost a bit to much.And i cant put a battery car in a bicycle.Now those motor (just asking and this might sound dumb) but they were about 5kw each so would 1 of those in 2 wheles of the fiat be enough to moveit or do they lack the torque.I dont anything about rc motor so excuse me .

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 09:22:06 am
content: A great thing about brushless motors is that, with the appropriate controller:At minimum rpm they output their maximum torque.At maximum rpm the maximum torque they are outputting is exactly what is needed to keep them turning at that rpm, ie they physically cannot go faster because of the back-emf caused by how the motors function is generating counter torque.Incidentally this is thekvrating: rpm = kv * VNTM Rotor Drive 600 Series 510KV / 5500W = 44.4v = 22,644 rpmTurnigy AquaStar T20 3T, Star wiring = 730kv @ 44.4v = 32,412 rpmTurnigy AquaStar T20 3T, Delta wiring = 1280kv @ 44.4v = 56,832 rpmNow with a load these motors will never reach that rpm and on some motors that speed is higher than the bearing speed which will burn the bearings out so a load is always needed to be connected on those ones.A lowerkvrating for the same Watt means better low speed torque and more efficient at low speed assuming equivalent efficiency curves.As for lipo's the Ah is the energy stored in the battery, the amps they are capable of of is theCrating times the Ah rating.So C * Ah = AmpRandom chosen:https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=495097.5 Ah2S (3.7*#), = 7.4v90 CSo the max amp that can be drawn is somewhere ~675 amp.note: some batteries are listed 2Cratings, a burst(short time) and continuous, make sure to check the continuous, sometimes they only list burst.The energy of a lipo is: Ah * V = WhWith the previous battery:7.5 * 7.4 = 55.5 Wh, @ 1kW = 3 minutes and 19.8 seconds.Another random battery:https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7409612 Ah6S, 22.2v10 CAmp: 120 amp.Energy: 266.4 Wh, @ 1 kW = 15 minutes and 59 secondsHere's the HobbyKing lipo filter:https://www.hobbyking.com/hobbyking/store/lithium_polymer_battery_configuration.aspRC lipo's are for high amounts of power in a small light weight package, not so much for low amounts for power but for long times, also in an electric bike you would only be using bursts for acceleration, < 40km/h you ain't going be needing much full time power.Now moving a car on RC motors, hmm.Gotta gear it right and with an appropriate kv rating.Also bear in mind this is the energyinto the motor not the energyoutof the motor, RC motors are generally not designed for efficiency so left say 85%.5.5kW * 85% = 4.675 kWWell the energy to move a Fiat Uno at 50 km/h cruse is about 5 kW, so you fall short with 1, using 2 you get around 9.35 kW which is enough for cruse and acceleration.Buuuuut, motor to wheel efficiency, what is that?Lets go blindingly naive, say 2 sprockets one directly onto the axial and one one the motor, motorbike roller chain,perfectlyaligned,clean,lubedcorrectly ~98%.9.35 * 9.35 kW = 9.163 kW, so yeah got enough when operating in motor efficient range.Probably need a support bearing on the motor shaft end with itperfectly alignedso you don't bend it.Reality is less than ideal, so how much much extra do you need?Try looking at the attached brushless curves.

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 09:33:41 am
content: So in short tearms yes you can do that but the motors shaft is to tiny.I will have to think a bit more about this.And about the batteryrs well howabout 100Ah car battery like 4 or 5 in paralel cuz lipo are to pricy.And btw is there any ESC that comes plug an play i just dont wantto program one and i dont know how to so yeah.

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 09:43:09 am
content: The shaft is small but the main problem is a bunch of unsupported length with a bunch of torque.100 Ah @ 12v, 5 qty.40-45km/h @ 5 kW cruse = 1 hour, 12 minutes, 51 km range, minus inefficiency.

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 09:47:42 am
content: ESC for RC are pretty plug and play, some of them you can buy a programming card to modify their settings, pretty simple, random example:http://www.hobbyking.com/hobbyking/store/__14631__Turnigy_TrackStar_ESC_Programing_Card.htmlWhat you need to do is drive the ESC with a pwm signal:0 pwm zero motor speed,100 pwn 100% motor speed(or at least trying to).

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 09:57:31 am
content: Quote from: LeChatNoir on May 17, 2015, 09:47:42 amOh wow that easy well seems like a pretty easy.About the pwm servo controller or arduino wich one is the best.And would car batterys work for these motor and wich one to goi know the one without water cooling is cheaper but the one with watercolingprobably does its job a bit better or can i simply air cool .

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 10:18:15 am
content: I just chose the first motors that showed up, you probably should compare more.I lean towards water cooling as the motor area is more compact and you can attach a large radiator easily so should be able to keep the cooling more reliable than air cooling the same amount, keep an eye on the fluid temp, try to keep it near ambient as possible.As for pwm either would work but since you are controlling the accelerator of a verydangerousobject, reliability and safety should be paramount.Servo controllers are more likely for that, also add in redundancies and a big manual cut off(sever) for the main power close to the driver in an instantly accessible place, big red button.Since you seem to not be confident in programming, I cannot suggest doing your own, though it would be good for doubly redundant pots on the accelerator with ratings >25m cycles and custom machine code just for the accelerators pwm, with redundancies and checks everywhere.Voltage, gotta be careful,nevergo over ESC's rating or even close, but the motor requires the max spec'd voltage at max power.edit:keep in the continuous amp for the batteries, it's quite bad when you melt/explode them, also hydrogen gas is produced and is explosive.Max voltage for lead acid batteries 14.7v?2 series = 29.4v3 S = 44.1v4S = 58.8vEven if it only for a moment going higher voltage than the ESC rating can and will destroy them.

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 10:28:20 am
content: Quote from: LeChatNoir on May 17, 2015, 10:18:15 amOk so thanks for the help yeah i have thought of a lot of thingis for safety .I am confident in programing i just dont like to do it i can learn it very fast sicne there arehundrets of videos out there.About the servo controllers dont they just use a 555.Likely a arduino would be much acurate .

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 10:38:55 am
content: Oh man i searched for 200A esc well that brings me back to were i was with theother motor this thing would still go over my budged.Hmmmmmm evrything hasto have a catch doesnt it the dc motor are over priced but the controllers are notnow on the brushless one there are the controller over priced and the motor not.

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 10:39:28 am
content: Because it is in regards to safety for things like modern cars accelerators each line of code will be checked and verified multiple times in the programming languageandin the outputted machine code, this is quite specialised and you would need to know perfectly how it is functioning hardware wise, going line by line in 100's or 1000's of line's verifying and checking.Yes, servo controllers used to be 555 but it's generally changed to microcontrollers, I suggested them because they would be simpler programmed and less likely to have some sort of error.

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 10:40:42 am
content: DC motors are easy, multiphase brushless, now that's harder.

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 10:45:15 am
content: Quote from: LeChatNoir on May 17, 2015, 10:40:42 amYes DC motor are easy but they arent ecaxtly cheap i wanted to put 2 motor arund 2-3kw in therear wheels tourns out in my country they are epxensive as hell and shipping from outside is the same.

author: nuno
author_rank: Frequent Contributor
timestamp: May 17, 2015, 12:13:45 pm
content: Typical RC ESCs like the ones on HK don't do current limiting, so they tend to blow up when used in big electric vehicle (human transportation). A propeller tends to be a constant load and never stalled, while in an EV the load range is huge and a motor stalled or almost stalled is normal. Also, be ware of the typical high rpm/V of plane/helicopter motors, as you will have to have a big mechanical reduction for them to be usable in big EV - usually you'll need a 2 stage reduction.What you want is one of these DC "scooter" motors, there are between 200W and some 1000W:https://www.google.pt/search?q=scooter+dc+motor&source=lnms&tbm=isch&sa=X&ei=aIVYVf-CIcSZgwSYvoHQCA&ved=0CAcQ_AUoAQ&biw=1218&bih=726Ready made controllers for this are cheap, or you can have fun developing your own.

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 12:36:07 pm
content: @nuno Good points, I forgot to mention sizing the controller to be capable to handling the full motor stall current, or measuring the current outside and modifying the pwm so the current is under control.Also try not to use a plane, heli or boat controller but some sort of vehicle one, only the vehicle ones handle going from stop and up smoothly and handle stalling better.

author: nuno
author_rank: Frequent Contributor
timestamp: May 17, 2015, 12:49:50 pm
content: Stall current in low voltage "big motors" (let's say 200W and above) is huge; I don't know of any controller that simply handles that current, not even for a 24V 200W DC motor. Usually current is measured and PWM duty cycle adjusted on a cycle-by-cycle basis to keep the motor current below a maximum.

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 01:25:07 pm
content: @nuno I was poorly worded, but that's the beauty of the more complicated controllers required for brushless motors, when starting if it was just brute forced, most controllers would burn out, but to get the rotor moving very low pwm is generated and once the controller sees the back-emf generated by the rotor moving one click(clogging torque) it knows the rotor position and starts using larger pwm cycles so it doesn't burn out.So the controller although doesn't measure the current it know how fast the rotor is moving and in what orientation the coils are to the magnets.It's also why I suggested vehicle controllers instead of air or boat, it handles starting a lot better since that is part of the primary used functions.If it was brute for example my 2665 W brushless I just grabbed from the shed has a DC resistance of <0.1 Ohm on each of the coils, with a rated 6S or 25.2v when batteries are charged, this would only current limit based on the batteries esr and the controllers, easy to burn out.Random, crudely measured the clogging torque on this at around 0.2 NmIt's this motor:http://www.hobbyking.com/hobbyking/store/__23521__NTM_Prop_Drive_50_60_Series_380KV_2665W.html

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 01:26:54 pm
content: Ahh, I only know this happens with higher amp motor controllers, don't know about lower ones.

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 03:22:33 pm
content: Quote from: nuno on May 17, 2015, 12:13:45 pmYes but from what i have heard here is you either need more then 4kw or it wont do anything usable.

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 03:27:37 pm
content: I believenunowas in reference to a bicycle motor, rather than a car motor.It's not so much as <4 kW won't do anything but you won't be able to reach the specified speed(50 km/h) with anything lower.

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 04:46:27 pm
content: Quote from: LeChatNoir on May 17, 2015, 03:27:37 pmA ok.But the only problem is i simply cant find any motor on ebay or anywere that is cheaper than 150$ withthat kw rating.

author: eneuro
author_rank: Super Contributor
timestamp: May 17, 2015, 05:58:22 pm
content: Quote from: LeChatNoir on May 17, 2015, 03:27:37 pmThey reach with human power only close to 80 km/h downhill and 50km/h very often while driving hundeds km within 20 hoursBTW: Tried log today nice 15km bicycle track wit a few hills, unfortunate bloody "smartphone" with flammable Li-on deplated and nasty WindowsCE software left 0 bytes NMEA GPS data fileI will have to connect next time this thing to 12V battery, but have another 120km track registered with car in both directions, so it will be interesting analysis howto manage EV speed to optimize for lowest possible energy usage

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 06:40:01 pm
content: @eneuro <4kw in regards to a Fiat UnoInteresting video, took me a while to realise the percentage was the grade, throwing somecrudeestimations and those numbers into the calcs these 2 people each seem to top out at around 375-400 W on a climb.Ahh lipo fires, that s**t is scary, when you breath that smoke in the gas converts to hydrochloric acid in your lungs, though you do have to abuse them rather a lot now days to get them to do that, in most cases....Also you cannot put out a lipo fire with a normal fire extinguisher, you need a class D fire extinguisher with it's category covering lipo's.

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 06:45:44 pm
content: Quote from: LeChatNoir on May 17, 2015, 06:40:01 pmWell throwing it in a lake would extinguishe it or is that thing that crazy.

author: nuno
author_rank: Frequent Contributor
timestamp: May 17, 2015, 07:13:45 pm
content: Yes TheBlackCat thank you, I was referring to the smaller vehicle alternative, not necessarily a bicycle, but hardly a full sized car (although 1KW in parallel or on each wheel would be 4KW total, but that complicates mechanics and control while still being far from optimum, and I doubt it would be much less than $200 even from China just for the 4 motors).

author: LeChatNoir
author_rank: Contributor
timestamp: May 17, 2015, 07:16:56 pm
content: Well, lipo stands for lithium polymer, pure lithium metal tends to be stored under oil so it doesn't react in contact with the moisture from the air, submerging lithium underwater in say, a lake while I dunno, on fire, would make the being on fire part that much more powerful.In lipo's the lithium is averythin sheet sandwiched between polymers and dielectrics, those things tend to retard the reaction a bit, but will add other nasty thing's to the smoke as they burn, since the fire is mainly the lithium then it would keep burning.Now is a lipo fire that crazy to throw in a lake, if you think of the effectively hydrochloric acid gas that thing produces as well as high temperature flames covering most of it plus that it would probably keep burning....So third degree burns and hydrochloric gas inhalation, hard to tell which would be the more expensive hospital bill the potential skin graphs or the inhalation treatment(more than just airways and lungs).

author: Isad
author_rank: Frequent Contributor
timestamp: May 17, 2015, 09:07:09 pm
content: You guys making me a bit consorned i was experimentingwith a laptop battery 1 year ago and well like a spoon that i am i acidentaly poured water on it that thing bursted into flames but didnt las long since it wasnt a big peace but stilli inhaled some fumes not mich but still some.Well i have inahled a lot of fumes from my experiment and still didnt have any problem

author: LeChatNoir
author_rank: Contributor
timestamp: May 18, 2015, 03:35:29 am
content: Hmm, guess you were lucky, there are some horror stories though.On contact with water|mosture|"what you are made of" HF (hydrogen fluoride) changes to Hydrofluoric acidhttp://en.wikipedia.org/wiki/Hydrofluoric_acid#Health_and_safetyfrom :http://www.rcgroups.com/forums/showthread.php?t=1142861post 6 : 18/05/2015"HF (hydrogen fluoride) gas can be emmitted from Lipo batteries during cumbustion. VERY VERY toxic esecially when exposed in high enough quantities. I work with HF in a laboratory and mere skin contact can couse severe organ and bone damage, and even death."from :http://www.bt.cdc.gov/agent/hydrofluoricacid/basics/facts.asp: 18/05/2015Immediate signs and symptoms of exposure to hydrogen fluorideSwallowing only a small amount of highly concentrated hydrogen fluoride will affect major internal organs and may be fatal.Hydrogen fluoride gas, even at low levels, can irritate the eyes, nose, and respiratory tract. Breathing in hydrogen fluoride at high levels or in combination with skin contact can cause death from an irregular heartbeat or from fluid buildup in the lungs.Even small splashes of high-concentration hydrogen fluoride products on the skin can be fatal. Skin contact with hydrogen fluoride may not cause immediate pain or visible skin damage(signs of exposure).Often, patients exposed to low concentrations of hydrogen fluoride on the skin do not show effects or experience pain immediately. And, severe pain at the exposure site may be the only symptom for several hours. Visible damage may not appear until 12 to 24 hours after the exposure.Depending on the concentration of the chemical and the length of time of exposure, skin contact with hydrogen fluoride may cause severe pain at the point of contact; a rash; and deep, slow-healing burns. Severe pain can occur even if no burns can be seen.Showing these signs and symptoms does not necessarily mean that a person has been exposed to hydrogen fluoride. Other chemicals also can cause these effects.Exposure to hydrogen fluoride can result in severe electrolyte problems.Long-term health effects of acute exposure to hydrogen fluoridePeople who survive after being severely injured by breathing in hydrogen fluoride may suffer lingering chronic lung disease.Skin damage caused by concentrated hydrogen fluoride may take a long time to heal and may result in severe scarring.Fingertip injuries from hydrogen fluoride may result in persistent pain, bone loss, and injury to the nail bed.Eye exposure to hydrogen fluoride may cause prolonged or permanent visual defects, blindness, or total destruction of the eye.Swallowing hydrogen fluoride can damage the esophagus and stomach. The damage may progress for several weeks, resulting in gradual and lingering narrowing of the esophagus.

author: Isad
author_rank: Frequent Contributor
timestamp: May 18, 2015, 04:00:42 am
content: Well thats one way to start the day know your goodfrom that chemical.I knowed lipo are crazy but thatthey are that much.Next time i need to be a lot morecareful i usally never worried about them.

author: eneuro
author_rank: Super Contributor
timestamp: May 18, 2015, 08:45:55 pm
content: Quote from: LeChatNoir on May 17, 2015, 06:40:01 pmMaybe, Cd used in your estimation is slightly higher than 0.20 available in some velomobile designs, while "velonaut" -I like this name for someone riding velomobile- quite easy had >60km/h at negative -5.5% downhill and than shortly this speed doesn't drop too much at 5% slope-velomobile kinetic energy helps him climb up the second hillNice roller coaster between hiils, so he must have low air resistance and probably lower Cd than 0.27 you have assumed in previous calculation.Anyway, I've nice 120km track with many hills up and down to optimise for EV. Trying now figure out energy requirements and make virtual rideJust testing software I've wrote in C++, which converts GPS NMEA log data records $GPGGA to ECEF XYZ absolute earth cartesian cordinates based on WGS-84 ellipsoid model.For the moment this small utility correctly converts GPS log files taken from wireless GPS device and I can display registered track in 3D with slopes cleary visible, however GPS altitude hasn't got great accuracy-I will try to recreate road in OpenGL based on this recorded data and try to make virtual ride to see how energy changes on approximated parametric XYZ trackThere are ~5000 GPS fixed points taken at average 70km/h car speed-I was trying to keep moving not faster and not slower to get equal distances between GPS 1second log points and to practice if I will be able ride this road at such quite low, but decent and probably maximum speed for my HPEV.BTW: I had already passed this 120km road on bicycle many years ago and what can I say-it wasn't easy, so it will be interesting to compare with HPEV riding the same track with very low air resistance and small electric motor support

author: eneuro
author_rank: Super Contributor
timestamp: May 21, 2015, 06:31:54 pm
content: What about reuse those probably not patented inventions made by those guys... riding railways in DIY human powered rail bicycle and.... skip too 5 minute.. it's worth to watch those mechanical inventions.. especially rail breaking systemI like inverted bicycle conceps and rare wheel changed to front wheelYep, all you need is catch train in those wehicles and.. ride for free

author: Isad
author_rank: Frequent Contributor
timestamp: May 21, 2015, 06:50:13 pm
content: Quote from: eneuro on May 21, 2015, 06:31:54 pmOh wow well thats the defeniton of stupid.Imagine a train comming in there faces.But proabably theyr using old railways since no train uses them in the Usa i bealive.

author: SeanB
author_rank: Super Contributor
timestamp: May 21, 2015, 07:18:32 pm
content: From the looks of the rail top it has not been used in a decade, desert environment means little rust, and the rust on the side of the rail, along with the fish plates and the wood sleepers and missing ties says this is an old mining railroad, no longer in use, and probably a century old. The brush growing in the ballast also says the same, if it was in regular use it would have shiny topping and no brush, cleaned off by the rail cars and the track maintenance crew.

author: eneuro
author_rank: Super Contributor
timestamp: May 21, 2015, 08:53:42 pm
content: Quote from: Isad on May 21, 2015, 06:50:13 pmIt looks like they know what they are doing and no electricity around, so a little chance to meet a train but some DIY vehiclesBicycle riding is much more dangerous, so think twice about riding electric oneWatch this donk at 1:494:04 is the best failHe falls from the bike celebrating finish and... tries to finght for first againNope, electric bicycle is something I've dismissed from my EV list at the begining for many reasons-people will not notice quiet bicycle-as we can see even human powered bicycles are very dangerous for riders