Easyjumper(TM) Multi-function Portable Car Jump Starter - Page 1
Forum section: electronics / general

author: max666
author_rank: Frequent Contributor
timestamp: January 31, 2015, 12:19:51 am
content: So I just watched Photonicinduction's commercial vidJust wanna hear what you guys think?

author: rx8pilot
author_rank: Super Contributor
timestamp: January 31, 2015, 02:50:06 am
content: I do not trust the presentation.I wonder how well things will work when 19v is connected to the car.I am guessing the box has a bunch of hobby grade Li-Po batteries that will catch on fire.

author: cs.dk
author_rank: Unknown
timestamp: January 31, 2015, 09:22:46 am
content: Seems too good to be true..The reviews/comments on Amazon are quite positive though.http://www.amazon.co.uk/product-reviews/B00Q77YQ9Q/ref=dp_db_cm_cr_see_all_top?ie=UTF8&showViewpoints=1&sortBy=bySubmissionDateDescending

author: mtdoc
author_rank: Super Contributor
timestamp: January 31, 2015, 09:34:59 am
content: Quote from: max666 on January 31, 2015, 12:19:51 amWhere's the teardown? I feel cheated.

author: German_EE
author_rank: Super Contributor
timestamp: January 31, 2015, 10:12:39 am
content: And no explosion (yet).The notebook output and the laptop outputs are separate so you won't be seeing 19V on your car accumulator connections. I do however have concerns about the power density in that thing, a short circuit will dissipate a lot of energy in a very small space.Li-Po, maybe, four in series will give you 14V, or perhaps it uses vacuum energy

author: Someone
author_rank: Super Contributor
timestamp: January 31, 2015, 10:22:30 am
content: Battery life, 3000 circles! Hilarious engrish.Also, not sure that a modern diesel uses glow plugs when starting except in extreme cold.

author: george graves
author_rank: Super Contributor
timestamp: January 31, 2015, 10:31:25 am
content: Quote from: rx8pilot on January 31, 2015, 02:50:06 amMost like the same. Most electronics in a car can handle 19 volts for a good long time. Voltage regulators on alternators often fail - and when they do, sometimes they go high for a while.

author: SeanB
author_rank: Super Contributor
timestamp: January 31, 2015, 10:47:27 am
content: Car electrics have to survive a 24V jump start for 30s without failing ( headlamps and other bulbs exempt as they typically are disabled by the ignition switch during starting) so this likely is just 4 Lipo cells in series without a charge controller on the battery jump output. Looks like there is a big diode on the positive lead though, in the cable, probably to prevent charging from the alternator.Funny thing is the SL engine uses a reduction starter, so the current drawn is not terribly high. If you want a real test use an older vehicle like a 1960's V8, which would have used a direct operating starter and a Bendix, not a pre engaged starter. Any V6 or V8 with a push button starter relay in the engine bay will severely test that unit, as those use a massive battery to supply the current needed.

author: max666
author_rank: Frequent Contributor
timestamp: January 31, 2015, 05:36:43 pm
content: What's the peak discharge current for lead acid batteries? 10C?So with Lithium-Ion-Cells capable of 45C and even 90C for a few seconds these days, I guess it would be technically possible to do this correctly. However somehow I doubt that this thing for £59.95 has cells capable for doing this. Plus if you connect it to a flat battery AND start the engine, the battery will suck it's fair share as well.I would have thought the thing in the positive lead cable is some over current protection maybe ... curious to see what would happen if you short the leads.During the last few seconds of the video I suspect Photon was tapping the leads a little, but the bastard doesn't really show it

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 31, 2015, 06:53:03 pm
content: http://www.candlepowerforums.com/vb/showthread.php?391602-what-LiFePO4-configuration-are-used-in-these-jump-start-power-banksTeardowns reveal that the batteries are basically R/C batteries, and most likely the cheapest kind. Therefore, you might as well just buy some from Hobbyking and get a lot more for your dollar.

author: rx8pilot
author_rank: Super Contributor
timestamp: January 31, 2015, 07:18:59 pm
content: Poorly managed Li-Po batteries are dangerous. Wondering if a respectable lab signed off on that CE label.When operated at MAX current, the Li-Po's don't have much of a life from what (little) I know. At the asking price, I am guessing the cheapest cells available are in there. Not what I want in my engine compartment where in-extinguishable fire is not welcome.

author: Zepnat
author_rank: Regular Contributor
timestamp: January 31, 2015, 09:02:40 pm
content: Quote from: rx8pilot on January 31, 2015, 02:50:06 amHe's right nothing dodgy going on, we have a very similar jump pack at the garage where I work and I've used it a few times.It's not designed to crank the car for any period just get enough power into the car to start it.The 19v is probably a boost converter ours measures 12v on those clips probably 3 cells in series.Ha probably so.Quote from: max666 on January 31, 2015, 05:36:43 pmIf the battery is totally flat I leave it connected for a minute to put some juice into the vehicle battery.The thing in the positive lead is a bunch of schotky diodes probably to prevent the alternator charging the jump pack batteries when the car starts. I know this because they melted off the PCB when we were cranking a non running ford transit, a new a lead was needed! The clips are pretty poor by my standards, being made of plastic but seem to last ok. I don't think there's any over current protection.I reckon max amps is around the 200 mark, ours will start any petrol engine and small (1.4-1.6) Diesel engines. It's been used it to start a couple of 2.0 diesels it cranked kinda slow but got them started easily enough.If there's a underlying issue where the car won't start then this jump pack is no good. But if someone's left their lights on or if the battery is just too weak to start the engine then these come into their own.So why bother might you say, what's wrong with a car battery and pair of jump leads?Well convenience. I've had to carry a battery and leads 100yards around the back to get a motor going and it soon gets a chore. Plus customers are amazed when you pull this out your pocket and it gets their car going!

author: max666
author_rank: Frequent Contributor
timestamp: February 01, 2015, 12:01:56 am
content: Quote from: NiHaoMike on January 31, 2015, 06:53:03 pmThanks for pointing out that thread! Interesting readSo yeah, apparently schottky diodes in the positive lead, no current protection, and cheap Li-Ion packs ... why am I not surprised.

author: amyk
author_rank: Super Contributor
timestamp: February 01, 2015, 02:31:29 am
content: It looks like they are at least balance-charging the cells, but one test in the linked thread reveals only 2400mAh capacity.Their ability to catch fire is certainly scary:http://www.flyinggiants.com/forums/showthread.php?t=51563(That fire was caused by unbalanced charging...)

author: rx8pilot
author_rank: Super Contributor
timestamp: February 01, 2015, 05:25:07 pm
content: Yep. I would never want that stored in the back of my car, just above the fuel tank.

author: Skimask
author_rank: Super Contributor
timestamp: February 01, 2015, 06:25:27 pm
content: Not buying it...literally and figuratively...A lot of batteries that go bad only have a single dead cell killing the whole battery. Doesn't take a lot of external juice to cover for that dead cell and get it going again...until the next time you turn it off.In addition, all other things being equal, it's not going to take a whole lot of juice to turn over an engine that's otherwise in good shape in decent weather.Not like this thing is even remotely going to fire up an engine that's 100,000 miles overdue for a tune-up, been sitting out all night, -20F outside, low grade gas, and so on. You know...when you need it most...

author: SteveyG
author_rank: Unknown
timestamp: February 01, 2015, 08:50:45 pm
content: Quote from: rx8pilot on January 31, 2015, 02:50:06 amThere's not 19V connected to the car. It's 3 lithium cells in series, so around 12V.Quote from: Someone on January 31, 2015, 10:22:30 amYes they do. My car is one touch start and the glowplug light illuminates briefly before it cranks the engine. Remember at this time of year in the UK it's around freezing point anyway.

author: Rick Law
author_rank: Super Contributor
timestamp: February 02, 2015, 06:13:11 am
content: This unit probably is designed to jump start an electric car. After you get the car started, you can recharge this unit by the car's engine...Carry one of this on board, the limited range of electric cars will be a thing of the past.

author: eas
author_rank: Frequent Contributor
timestamp: February 02, 2015, 09:05:24 am
content: I tore down a powerall rosso but still haven't gotten around to editing the vids.Yup, it is a 3s lipo pack. Yes, its balance charged, no, there doesn't appear to be any sort of current or voltage protection on the 12v output beyond what is provided by a bunch of parallel mosfets in a little case on the cable which are there for reverse polarity protection, and yes, it works.When I was researching them I came across a lot of auto mechanics who had one version or another of the LiIon powered ones (no, not AGM LED acid) that they'd use to jump multiple cars a day for diagnosis.One reason to use a product like these instead of a RC pack, its pretty much self contained. Downside is that you probably shouldn't leave them in your car until you need them because of self discharge and the toll of overheating them. If you live somewhere with cold winters and leave it in the car, you may find you need to warm it up under your clothes for a while before you can get enough juice to deal with a cold engine.

author: Zepnat
author_rank: Regular Contributor
timestamp: February 03, 2015, 10:01:23 pm
content: Quote from: Skimask on February 01, 2015, 06:25:27 pmHmm resisting the sarcastic temptation to say if that's how you treat your cars you shouldn't have one in the first place I feel the purpose of this is exactly as you say, to provide a quick shot of power 150-200amps isn't going to blow any doors off but will get a car with a poorly battery going again.

author: Skimask
author_rank: Super Contributor
timestamp: February 04, 2015, 04:00:22 am
content: Quote from: Rick Law on February 02, 2015, 06:13:11 amCarry two of these on board, the unlimited range of electric cars will be a thing of the future

author: eas
author_rank: Frequent Contributor
timestamp: February 04, 2015, 05:49:40 am
content: I wish I had something like this the couple of times we somehow managed to drain the 12V battery in our hybrid. Hundreds of pounds of charged NiMH batteries held hostage because the dinky 12V didn't have enough juice to power up the control system.

author: Kevman
author_rank: Regular Contributor
timestamp: February 04, 2015, 06:35:34 pm
content: Quote from: mtdoc on January 31, 2015, 09:34:59 amThe Amazon link that cs.dk posted actually has an interior shot if you're curious.A more reputable version of this is the Noco Genius Boost. Noco has an excellent reputation as a car charger manufacturer (though mine causes FM radio interference...) The boost charges via USB, which is funny to me.I doubt any of these would be able to start my dad's Power Stroke. Or most of our tractors, for that matter.Quote from: SeanB on January 31, 2015, 10:47:27 amReduction starters still have a Bendix. In fact, its more important for gear reduced starters to have them because the gear ratio is even higher. And people use a 24v jump starter on a 12v car? I've never heard of such a thing.

author: Psi
author_rank: Super Contributor
timestamp: February 04, 2015, 06:53:52 pm
content: I doubt it can handle jumping my car when its dead flat.Maxwell super capacitors are a dead short when flat.

author: SeanB
author_rank: Super Contributor
timestamp: February 04, 2015, 07:21:19 pm
content: Quote from: Kevman on February 04, 2015, 06:35:34 pmYou never met a tow truck driver? That is a common thing they do to jump start a car very quickly.

author: Skimask
author_rank: Super Contributor
timestamp: February 04, 2015, 10:52:46 pm
content: Quote from: SeanB on February 04, 2015, 07:21:19 pm^^^ +1 ^^^Although I just asked a friend of mine that has a tow truck business. Said he uses some off the wall 18v system rather than a 24v system. Says he still gets roughly the same kick, but less chance of it blowing up something on the 'jump-ee' car. I mean you really gotta wonder if those cheap won-hung-lo branded car stereos could handle a solid 24v anyways...

author: abbotsmike
author_rank: Contributor
timestamp: February 17, 2015, 01:00:05 am
content: Bit of a bump, my dad was asking me about one of these for work (he's a mechanic) specifically wanting one that can start large turbodiesels (3l V6 or more). Most of the commercial ones seem to struggle with that, and the one he was looking at getting cost £180!I'm planning to build one, the way they should have been built. I think for £100 or less I can source a high drain 4S Li-Po, a BIG diode to do the reverse charging protection, a box with a lipo bag inside to contain the lot, and a balance charger. I have enough plugs, sockets and cable lying around to connect the lot up. Then hopefully, one monster compact jump starter!

author: eas
author_rank: Frequent Contributor
timestamp: February 17, 2015, 08:47:29 am
content: Quote from: abbotsmike on February 17, 2015, 01:00:05 amYou've basically described the constructor of the commercial unit I acquired, with a bag instead of a case, and, of course, the larger capacity.I'm guessing that using a big diode for isn't going to add anything but expense and voltage drop compared to the paralleled power transistors the commercial packs use for reverse current protection.

author: max666
author_rank: Frequent Contributor
timestamp: February 18, 2015, 12:00:42 am
content: Quote from: eas on February 17, 2015, 08:47:29 amI was going to say that at this high currents a p-n junction might actually be superior to the resistive character of a FET, since the voltage drop of a p-n junction primarily increases only logarithmically, while the voltage drop of a FET increases linearly. However a quick components check had me find MOSFET's with only 6 mOhm drain-source-resistance, which at 100 A for example would give 0.6 V voltage drop, while a comparable Schottky-diode might have 0.77 V and a normal diode might have 1 V voltage drop.Pondering about it for a moment has me come to the conclusion that this must be because we only have bugger all reverse voltage requirement. FET's that can handle reverse voltage of 100 V and more have dramatically higher drain-source-resistance, while p-n junction diodes can easily handle 600 V and still only show 1 V forward voltage drop.For example the MOSFET's I found, that can handle 600 V reverse voltage, don't have a drain-source-resistance of less than 50 mOhm, which at 100 A gives us 5 V voltage drop.

author: Stonent
author_rank: Super Contributor
timestamp: February 19, 2015, 03:03:52 pm
content: Maybe IGBT in it?