hybridfree/eevblog-posts huggingface dataset:
Unknown voltage controller  - Page 1
Forum section: electronics / general

author: ShmoeMo
author_rank: Newbie
timestamp: August 09, 2019, 10:08:55 am
content: Hey guys, got a small favour to ask of anyone who reads this. I have a GPU that im trying to mod BUT the issue i have ran into is that the voltage controller for the memory has been renamed to this weird name (picture attached) i cannot find anything remotely close to a VC by searching that "name" im assuming its a renamed IR series chip as thats what most of the renamed ones are one GPU's. If anyone could point me to the original chip or even just tell me what the FB and EN pins are on it that would be great.

author: f4eru
author_rank: Super Contributor
timestamp: August 09, 2019, 01:44:06 pm
content: unfortunately, there's often a code instead of the chip number.And it looks like a noname/obscure brand chip.a few solutions :1) Use google-fu, and search the internet. There are several SMD codebooks/cookbooks database of codes.2) search on digikey parametric to try to match a few with same housing and characteristics ("PMIC - Voltage Regulators - DC DC Switching Controllers" - if power FET is integrated, "PMIC - Voltage Regulators - DC DC Switching Regulators" if not)3) if you cannot find anything, just try to reverse engineer the schmematic around it (it may be an "unknown" obscure chip)4) Extreme solution : decap one exampleIf you just want to change the Vfb divider to modify the voltage slightly, you can do that without real knowledge of the chip itself. Start with a very small mod, and be extremely careful, make flawless joints on VFB, or you'll fry your GPU instantly.
FET SOA for pulsed linear regulator..not just  "single pulse" SOA - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: August 06, 2019, 07:58:21 pm
content: Hi,We are doing a pulsed linear regulator. Using the STD1NK80Z FET. The SOA graph only shows for “single pulse”. How are we supposed to know if our pulse train as shown is OK?Also, why do they specify Tj as well as Tc…Surely junction temperature is the significant one….paling the case temperature into insignificance?STD1NK80Z datasheethttps://www.st.com/resource/en/datasheet/CD00058073.pdf

author: David Hess
author_rank: Super Contributor
timestamp: August 06, 2019, 09:26:55 pm
content: Quote from: treez on August 06, 2019, 07:58:21 pmBetter datasheets include a thermal resistance versus duty cycle graph. Check the old Motorola power transistor datasheets. Motorola probably has an application note about it.QuoteThey specify Tc because it is the closest thing to Tj that you can actually measure unless you want to use the body diode for temperature measurement which is how it is done for semiconductor characterization. In an application without any heat sinking, Tj and Tc are effectively the same.
Melbourne Electrikhana 14 Sept 2019 - Page 1
Forum section: electronics / general

author: digsys
author_rank: Unknown
timestamp: August 19, 2019, 08:40:58 am
content: For anyone interested in EVs, both name brands and private converted, many available for test drives, we are starting a week long Electikhana on Sep14 -https://aeva.asn.au/content/melbourne-electrikhana-14-sept-2019Our Aurora solar club will also be on display (as we have a compound there :-) ) - Any queries welcome
Lithium Polymer bare cell supplier in Canada - Page 1
Forum section: electronics / general

author: Gribo
author_rank: Frequent Contributor
timestamp: August 02, 2019, 09:51:34 pm
content: Does anyone know of a good supplier of bare cells? A design I am supporting uses Kokam cells, however they went out of the small cell market, and I am looking for similar cell, preferably the same chemistry.
MIG-welding machine regulator - Page 1
Forum section: electronics / general

author: M-E
author_rank: Newbie
timestamp: July 20, 2019, 08:39:03 pm
content: I have an old MIG-welding machine which has broken.It seems to me it's a short circuit in the rotary switch used to ajust the welding current.Then the transformer has overheated, the isolation has melted and it too has a short circuit in it.I'm thinking of build a powerful regulator and replace that advanced "system" in the weldeing machine with my regulator (and rewind the transformer).I'm not sure about how much power i need.I'm going to weld steel, about 5mm / 0.2 inch thickness max, about 1mm. / 0.04 inch min -how many Amperes does it take?-How many Volts should the output have?Most imortant:-How should i build the regulator?I allready have the big rectifier and resistor (0.24 milli-Ohms) parallel connected to a Ampere-meter (0-250A) so i know they can take that high current.-What can i build using theese things?I know i shuold buy a new welding machine, but thoose are expencive, to expencive to me.Any suggestion is welcome!

author: cs.dk
author_rank: Unknown
timestamp: July 21, 2019, 08:37:54 am
content: The rotary switch usual switches between different transformer-taps in that type of machine. The welding current is regulated by how much wire you feed in.The attached typeplate is from a little garage-welder, an Automig 223 (200A) machine. It'll do 5 mm plate, but you have to crank it good up, to get a hot weld. I believe U0 on the typeplate is the OCV?

author: tautech
author_rank: Super Contributor
timestamp: July 21, 2019, 09:24:27 am
content: Quote from: M-E on July 20, 2019, 08:39:03 pmWelcome to the forum.Make and model ?I have an old Danish 180A Migatronic and I'd advise not to have anything smaller.

author: M-E
author_rank: Newbie
timestamp: July 21, 2019, 07:44:39 pm
content: "The rotary switch usual switches between different transformer-taps in that type of machine. The welding current is regulated by how much wire you feed in."-I know!It is a Cloos GLC 206.

author: tautech
author_rank: Super Contributor
timestamp: July 21, 2019, 08:23:16 pm
content: Modification is possible to electronic power control with a powerful enough Triac on the primary.Only use a special 4 quadrant Triac called an Alternistor.A quite simple control circuit using U2008B or similar will do the control.https://www.bucek.name/pdf/u2008b.pdfA good transformer rewinding reference:https://ludens.cl/Electron/trafos/trafos.html
FAA 100 W Lithium battery limit - Page 1
Forum section: electronics / general

author: Meshka7
author_rank: Contributor
timestamp: July 09, 2019, 08:22:54 am
content: Does anyone know where this limit comes from? Basically you can't carry more than 100 W Lithium batteries (including chargers). Unless you get permission from the airline and you are then limited to a maximum of 2 and not in checked bags. I can't find the source of this limit and what's the FAA trying to accomplish? Is 100W for example not very explosive? Are they trying to prevent malicious tampering with the Airplane electronics? Any idea?

author: nctnico
author_rank: Super Contributor
timestamp: July 09, 2019, 08:41:35 am
content: Lithium batteries may iginite spontaneously. If this happens in a suitcase in the cargo hold then the plane could get on fire. It is easier to contain in the passengers cabin because it is easier to notice. The power limit is to limit the amount of energy that can be released in an event so the fire can be put out by the cabin crew by pouring water over the battery pack or submerging the battery pack in water.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: July 09, 2019, 08:53:30 am
content: A 100 Wh battery is quite big one (for example. DJI Phantom 4 battery is 90 Wh and weights in at 470 g). Average traveler doesn't carry batteries much bigger than that (laptop batteries being in the ballpark) so the regulation is not much of a hindrance. Do you have some portable device that uses bigger batteries than that? I'm not sure I've seen any.

author: Rerouter
author_rank: Super Contributor
timestamp: July 09, 2019, 09:02:39 am
content: The limit is for over 100Wh per battery, you can have a large number of those sub 100Wh batteries provided they are packed suitably (generally in a flame proof bag or enclosure)e.g. you fly a quadcopter? well you can have a backpack full of 95Wh batteries, provided each is packed suitably, you will probably have it inspected, but it should get through no issue.I face the same thing with cordless drill batteries, can carry as many as I like, so long as each battery is under the limit. (and the terminal area is taped over)https://www.faa.gov/hazmat/packsafe/more_info/?hazmat=7

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 04:46:38 pm
content: Yes that's a "per unit" limit.But the number of units is not stated, up to the discretion of the officer.I doubt if a half-dozen would be refused.I doubt two dozen would be allowed.Putting them all in a special container may well reduce the number, IMO better to have a few here a few there but not making it obvious you're trying to be deceptive.Check out Grin's modular LiGo battery
Wallaby Rechargeables - Page 1
Forum section: electronics / general

author: Positive_Coefficient
author_rank: Newbie
timestamp: July 02, 2019, 10:00:10 am
content: Hi, has anyone done a test on these new Wallaby branded rechargeable AA and AAA cells which are about $2 each off ebay?I just received a pack of 4 AA cells and they feel pretty solid. Rated 2000mAh.

author: Audioguru
author_rank: Super Contributor
timestamp: July 02, 2019, 08:55:54 pm
content: The photo does not say the chemistry of the batteries. I assume they are older Ni-MH but they might be antique Ni-CADs.New local manufaturers make Ni-MH batteries (for the last 5 years) that use the Sanyo/Panasonic Eneloop chemistry that holds a charge for one year and they are sold pre-charged.

author: Positive_Coefficient
author_rank: Newbie
timestamp: July 03, 2019, 10:58:26 am
content: Indeed, Ni-MH and they are pre-charged with the claim that they retain 80% charge after 12 months.
Potential game changer: Kyocera to roll out new Li-ion battery in 2020 - Page 1
Forum section: electronics / general

author: Mr.B
author_rank: Unknown
timestamp: July 10, 2019, 08:03:36 pm
content: https://japantoday.com/category/tech/kyocera-to-roll-out-new-li-ion-battery-in-2020TL;DRCompared to current Li-ion battery technology:Safer and more reliableReduced material cost by about 40%Maybe as much energy density as 500Wh/kgSignificantly more easily recycled

author: Kjelt
author_rank: Super Contributor
timestamp: July 10, 2019, 08:52:23 pm
content: Its not even a factor two in energy density.In the 90s we had a saying that a customer would be very interested if a new product had a gain of 6dB, but 12dB would be a game changer, anything less is slow progress.

author: thm_w
author_rank: Super Contributor
timestamp: July 10, 2019, 10:32:18 pm
content: Quote from: Kjelt on July 10, 2019, 08:52:23 pmok, not all industries are the same.Technologies such as Nimh and Nicd have completely leveled off for example.

author: tytower
author_rank: Contributor
timestamp: August 03, 2019, 04:04:18 am
content: I was looking for LiFePo4 results but don't see any ? I'm surprised .Anyone able to point me to a similar graph for LFP please ?
PFC inductance - Page 1
Forum section: electronics / general

author: semir-t
author_rank: Regular Contributor
timestamp: June 17, 2019, 07:28:40 am
content: Hi,I am workign on universal power supply which I found onTI web site. It is universal 400W switching power supply. I am trying to fully understand it first, all the parts like EMI filter, PFC correction circuit, Buck circuit etc, and likely I will have more questions further down the road.The main idea is to redesign this circuit so that it can power 500W load.I started with PFC and I got little stuck with inductor selection. I spent lot of time learing about the PFC and topologies (CRM and CCM), single channel and double channel interleaved. So I understand that part.On the attached image is the PFC circuit. So we have 2 channel interleaved configuration that is based around UCC28063DR. Based on the datasheet, for my case (500W output) I managed to calculate inductance L1=L2=121 uH, IL_PEAK= 9.7365 A and IL_RMS= 3.97 A. NP/NS = 8.On the original schematic, they are using PFC4124 shown in the attachemnt section. I know that the current for the interleaved mode is lower thous we can use smaller inductance so I assume this is why output power for this inductance is 300 W. But can I reause this inductance in my case when I want to have 500W output and considering values I calculated.Thanks,

author: fourtytwo42
author_rank: Super Contributor
timestamp: June 18, 2019, 01:17:55 pm
content: So are you asking if you can design a pfc controller using manufacturer A's part with data from manufacture B ?
220W Microinverter with 350W PV panel - Page 1
Forum section: electronics / general

author: jaranguren
author_rank: Newbie
timestamp: June 12, 2019, 08:43:28 pm
content: HiCan a 220W rated Microinverter be safely used for harvesting energy from a 350W PV panel?Thanks!

author: The Soulman
author_rank: Super Contributor
timestamp: June 12, 2019, 08:57:52 pm
content: If the open circuit voltage of the panel (Voc) doesn't exceed the maximum input voltage of the inverter, it *should* be safe.

author: Seekonk
author_rank: Super Contributor
timestamp: June 14, 2019, 09:50:38 pm
content: This is commonly done as most of the day the panel produces way less power. The inverter will self limit. Though, commonly that power inverter will be used with a 250-280W panel. It is just more economical. Such a big difference sounds like an installer trying to under bid on a system that sounds more powerful than it is.

author: gbynum
author_rank: Newbie
timestamp: June 15, 2019, 11:49:43 pm
content: (Array directions assume northern hemisphere; we have southern hemisphere folks here too, I know)If the panels do not point south, this "overpanelling" is not unusual. There is one user on the solar website with arrays to the east, south, and west which give better production over longer periods of the day.I probably would not recommend a southern array with panels that much over the inverter ratings unless the inverter manufacturer says it is ok.
Highest practical power level for offline led driver (240vac) - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: June 11, 2019, 05:21:03 am
content: 200W Offline LED driver, 240VAC input. Done with Power factor corrected Boost then LLC.Output 250V, 0.8AEfficiency would be 93%....but do you agree, that a 1kW LED Driver is not really practical, because the current would have to be so high and the LEDs would need to be paralleled, which is sub-optimal. As such, 200W is the highest comfortable level for LED drivers off 240VAC? Higher powers should be dealt with by just having multiple 200W drivers?I am talking about having the driver mounted at floor level, and the leds mounted in the ceiling.You can buy very high current leds, but they are rare, and they have supply iussues...as such, we really need to keep to more common current level COBs and LEDs....hence the lower power..you agree?

author: dmills
author_rank: Super Contributor
timestamp: June 11, 2019, 11:40:55 am
content: Not really, I could see a kW (or even a 3kW design) where the Input stage and PFC boost converter are common parts and the thing has say 6 outputs for the LED strings.Hell for some applications a series string totalling bignum volts is quite practical, they do this with runway lighting (28V lamps in series with the lamps designed to go short circuit when they fail (In the manner of old school christmas lights), fed from a current source at maybe a 1,000V compliance.There was even street lighting that was done as a series string (with similar shorting contacts when the filaments failed) that again was a few kV supply to the string, mainly a US perversion I believe.There are odd use cases for almost anything you can imagine, they may be too niche for your company but that does not mean that they don't exist.
isolated DC converter input filtering - Page 1
Forum section: electronics / general

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: June 09, 2019, 06:55:54 am
content: There is a 47uF electrolytic on the same net as power input near the DC converter. But I didn't include the recommenced LC input filter. I did LC filter the output which wasn't needed for this isolator. Consumed output power on isolated side will be ~0.375W.Is the lack of an input LC filter going to cause lots of noise?

author: E.Buer
author_rank: Contributor
timestamp: June 09, 2019, 08:52:07 am
content: The lacking LC filter will increase the noise on the input rail. This could lead to increased EMI.Not sure if it would affect the output of the regulator.

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: June 09, 2019, 09:38:53 am
content: Quote from: E.Buer on June 09, 2019, 08:52:07 amBoard was canceled and ordered board with LC filter on both sides of isolated buck module.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 09, 2019, 04:37:05 pm
content: Diff filtering usually isn't as important as CM is.Forget if I've used that module before, it might not be too bad. It probably won't pass FCC Part 15 if that's important.Tim
estimate the running time for 3 led in parallel - Page 1
Forum section: electronics / general

author: khiworld
author_rank: Newbie
timestamp: June 19, 2019, 09:25:00 am
content: Hello.This is what I did....I got one 3.7v/ 1000mAh Li ion batteryV_battery flows to LED driver.......I set the resistor value for my target led current. V_fb is fixed to be 0.1V3 LED in parallel.Case 1.R is set to be 0.43. so, I_led = V_fb / R = 0.1v / 0.43 = 235mACase 2.R is set to be 0.51. I_ led = 0.1v/ 0.51 = 196mASimple calculation MeasurementCase 1.1000mAh / (3*235mA) = 1.42 hour = 85min 150 minCase 2.1000mAh / (3*196mA) = 1.7 hour = 102min 174 minPlease correct me if I did wrong.Thanks
India boasts world's first totally solar powered airport... - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: January 31, 2019, 06:56:23 am
content: World's first totally solar powered airport...https://www.voanews.com/a/southern-india-boasts-worlds-first-fully-solar-powered-airport/4760637.html

author: boffin
author_rank: Unknown
timestamp: February 26, 2019, 08:54:17 pm
content: Quote from: cdev on January 31, 2019, 06:56:23 amWell, yes and no. They pump excess power into the grid, and use grid power at night.As for 1st, other airports in the Caribbean (Antigua's, St Kitts) already do exactly the same thing.https://www.caribjournal.com/2016/02/23/the-caribbeans-biggest-new-solar-energy-project-is-at-antiguas-airport/https://www.caribjournal.com/2013/09/17/st-kitts-and-nevis-completes-construction-of-airport-solar-farm/But hats off to any organization that does this, it's a good idea, and airports tend to have some excess [nice and flat] land around them.

author: boffin
author_rank: Unknown
timestamp: March 07, 2019, 05:39:32 pm
content: Quote from: george80 on February 26, 2019, 10:46:22 pmWho peed on your cornflakes this morning?If the airport generates more electricity (overall) using solar than it consumes, 99.999% of the world is happy to say "it's powered by solar".The fact that it has to feed excess back to the grid during the day and grab a little at night is just a great side affect, because electricity grids need extra day-time generation generally, and demand at night is lower.

author: apis
author_rank: Super Contributor
timestamp: March 10, 2019, 07:06:29 pm
content: Quote from: george80 on February 26, 2019, 10:46:22 pmAviation is responsible for 12% of CO2 emissions from all transports sources, so the industry does what it can to try and improve their public image a little. Still, more solar is a good thing in itself.

author: Achu
author_rank: Contributor
timestamp: June 08, 2019, 02:54:40 pm
content: I live there and I've been to the Cochin International Airport(CIAL).It fully runs isolated from the grid.Though I do not know if it is the first one.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: June 08, 2019, 07:02:02 pm
content: It surely is interesting, but of all energy moved/spent on an airport most goes into the fuel for the planes. The rest is probably a few percent for lighting and maybe air condition, climate control, antenna systems.It would be like outsourcing the fueling to a different company and saying : see, our company does not emit carbon.But i agree, the airports usually need a flat area, without forest and that area can be used for solar panels. Might even help them with avoiding bird strike for offering less nesting area.
DC power relays for 250Vdc - Page 1
Forum section: electronics / general

author: Gribo
author_rank: Frequent Contributor
timestamp: June 08, 2019, 02:33:22 pm
content: Hello all,I am looking for SPDT or DPDT power relays for 250Vdc/10A loads. Does anyone know if such part exists? Omron has the G9EB, but those are SPST.I am testing a high voltage, high current DC power supply, and would like to move away from MCBs.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: June 09, 2019, 02:44:20 am
content: KILOVAC EV200 Series Contactor With 1 Form XContacts Rated 500+ Amps, 12-900VDC

author: floobydust
author_rank: Super Contributor
timestamp: June 09, 2019, 03:39:02 am
content: Look at solar energy relays, like FujitsuFTR-J2.200V per contact, two contacts in series gives 450VDC 10A.

author: Gribo
author_rank: Frequent Contributor
timestamp: June 09, 2019, 02:51:31 pm
content: Thank you both, I will order few units of the KiloVAC.
Brief Q about hand-powered flashlights/torches - Page 1
Forum section: electronics / general

author: Vell
author_rank: Contributor
timestamp: May 30, 2019, 09:38:27 pm
content: Yrs trly is fond of flashlights, and in past years bought a number of hand-generator types; iirc some with rechargeable batteries. Many had little dynamos (generators with DC output}. However, after only tens of hours or so of use/charging, the brushes and maybe commutators failed. Question is, why so quickly?The little dynamos looked just like small low-voltage motors, such as those made by Mabuchi. I didn't open up any, iirc; they might have been designed as motors, but used as generators.Alternators with rectifiers worked well for some time.(I still have a couple of Duracell "silver eggs"; it's all too easy to damage their rechargeable coin cells so they self-discharge quickly. When charging, follow directions ad limit cranking to 120 rpm, almost sure. Torque load decreases as the cell charges, so once the crank turns quite freely, you're charged.)
Charging a big capacitor - Page 1
Forum section: electronics / general

author: lilmantis
author_rank: Contributor
timestamp: May 30, 2019, 04:28:06 pm
content: Hello, what is generally the best idea for a CC capacitor charger implementation?my Case: 12-24V input and 35V output on the capacitor. Capacitor is half drained periodically to power some LEDs so it will vary between 17-35V.I tried SEPIC and ZETA topologies but I get very high currents.I am thinking about a constant current converter but this is complex and expensive. Any suggestions?
Futre of Tesla and EVs and EV apps  - Page 1
Forum section: electronics / general

author: DougSpindler
author_rank: Super Contributor
timestamp: May 01, 2019, 06:31:59 pm
content: In the post about the Future of EV's I leaned a lot about EVs. Sadly someone closed the post.Since this is an experiment in progress I would like to continue the discussion.Starting it off with an talk just given about Tesla.https://climateone.org/audio/insane-mode-tesla%E2%80%99s-wild-rideI own a PHEV and recently drove from San Francisco to Ojai, California near Santa Barbara.I own a Volt which is a PHEV. Price for regular gas in California rally high, we are paying $4.25 / gallon. Last month I was paying $3.25. I didn't think I could find a charging station in the tiny town of Ojai, but to my surprise I found several thanks to the ChargePoint app. Spent the day in Ojai and was able to chare my car for around $6.75. - Fantastic!PHEVs are wonderful - What I don't understand is why GM is discontinuing the Volt. Far better than a BEV, and certainly much better than an ICE. I can't imagine ever buying an ICE car ever again.

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 02, 2019, 07:04:29 am
content: IMOP it got closed because it became a thread full of mindless video's with no meaningful content, nothing but claims & counterclaims!

author: DougSpindler
author_rank: Super Contributor
timestamp: May 02, 2019, 09:21:29 am
content: Quote from: fourtytwo42 on May 02, 2019, 07:04:29 amYes and no. I learned a lot from that thread. Learned many things about Tesla, EV batteries and charging stations. At the same time I learned why biofuels, hydrogen cars, HHO generation and solar roadways are all bullshit. By no means am I an expert, but thanks to that thread I can now explain how stupid all of those technologies are.As Tesla and EV cars are an experiment in progress, it would be nice to continue the conversation. I see Tesla is had just introduced the Model S in the UK this week. Really have to give Elon Musk for disrupting the car industry. I don't think so many car companies would have EV cars if it were not for Elon.
18650 Cell voltage monitoring - Page 1
Forum section: electronics / general

author: Nitin25
author_rank: Newbie
timestamp: May 01, 2019, 05:27:08 am
content: Does anyone worked on battery monitoring system ?While monitoring 18650 cells How to sense individual cell voltage with the help of microcontroller. As microcontroller accept up to 5 volt.So if I connect few number of cells in series voltage crosses the 5 volt limit. Voltage divider circuit is fine at certain series cells. But it has very very bad efficiency.So anyone have idea how to measure individual cell voltage ??

author: beanflying
author_rank: Super Contributor
timestamp: May 01, 2019, 05:46:23 am
content: Firstly Welcome.Secondly DO NOT CROSS POST and start multiple topics about one project.QuoteThirdly NO I will not design you a system in private because you sent me a PM.Fourthly I and others may help you with your project if you give some details of it. So how many 18650 cells what BDLC motor and controller ...... We can not read minds.

author: digsys
author_rank: Unknown
timestamp: May 01, 2019, 06:03:19 am
content: Quote from: Nitin25This is a BMS I designed and use on EVs, mostly solar cars. A few teams have used it as well. All circuits and layouts are provided free to use.The main IC is a differential op-amp, capable of monitoring voltages of up to +/- 250VDC difference. That's app 50+ series Li cells.https://pbase.com/digsys/image/161061565More pix athttps://pbase.com/digsys/projectsHook it up to any LV MPU etc

author: Yainakorn
author_rank: Newbie
timestamp: May 02, 2019, 07:14:06 am
content: I think there is a confused answer to this post.
Diode to charge series batteries in parallel? - Page 1
Forum section: electronics / general

author: Webserfer
author_rank: Newbie
timestamp: June 03, 2019, 03:40:04 pm
content: Title says most. I have 3 12v lead acid cells that are hooked up in series on an old server UPS. I also have an old 18w? solar panel.Would hooking that up to a cheap standard ebay voltage regulator work as a solar regulator? And if I used diodes to prevent shorting out the batteries could I run/charge all of the batteries off the one regulator?I cant see why the diode wouldn't work for parallel charging but I'm not good at this and don't wanna miss anything.The voltage regulator as a solar controller is one that's got me in if it'll work or not though.Appreciate the help!

author: f4eru
author_rank: Super Contributor
timestamp: June 03, 2019, 04:09:36 pm
content: QuotePlease provide a schematic, so we understand your configuration better, You can use a scanned DaveCAD, or online schematic tools.also, please provide a link to this "cheap standard ebay voltage regulator", because there are many "standards",https://xkcd.com/927/

author: Webserfer
author_rank: Newbie
timestamp: June 03, 2019, 05:00:47 pm
content: Ah sorry, my bad. I meant one of these buck? regulatorsSlightly embarrassing, I don't know how to do cad yet. Don't know the icons ect. Here's the best I could get with paint, horrendous I know.If their were no diodes the connection to the regulator would just short out the batteries, would the diodes there prevent that or is their something I'm missing?Thanks!

author: f4eru
author_rank: Super Contributor
timestamp: June 03, 2019, 11:55:13 pm
content: That cannot work:1) you short plus and minus of the regulator through the series connection of the batteries. it's either series or paralell, not both.2) those regulators typically don't have a nice current limitation, the implemented curent limit is intended as a protection, not a charger circuit. They may self distruct over time if used as a charger.For schematics, try out :http://www.schematics.com

author: daveatol
author_rank: Regular Contributor
timestamp: June 04, 2019, 12:48:07 am
content: You can just charge them in series. You'll need a boost converter if the panel voltage is not high enough. You'll also want the converter to regulate the panel voltage somewhat so that it doesn't pull it low and reduce the output power.
Hybrid System-Help Appreciated - Page 1
Forum section: electronics / general

author: OpenCircuit
author_rank: Regular Contributor
timestamp: December 14, 2018, 03:09:30 am
content: Based on my photo it looks like I will have a current "feedback" problem from either source into the other non-producing source. Can I simply solve this with large enough diodes? Each source (turbine and panels) have separate CCs.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 14, 2018, 04:04:00 am
content: The charge controllers should already include diodes.

author: Kensmash
author_rank: Newbie
timestamp: April 01, 2019, 08:03:33 am
content: I feel that you will definitely know this.
Interesting book - David MacKay : sustainable energy, without hot air - Page 1
Forum section: electronics / general

author: paulca
author_rank: Super Contributor
timestamp: April 09, 2019, 12:21:50 pm
content: http://www.withouthotair.com/I like the part 1 tag line. "Numbers, not adjectives"

author: tggzzz
author_rank: Super Contributor
timestamp: April 09, 2019, 12:42:45 pm
content: It is an excellent book, very useful for doing all sorts of back-of-the-envelope calculations.I particularly like his half-dozen scenarios for the UK's future energy supply, where he is both interested and disinterested in the choice. All he cares about is that the arithmetic adds up.Another useful soundbite: "there are huge problems" plus "there are huge opportunities" - but which huge is huger.It is available as HTML and as a PDF.Shame MacKay died.
Sources of broken PV cells to solder together + good alt.energy book to buy? - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: December 01, 2018, 02:18:02 pm
content: Hi.I am looking for two things, a good alt.energy /PV book and a source of solar cell material 'seconds' to play with.In the past, people could buy bags of pieces of solar cells and solder them together to make DIY solar arrays of any size they wanted. Can I still do this, and if so, where can I get a good price on good quality base material. I am not averse to soldering to get cheap panels. This is what they do in the Third World.Initially, I'd like to make some solar cells to wire some sensors to, so they would not be so dependent on my constantly replacing or recharging their batteries.Also, what would I need to do to use the produced power more consistently? (Joule thief circuitry? micro scale DC-DC conversion?)Actually, I would love to buy a physical book on this subject. (that would be more useful than a digital book in extended power outages!)Is there a "Bible" of alternative energy information these days, kind of like the old "Whole Earth Catalog", which if I remember correctly, contained lots of info on stuff like PV?A big, perennially useful paper book.

author: fourtytwo42
author_rank: Super Contributor
timestamp: December 02, 2018, 07:23:41 pm
content: Sure you can do that (solder together) I have seen such things advertised on Ebay (shattered bits) but then if your going to use it outdoors you have to encapsulate it etc and frankly the price of finished panels per W is now low enough it's hard to compete with DIY.As for books you don't say what country your from but the local library is usually a good source for starters.
More solar snake oil - Page 1
Forum section: electronics / general

author: Seekonk
author_rank: Super Contributor
timestamp: July 31, 2018, 02:12:25 pm
content: Is this the batterizer of solar?www.photonomi.comPromises of enormous gains, not little.

author: Ian.M
author_rank: Super Contributor
timestamp: July 31, 2018, 04:31:14 pm
content: Well, its certainly got an odour of ophidian short-chain lipids about it.Typical clear sky daylight is an order of magnitude less irradiance than direct sunlight. Overcast sky daylight is usually at least another order of magnitude down on that. Therefore at best, the energy density for worthwhile output without direct sunlight just isn't there unless the panels have a total installed cost per unit area of less than a tenth of that of conventional photovoltaic or solar thermal panels. To be a game-changer they'd need to be a hundred times cheaper.

author: f4eru
author_rank: Super Contributor
timestamp: August 03, 2018, 11:18:09 am
content: Not exactly.The blue sky excluding the sun is low irradiance, in the order of 5% of full sunlight.Overcast sky is typically much more, 7-20% of direct sunlight.https://www.nasa.gov/images/content/57911main_Earth_Energy_Budget.jpg

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 03, 2018, 07:40:05 pm
content: They had me at nanotechnology.Without really explaining any technicals it does sound like some BS to me that will never see the light of day. One of those things that's only there to wow investors.People keep trying to reinvent solar. I think all that effort should go towards more efficient PV modules and simpler/cheaper manufacturing processes. That is already happening to some degree.

author: Wan Huang Luo
author_rank: Regular Contributor
timestamp: November 07, 2018, 02:30:42 pm
content: Quote from: Red Squirrel on August 03, 2018, 07:40:05 pmThere's no doubt that the word "nanotechnology" has been abused to the point of de-legitimizing real nanoscience.
Are there transportable Lion battey-packs for a home solar system? - Page 1
Forum section: electronics / general

author: max5star
author_rank: Newbie
timestamp: November 05, 2018, 09:47:01 pm
content: I'm working on this project about renewable energy and I'm tying to figure out if its possible to have a battery pack that can be easily disconnected, moved, and reconnected from one solar panel system to another, if given the right base mounts. or are they too complex to easily remove. I'm prety new to this. Anyone have an idea?

author: electrodacus
author_rank: Super Contributor
timestamp: November 06, 2018, 04:27:56 pm
content: Quote from: max5star on November 05, 2018, 09:47:01 pmA battery that will have any sort of usable capacity will be to heavy to move easy and not sure how that will be useful. There are already plenty of small portable battery power packs if this is what you are referring to.At a minimum you will need the battery and a BMS + charger to connect to a PV panel or PV array and this assumes you only want to use DC else you will also need an inverter already to much for comfortably moving this from one place to another. Not sure what you want to do exactly.You can check myopen source Solar BMSdesign that is now on Kickstarter

author: nctnico
author_rank: Super Contributor
timestamp: November 06, 2018, 06:41:41 pm
content: I'd look at packs intended for electric motor cycles. Some are designed to be taken out of the motor cycle to charge inside.

author: free_electron
author_rank: Super Contributor
timestamp: November 07, 2018, 02:16:14 pm
content: yup. we have trailer mounted packs that can power entire streets. Deployed in disaster area's like Puerto Rico and Florida( hurricane )This one was installed in slightly over a week :https://electrek.co/2017/10/24/tesla-unveils-first-solar-storage-projects-hospital-puerto-rico/or were you looking for something smaller ? weight is the problem. These thing are heavy.

author: tautech
author_rank: Super Contributor
timestamp: November 08, 2018, 02:36:36 am
content: Quote from: max5star on November 05, 2018, 09:47:01 pmPick your needs from this range and look at the weight spec:http://en.thundersky-winston.com/product/tqkqsgbdcfy.html

author: mtdoc
author_rank: Super Contributor
timestamp: November 13, 2018, 04:58:35 am
content: Sure. Depending on the size and configuration of the battery bank, it is very possible to move, even heavy lead acid battery banks. Of course for a typical large system, it may mean moving several 20 kg or larger batteries or not - it really just depends on the type of battery bank and the size of it components.There is no real complexity involved in the battery bank connections. Just the large cables connecting positive and negative terminals to the rest of the system and also usually a temperature sensor wire.. there will also typically be interconnects between individual battery bank batteries or cells.
4x 22Voc panels into a 100v max controller, cutting it too close? - Page 1
Forum section: electronics / general

author: Red Squirrel
author_rank: Super Contributor
timestamp: October 13, 2018, 01:31:46 pm
content: Thinking of changing my plans for a small solar setup, I have 4x 100v panels with a VoC of 22v that will be going into a charge controller that can take up to 100v. Was going to group them in two, so 2x 44voc in parallel, but I'm thinking I can probably get away just putting them all in series to simplify things. That brings me to 88 Voc.Would this be cutting it too close, or should I be fine? Under normal conditions it's not actually going to see the open circuit voltage anyway as it will be brought down from load but want to look at worse case scenario. 22 Voc is also calculated at 25C. How much of a difference can I expect at -50C? We don't get those temps much anymore these days, but it's still something to consider.

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 13, 2018, 02:15:22 pm
content: The problem is you dont know the quality of the components used in the charge controller nor the headroom allowed for, if for example it uses cheap 100V electrolytics on the input the lifetime would be short. As for the tempco my panels are specified at -0.3% per degC so potentially you could reach 102.6V@-50C if your really get those temperatures!Perhaps you could find a charge controller with a higher input voltage rating ?

author: Red Squirrel
author_rank: Super Contributor
timestamp: October 13, 2018, 03:58:02 pm
content: Already bought the controller and been using it so don't really want to buy another. It's an Epever. Not sure if that is a well known brand or not. It "feels" of good quality though, if that means anything.Guess to play things safe I should stick to my original plan. I figure chances are I'd be fine since there will always be some kind of load that brings the voltage down, but if for any reason something was to get disconnected, and then reconnected that's where the danger could be.

author: Red Squirrel
author_rank: Super Contributor
timestamp: November 07, 2018, 06:47:11 pm
content: So had this running for a bit now. 2 groups of 2 panels in parallel then those two groups are in series. I typically get 44 volts into the controller unless the battery is low then it might dial down depending on MPPT curve etc. Like so far I have yet to see sun light so it's usually working under overcast conditions only so the charge controller is just sipping any available current from the panels. Don't have much in terms of load other than the inverter and any time I turn lights on. Can't wait to see it under actual sun light. Maybe in January. When it gets really cold ironicly the sun is out more.Still need to add some monitoring and automation (low voltage shut off, outside lights on timer etc) but that will be another project. Probably go arduino based.
Custom solar panel - Page 1
Forum section: electronics / general

author: congruentsquare
author_rank: Contributor
timestamp: October 25, 2018, 01:18:59 am
content: I would like to build a custom solar panel to maximize the charge surface on the top of my van. Looking through youtube it doesn't seem hard to do but I can't seem to find any guides out there on how to do this properly. Has anyone built a custom solar panel? Is it a good idea?

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: October 29, 2018, 12:26:09 am
content: Greatscott did a good video on it. At the end of the day I would recommend just buying commercial panels as these are well engineered to withstand the environment, and anything you try to DIY will probably not come close in terms of reliability

author: Red Squirrel
author_rank: Super Contributor
timestamp: October 29, 2018, 05:31:20 am
content: I looked into this too just because it's so hard to find premade ones without getting raped on shipping. But I ended up finding some 100w ones on Amazon for $160 with free shipping so went with those. Also found another site after the fact that sells bigger ones and does not charge that much for shipping. So they're out there, just hard to find as when I was searching most of the sites I found always ended up being in the US even if I put Canada in my search query.While looking into making my own I did come to the conclusion that it would actually end up being almost the same price, maybe even more expensive. So the only real reason to make your own is if you absolutely can't find/get premade ones. Otherwise I'd go with ones you can buy.

author: Seekonk
author_rank: Super Contributor
timestamp: October 29, 2018, 01:28:57 pm
content: There is a horrible history of home made panels going bad in a couple of years. Go with grid tie panels. I can buy these new from local installers, nearly 300W for $130 and no shipping. They always have loosies they want to get rid of. They buy whatever brand is cheapest that week and they often don't match ones from the last batch.

author: Red Squirrel
author_rank: Super Contributor
timestamp: October 30, 2018, 12:19:41 am
content: I guess if you are lucky enough to have local installers then yeah it's a no brainer. That price is crazy cheap. You can't even buy the cells alone for that cheap.

author: congruentsquare
author_rank: Contributor
timestamp: November 03, 2018, 03:34:33 pm
content: The reason I want to build a solar panel is to maximize the surface area using a custom panel shape/config.After a bit of research I've found that it would be hard to do reliably.Specifically I need to use flexible solar cells that will be mounted on a metal surface and be subjected to scraps and bangs.
Solar and battery - Page 1
Forum section: electronics / general

author: radhika
author_rank: Regular Contributor
timestamp: September 26, 2018, 12:40:58 pm
content: I have 4000mah 3.7V battery and 4000mah means that it draws 4A for the whole time in one hour (https://www.ifihomes.com/blog/how-much-time-it-takes-to-charge-a-solar-power-bank/).Is this means that it's output current is 4A? What is the meaning of draw here? Is this mean that 4A is the maximum current it holds?How much voltage and wattage of solar cell need to charge this battery?

author: ahbushnell
author_rank: Frequent Contributor
timestamp: September 28, 2018, 10:59:47 am
content: Quote from: radhika on September 26, 2018, 12:40:58 pmThe 4000 mA-hr rating means it can deliver 4 amps for one hour or .4 amps for 10 hours. Note thare will be a maximum current limit on the battery.You need a charger to control charge to the battery. This will avoid damage to the battery and potential fire.The energy in the battery is roughly the amp-hr rating times the voltage. The voltage changes during discharge and goes down. So you need to integrate to get an accurate energy store value.The rough numbers would be 4 amp-hr * 3.7 volts= 14.8 watt-hr.The power depends on the current. So if you are discharging for 10 hours with a current of .4 amps the power is 0.4 amps * 3.7 volts=1.48 watts.watt-hr or kW-hr is energy.watt or kW is power.
Charging voltage for 16 volt Lithium iron phosphate battery? - Page 1
Forum section: electronics / general

author: Circlotron
author_rank: Super Contributor
timestamp: August 13, 2018, 01:14:32 pm
content: A friend recently bought a lithium iron phosphate battery for his race car because it is about 40 pounds lighter than the lead acid battery he was using previously. It has gone flat a couple of times because it wasn't charged properly, and we are trying to figure out the correct maximum charging voltage to limit it to. Trouble is, even though the label says it is a 16 volt battery it also says not to charge any higher than 15 volts... I'm thinking the label is for the 12 volt version with permanent printing saying no higher than 15 volts and the added laser printing saying it is the 16 volt version. Anyhow, what should the maximum charging voltage be, and could someone direct me to a site telling info about charging these things?Edit-> found it should be 3.65 volts per cell. During discharge is 3.2 volts per cell and 3.2 x 5 cells = 16 volts, so 3.65 volts x 5 = 18.25 volts charging.

author: theoldwizard1
author_rank: Regular Contributor
timestamp: September 25, 2018, 02:45:38 pm
content: Ahh .. the old race car using a high voltage battery ! This typically will only works on race cars used in short races that have no alternator and old fashioned point ignition system.At one time, they actually sold 7 cell lead acid batteries just for this purpose ! Some people used a 8V golf cart battery and a 6V golf cart battery.

author: Circlotron
author_rank: Super Contributor
timestamp: September 26, 2018, 12:05:52 am
content: Why would it work only with an old fashioned ports ignition system?

author: ahbushnell
author_rank: Frequent Contributor
timestamp: September 26, 2018, 06:23:47 am
content: Quote from: Circlotron on August 13, 2018, 01:14:32 pmyou start constant current then shift to voltage limit as the voltage reaches you max value.
Èast to West on a sloped roof, thin-film, or? - Page 1
Forum section: electronics / general

author: The Soulman
author_rank: Super Contributor
timestamp: August 08, 2018, 11:08:16 am
content: Hi, I'm moving to a different house soon (in NL) and are planning to install solar panels asab.Looking for 5 max. 7 years return of investment, 15 year useable live.The available roof space is approximately 25m2 facing east and 25m2 facing west at about 30 degrees slant, no shade.Apart from a permit that may force me to thin-film on the east side for esthetic reasons:I'm leaning towards thin-film because:*Low cost*Better performance in cloudy weather conditions (ie normal weather)*The higher degradation of the thin film is off-set by the sub optimal placement (not facing south).Is thin-film a logical choice in this case?

author: timh2870
author_rank: Newbie
timestamp: October 12, 2018, 03:10:05 am
content: I also have an East-West roof and chose thin film for the western side because (1) they generally do better [than silicon] in low light or late afternoon conditions, (2) they look better, and (3) they were dirt cheap. $500US for a pallet of 50 panels. The catch is that the company is no longer in business, so it will probably cost more to dispose of them in 20 years than I paid for them now. Thin film panels contain Cadmium, and their future disposal might be a problem here or where you are.