Hi all!
I dismantled 3 garden tool battery packs and salvaged about 300 cells (Panasonic NCR18650PF and CGR18650CG). Many of them have rust on the insulator rings and some were damp when I opened the packs.
Should I replace the insulator rings, or is the rust just cosmetic? Which cells would you discard right away?
I've ordered a 4-channel capacity/IR tester. Any tips on how to test this many cells efficiently?
I found used laptop batteries at my work.
Quick update on my battery build from my previous post.
I made custom outer sleeve from 1 mm polypropylene sheet, shape around the pack profile. Its amazing that even cheap packing tape grips the PP pretty well. I'll reinforce it with fiberglass tape when I get it.
My next steps:
Fishpaper over the exposed nickel
EPDM around the perimeter and BMS installation
Mount it all inside a frame triangle bag with EVA foam for cushioning
Still work in progress. The current shell is mainly for mechanical protection.
Curious of what you guys think so far!
I recently salvaged some cells from my old project. Have been charging them on and off for about 2 weeks and 1 cell refused to go over 4V. Other cells are reading 4.18V to 4.16V, just this one cell that refused to go back up. What should I do with it?
Just finishing off a rebuild of one of my 10S4P Reention RK4-type batteries for my ebike, 36V/20A output. It vexes me that after neatly crimping and heatshrinking the whole build, there seems to be no way to terminate the ends of the pack other than dumping a huge amount of solder onto a nickel tab? Something like a spot weldable crimp lug would be perfect but it doesn't seem like they exist other than small ones for BMS leads, is there any better way of doing this?
So I've been working on this BMS for a few weeks now using online research (it's my first time making a battery pack myself, also I didn't use any AI) and so far it's been going well. I haven't got access to a spot welder so I used these cheap amazon cases to solder them. The wires on them were kinda thin so I used some UK mains cable I had lying around for the main series connection and the thin ones for balancing. However, there were no solder points on the cases, so I had to kind of wedge the wire ends into the spring and the other contact. I charged all the batteries to ~4.25V with a "smart" charger I got on ebay. The batteries were of course all connected to the BMS board which I also found online, and the output of the BMS was connected to a buck converter which is activated by a switch I added.
I tried it out last night when the batteries weren't all at 100% and it worked fine without issues. But when I connected them up today and flipped the switch, smoke started coming from all the case joints, so I turned the circuit back off.
Anyone have any idea how to fix this issue? I know it's probably the shoddy case joints, but do I need to buy new solderable cases? and can I still use these batteries? They seem to be fine now.
P.S. this is my first reddit post, am I in the right place? also please don't clown on me too much for my ass setup
Need help!
I haven't found any batteries that fit my criteria of what I need and I am wondering if this would work, and if it does then I want to know the idea I need to have to create this properly.
I'm hoping that the 3 cells of 18350s gets me 11.1 volts and 1600 MAh when it's all put together. Is this kind of idea feasible?
Hello!
I am currently in the process of designing and building a fixed-wing FPV aircraft, and I have gotten to the point where I need battery packs.
I am a complete newbie when it comes to building battery packs, but I have quite some general electronics experience.
My goal with this aircraft is endurance, and that has narrowed it down to Li-Ion cells, probably 21700s for capacity. My motor is rated for 25A, so I figured I will have to build my pack to handle 30A at least accounting for servos, VTX, FC etc.
For now, I have not made any purchases related to the battery pack, and that is what I wanted to ask about:
I will gladly take any other tips and/or recommendations!
Hi guys, I bought this ebike with the intention of repairing it.
The last owner left the battery without charging for 1 year and a half. The ebike is from 2022
36v 10s 4p. All group voltages are from 0,4v to 0,7v and one giving 2v.
Question, should I try to charge it, connecting the charger with out the bms until 3v?
Or you think is dangerous??
After way too much planning, CAD, nickel testing, ruined wraps, current-path overthinking and spot-welding drama, the pack is finally welded.
14S5P, 70× 21700 BAK 50E cells, pure nickel, built for my custom e-bike project.
I also made proper solder tabs for the main + and −, with a second nickel layer and insulation underneath, so I don’t have to cook the cells when attaching the main cables. There’s a tab on both sides of the terminal group to spread the current better.
Still need to install the BMS, balance leads, main cables and finish the 3D printed enclosure, but the part I was most paranoid about is finally fucking done.
Very happy with how clean it turned out!
If it safe to use a unprotected wurkkos or sofirn 18650 battery in a Fenix PD35R? I just got the light the other day and have a couple spare button top batteries but on their website it says you should use protected batteries. But when I look it up it says the light has built over discharge protection. I always like to have spares and don't want to spend $60 on 2 new Fenix battery's if I don't have to
trying to rebuild Milwaukee battery pack, and I made a hole thru the nickel with the spot welder, the cell underneath was not punctured. there are 4 welds alltogether, should I just redo that weld or leave it as is?
i dialed back the power and it seems to perform better no sparking
I finally decided to add a spotwelder to my toolbox of electrical doodads and testing apparatus! I'd appreciate advice on this kit I put together. The BMS says it's rated for 30 amps, but that probably needs a heatsink on the mosfets since I measured a 130mv drop across them for a 7 amp load, they were getting warm.
Should I add any more insulation before dropping it into the case? It's a tight fit and I don't want to pry it back out....
Getting 4.45V at the output. Cells are all 3.88V. Pack is 3S.
If I connect to my power supply set to 12.4V it draws 150mA but doesn't seem to wake up.
I bought a 12v 3S 18650 battery off Aliexpress and after a lot of tests, im pretty sure it doesnt work, the terminals report 11V, I had a charging module that doesnt charge it at all (0 current drawn), the charging module was able to power my motor, the battery also doesnt power the motor at all. where can I get a 12v 3s 18650 battery 3000mAh or similar? And is it possible to repair this battery?
I have a build planned for a stationary battery for a solar charging station using EVE C40 LFP cells and have had everything I need except the actual cells for some time, just didn't expect it to be this hard to get the cells.
I'm in the UK and was looking for an EU/UK source and saw that nkon.nl is often recommended, and they were a decent price at 7-8 euros a piece but they were sold out with a note about stock coming in on sept 18th. I waited but on sept 18th the notice just disappeared and when I contacted them they said they don't have a new lead time on them right now.
I checked elsewhere and people are selling them for like 30 euros a piece, even the dreaded aliexpress isn't much better. At that price it's not really worth using them, I'd have to just redesign the pack around a different cell and maybe even go for a bulkier LTO build with those 40-45AH yinlong 66160 cells that are obviously pulled out of electric busses.
Anyone have any insight on why this is? Is it a normal thing for the market for a cell to just dry up, and should I expect it to clear up or just pick a different cell?