Refurbishing 18650 Cells

[@vevenaneathna]

hmm theres a couple boards which use the ip2368 ic as you referenced (the 100w bidirectional one in greatscots video, also can be set to do lifepo4, and i used to make a cheap power station with 4x 8$ 32ah cells). there are also boards that keep to 1S config but can step up all the way to 20v now and have built in temp protection, no bms needed for 1s. personally i dont trust bms' anymore for these applications, i switched to just using perminate active balance boards, the inductive ones i think are most reliable. caps and mosfets always go bad either from age, misuse, or heat, but its pretty hard to fry an inductor if youre using it within its limits. no electrolyte to get dry/leak like caps. these boards are also much more efficient than bms', which i think allows more usable lifetime charge cycles out of a battery bank (even if one cell starts to loose capacity. it will not completely dictate the total capacity of a series config). imo theyre very beginner friendly. but so many people think you have to use a bms now days.... in my experience, most diy battery fires are from faulty bms'. the car audio world has been using balance boards instead of BMS' for awhile now coz they have a particular set of needs (ultra high ultra short C rate), thats the only other place i have seen this idea online. my 2 ev's run deleted agm batteries and in place have similar 4s 32ah lifepo4 12v batteries now, saves about 45-50lbs, and boosts range from lower parasitic 12v drain/internal resistance. lifepo4 is getting so cheap its making it not worth peoples time to refurbish old lipol cells.... large format lifepo4 cells (280ah) are like 45-50$/kwh right now lol. 18650s would have to be $0.30 each to break even with cost competition now, and cylendrical cells loose to prismatic (even lifepo4) on density because of their steel shell and shape. its a shame we dont make any lifepo4 batteries here in the US yet.

[@BitsOfBoris]

@@vevenaneathna wow interesting input

[@BitsOfBoris]

@@vevenaneathna I don't remember if I mentioned it as I recorded the video multiple times, but as you stated nowadays a battery pack that delivers 230V should be LiFePO4. I was able to get a real 250Wh for 250$ and the price will only go down from there.

[@vevenaneathna]

@@BitsOfBoris hmm not sure on the 230v, maybe need a step-up. my "12v" ~4s 32ah power station fits inside a mini ammo can and has ~420WH of capacity. output is just a fused 25 amp unregulated "12v" dc port which runs my diesel heater or an inverter fine. i used 2 of those ip2368 boards as input/outputs, so it can charge at ~200watts (100w each), or do pass thru, and i keep a 12v 140w accessory/car charger adaptor with buck/boost up to 20v/5a inside the ammo can with cables which can expand the ports as needed for an additional 100w usbc/30w usbc/ 30w usbA the whole project cost about 60$ to build, and i kind of copied the idea from the anker solix dc 300 except i wanted something with double the capacity, half the size, and passive cooling/water proof enclosure. been meaning to finish a video and put it up on my channel. have all the build pics and video of it working but no time to do voice over/edit. nothing like this currently available because power station mfg are sticking to bottom tier cylindrical lifepo4 cells instead of the better prismatic ones.

[@jcthe2nd]

many laptop batterys its only one battery is broken so it shuts down the whole lot including all the good cells

[@jcthe2nd]

yes good advice I have shorted the cell nearly welded my side snips 😂 and I do it I keep cells and have a spot welder to rebuild tool battery packs

[@BitsOfBoris]

@@jcthe2nd I had bought a cheap spot welder in china... But it died on me because the battery has been drained from sitting so long unused. What an irony. And the PCB wasn't even turning on again with an external power source, despite the recommendation of the Chinese shop to short a capacitor on the board. What mess. Not a good experience. Since I never needed to make a custom battery pack.. I never used it. I used 18650 in flashlights, or to power some electronics projects. 1 cell is often enough.