This scooter battery would not charge or discharge. Nothing looks burned yet. How can I test the components to find the failure?
>>2888781Use that there mutimeter to check the cells and make sure they’re not dead. Have you done that? Lithium BMS won’t charge most times if the cells are below like 2.0V for any of the paralleled sets. If they’re good, follow along the output wires and see how far you can go before the voltage stops. Hook up the charger and follow that part of the circuit and see how far it goes. Use continuity to test fuses, ohms for resistance. As for the little computer chips and transistors, wait for somebody smarter than me to explain it.I’m surprised there’s no power coming out of it. Normally there’s not a whole lot of circuitry coming out of the batteries to a high drain motor besides some sort of fuse. And if that were the case, it would still charge. So make sure your cells aren’t too flat to charge as the first step.
>>2888781How many volts is the scooter rated for and how many cells are in there?
>>2888783I can get power if I connect directly to the 38 volts at either end but the actual output terminal seems to be current limited to very low. The two output leads at the right side test 38 volts but putting a load on it pulls the voltage low like its dead.
I discovered something.
>>2888795What is the battery rated overall for? Make sure you don’t have a real low pair, often times it’s either the first set of last set. Like all the way to the right and left, you might have to test that final + or gnd that you’re getting the 38.5 from and one of those balancing wires.Might be crap on the bottom of the board too which would require desoldering
>>2888797Might not be the issue if it’s clean on the other side. But if there was moisture in there, you should take a look at the bottom of the circuit board.
>>2888850>>2888795I think you missed one measurement. It looks like a 10s3p pack, meaning 10 series of 3 cells in parallel. So totally charged you shoud be at 41v-42v. Half charged around 36V, dead is like 25V.If the 9 you measured here >>2888795 are all 4.1V, that’s 36.9V, and if the meter is accurate and you measured correctly, it means that the last set is 38.5V - 36.9V so 1.6V. It often seems to be the first or last in series that gets discharged fast, I’m sure somebody will explain.Measure the ones I circled here. If it’s 1.6V. that’s probably your issue. If a single one of those 3p sets falls below like 2.0V, it often goes into a safety brick mode,
>>2888781I had a ebike battery that would not charge, opened it up started testing battery banks found 3 or 4 bad banks. started replacing batteries found even more, gave up when half the batteries were bad.
>>2888897That’s a bad idea anyway. You’re not supposed to mix and match cells like that or it will be unbalanced really quick.
>>2888858I get 3.2 volts at those two points.
I desoldered board and there is more of that corrosion.
>>2889143Let me guess, you rode it through the rain/washed it on the bike because the chinese manufacturer claimed it was sealed and waterproof?
the charging circuit is probably fucked
>>2889137If you measured at all the right spots, then it’s not the corrosion on the cells.You’re sure it’s not the scooter itself? Did you ever check the voltage at the output plug going to the scooter?
>>2889169>You’re sure it’s not the scooter itselfI used another 36v battery for the scooter and it works fine. When I plug in the charger the light stays green and the battery does not charge.
>>2889192Well since it’s desoldered, you might have to jump a couple things. But you gotta find out what pins are on the connection between the scooter and battery. Hopefully it’s just +, -, and a temp pin. Make sure the resistance on the temp pin is within spec because a bad temp sensor will stop charging and discharging. And then if no power on the + and - on the plug going into the scooter, then try to figure out if there’s continuity on the + or the -, and if you have a good + on the pin going to the scoot but no -, or the opposite, follow that back and see where it cuts off.And then go to the electronics threads and ask them. I’m too lazy to circle a bunch more things to test.
>>2888940well thank you captain sparky. but I tested the capacity of the remaining cells and found them to be about 2200mah. I then went through my stash and rounded up all the ones that were of the same rating. but I ran out and am too cheap to by them.
>>2889143you have 6 packs of 6 cells, if one battery in any cell is dead or dying it will drag all the other ones down with it.the cause of this is that about once a week you need to let the packs sit on the charger for 48 hours to properly balance.to find the problem ALL the tabs need to be removed and ALL batteries need to be check out of circuit. then the remaining batteries have to be checked for actual capacity and replacement batteries of that same capacity put in place.you might as well just buy a new pack.do you own a spot welder? no? then buy a new pack.
>>2889251If it’s something you don’t care about, then whatever. But batteries are all different, even if they’re the same rated capacity. You could have two different brand 2000mAh cells, and one is better with high discharge work, so if you’re using them on cordless yard tools, one cell will have a useful capacity of 1900mAh in that high drain tool and the other one is 1500mAh at those loads, and it will become unbalanced quite fast.And another thing I noticed after taking shit apart, but I need to test more to confirm… you would think the balancing wires are there to add a little extra current to the cells which are low, right? At least that’s what I thought so each bank of cells will always charge to 100%. But I think most of the time, those balance wires do nothing but tell the charger to shut off when the highest cell reaches 4.20V and tells the tool to shut off when the lowest cell reaches 2.50V or 2.00V. It’s retarded because it will always allow packs to become unbalanced, but I guess companies are banking on the cells staying balanced enough to survive through the warranty period. So any little difference in charging or discharge efficiency adds up quick. I think that’s why those M18 12.0 packs and shit always have that issue where they only charge up to 3/4 and then the charger shuts off. One or two banks of parallel cells gets low, so now the charger brings one bank to 4.2V and stops, bank 2 is 4.0V, 3 is 3.8V, and bank 4 might be 3.6V and 5 is 3.2V for whatever reason, so the total pack voltage is 18.8V out of a max 21.0V and it will never get to 100% charge without taking the pack apart and using a power supply on the low cells.
>>288925210 packs of 3 cells*3 cells paralleled, and a series of 10 of those. So battery capacity is 10x the voltage written on a cell, 3x the amp-hour written on a cell.
