Evolve Bamboo GT BMS help (is BMS fried?)

After browsing through previous Evolve GT battery upgrades on this forum I tried doing it myself. Everything was going smoothly until I hooked up my balance wires to the BMS and the BMS started getting too hot to touch. When I noticed this I immediately disconnected the BMS but now Im unsure whether it’s fried or could still function. I redid the wiring and checked the voltages on the balance leads and they seem to be in order but the same problem persists when I connect the balance plug - the BMS gets hot. Any troubleshooting suggestions?



IMG_20181001_215311 (upload://x886j4TKwbHbPXM05aPPmycxo7M.jpeg)

It could be that your cells are out of balance and its balancing them. That would get the mosfets warm or hot. Maybe @psychotiller could shed some light?

Thanks for the reply, I hope that’s the case. Thing is, the board won’t turn on either, so I’m guessing I still did something wrong. I’m pretty sure the balance leads are ok now since I double checked they were hooked up correctly (going from B0 to B10 starting from left to right seen from BMS viewpoint) and had the right voltages.

The BMS weirdly only gets hot on the right side though where you see the cylindrical thing with the volt measure on it (yeah i’m new :P), you can see the orange “glue” being burnt there as well. I’m guessing if it was a BMS balance plug problem, then the heat would be concentrated there instead.

I checked again and the BMS also gets hot when the positive discharge cable is connected so I’m guessing it’s just normal and I was overly cautious. Unfortunately, I still can’t get the board to turn on. Here is another pic. Anyone tell me where I might have gone wrong?

IMG_20181002_002540 IMG_20181002_002628 IMG_20181002_003039 IMG_20181002_003028

If the bms is getting too hot to touch, there’s definitely a big chance your cells are different voltages. Did you check all of them before you welded them together to make sure they were the same?

Also I’d triple check that your balance wires are in proper order.

I checked the cells before welding they were all 3.4x. I’ll check the balance leads tomorrow again as well. Hope I get this thing to work :slight_smile:


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Can you confirm that the 1st wire on your balance lead (The wire before number 1) is going to your number one group? should basically be connected to your neg terminal.

Yep, the BO wire is basically soldered right on the bigger B- wire on the negative terminal of group 1. Thanks for the suggestions, I’m checking everything again after work.

So I checked the bms wiring and one wire as loose and I replaced it. Unfortunately, the BMS still gets hot afterwards, so Im just gonna redo all the wiring in the weekend, no rush. Thanks for the advice!

Make sure all the balance wires are in order and when you are done soldering then check the voltages from the balance lead cable itself just in case.

If all of those wire turn out to be in order, My on;y other sugestion is shorten all of the wires. They seem really long.

Also make sure that if ur balance wires have an extra wire attach it to ground.

Can you elaborate, I’m not sure what you mean.

So I checked the balance leads and they read fine, thing is when I check the voltage at the bms 11 pin plug, I can’t get a clear reading half the time. Urgh gotta say the start was fun but this last part of building a battery is an exercise in frustration

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Is the 11 pin 0v

I redid the balance wiring yesterday. New wires and soldering. Before that I checked all the battery group voltages - they are all 3.45 or 3.46. After soldering the balance wires to the groups, I checked the balance leads to make sure that each balance lead was 3.4x higher than the balance lead of the previous group. Then I attached the balance wires to the plug and measured the voltages inside the plug - all good. Except when I insert the plug in the BMS it immediately starts getting hot again. Will upload new pics tonight. Hope to get this sorted.

@darkkevind I know you did tons of these upgrades, do you see anything wrong in the pics? Or have any suggestions to get it working. Any help is much appreciated. IMG_20181010_181357 IMG_20181010_181329 IMG_20181010_181315 IMG_20181010_181412

Sounds like one of your balance wires is in the wrong spot. I forget how the balance order goes on these, but I think the right most wire on the balance connector is the negative, and it goes 0-10s starting with that lead. Let us know the voltage of each wire on the balance connector.

I tested the wires, from left to right it’s B0-0v, B1-3.43, B2-6.86, B3-10.31, B4-13.75, B5-17.2, B6-20.6, B7-24, B8-27.5, B9-31, B10-34.3 red wire is B10 IMG_20181010_210334

This isn’t looking good.

Also you should manually charge that a little bit (connect charger to B0 and B10 while monitoring) so they’re around 3.65V each. That’s a bit low for comfort. If it sits around too long, it will creep down as well.