I’ll be building a 12s pack soon and was wondering if there is a reliable AliExpress BMS or if I should just get a Bestech D140. Also I was curious how can you even test a bms to make sure it’s doing it’s job? Just check to see if the cells are balanced?
I have this one in my new mountain board build and it’s holding up great. The phone app is awsome; it lets you check the individual cell voltages, set over voltage and under voltage levels, and even turn on constant balancing. It has kept all of my cells within 0.03 volts of each other. Be sure to also order the Bluetooth module. I’m using it charge only right now, and charging at 15amps.
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But if you wired the BMS charge only then the only protection you get is over voltage and balancing, under voltage and current protection only works if the BMS is wired in both charge and discharge.
Charge only is fine
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Can you use the standard VESC Bluetooth single?
I run lights and a gps tracker though the BMS. It keeps these from over discharging the battery over a long period of time. Also, I set overvoltage protection to 4.1 volts per cell to help persevere the life of my battery.
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Idk, the Bluetooth module plugs into a uart port on the BMS(I think), so maybe the vesc module would work.
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I also ordered one. It sounds really neat.
It is, it’s really nice to be able to keep an eye on your battery without needing to open the enclosure.
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What charger do you use? 15A is a serious amount of current.
This looks promising. So you purchase 2 separate items correct. Bluetooth + bms. On the bms there are several choices. Which one did you get? Looks like the choices have to do with discharge amps. Which would be bypassed anyways…
Look after these bluetooth bms’s from “JBD battery PCB board store” on Aliexpres. They have the best app / PC software. And the BMS comes standard with bluetooth module. I have one on the way for my gokart battery.
I got the 30A W RS485 UART and the Bluetooth options(two separate items). The charge amps also vary with the current capability. The 30 amp BMS is rated for 20 charge amps.
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This one on Alibaba. I’ve been using it for a little while now and it has held up well. The build quality seems really sturdy, and it doesn’t heat up much. The fan only turns on when it needs to. I’m using it to charge a 12s 15,000mah lipo pack on my mountain board.
Do you have measurements off it? 
It’s huge, I don’t have measurements, but I’ll post a picture for scale
Edit:
Got home and measured it, it’s about: 134x222x67mm
Thanks again dude. One more question. Did the bms come with the balance lead wires or was that separate?
It came with the balance lead connector, and some other wires for uart and the other port.
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Dude.
Do you happen to have the wiring diagram for this? No instructions came in the box… I’m struggling with the internets…
