BMS Boards, Need some clarification

General Discussion
#1

Hey everyone, I’m looking to use a 4s bms with balancing for a project, pretty much one of these

But with every BMS I’m seeing, they overdischarge protection kicks in at around 2.7volts. Even this one which I see around here alot kicks in at 2.9volts http://www.batterysupports.com/36v-37v-42v-10s-60a-10x-36v-lithium-ion-lipolymer-battery-bms-p-267.html

Im using 18650 cells and I know going that low will kill them, but every bms I’ve found has the overdischarge set to around 2.7volts. Am I missing something here? or do all these bms boards allow the cells to kill themselves.

Thanks everyone

#2

It’s best to manage cell voltage by checking them yourself. Your BMS will let your cells go low so you dont get stranded when you still have power. 18650’s are tested to go as low as 2.5v. You won’t kill them going this low, you’ll just drastically impact its cycle life.

#3

You can customize the LV threshold on VESC.

#4

Bestech Bms’s can be ordered with low voltage protection as high as 3.0v They also sell Bms’s with communication ability that can be connected to a computer and custom programed with software that is included with purchase. http://bestechpower.com/products/

As Jinra mentioned, it is still best to monitor battery voltage. At least with an inline volt meter for the total pack voltage. (with this option, you’ll need to keep a safe margin during discharge)