Noob lipo bms question

Hi all,

I'm trying to resurrect an ebike project I had running years ago, and have some questions about getting a BMS going. Please forgive me for asking a dumb question.

TL;DR: I'm building a 20s2p pack out of turnigy 5s. Do I use 8 5s BMS boards, or two 20s BMS boards?


My aim is to basically make the balancing/charging/monitoring portion of the ebike completely self regulating. I have heard arguments in the past that you can bulk charge, and that the cells won't drift too much. But I don't want to mess with any of that. I just want to be able to plug in 1 plug, and charge it easy peasy. If a cell goes out, I'll just replace the pack.

So, my current pack is made up of turnigy 5s packs in a 20s2p setup using 8 packs total.

My question is, I don't think I can put a 5s bms on each pack right? I need to put a 20s BMS board on each paralleled pack (so two 20s BMS boards), does this sound correct? Also can I use a BMS that is advertised as a Li-ion bms?

Also does anyone have any recommendations for appropriate boards on aliexpress or ebay?

Thank you!

Fewer BMS is always the better option.

I don´t see much point in having two bms. I would just go for one 20s bms and keep the cells connected to each other. Or do you have them as 2 packs far apart or someting?

A single 20s and make all the parallel connections the two strings of cells. Each 2p group counts as one cell then.
Lipo and Li-ion have the same voltages so should be OK.

But do check the lowest-level components occasionally, nothing lasts forever and proactive monitoring reduces any "surprises"

Can you explain "lowest level components"?

I think you're saying occasionally check each individual pack with a volt meter.

Any suggestions for a decent 20s bms?