Choosing a BMS (Beginner- Help needed)

I have a custom battery i will like to add a BMS. At first i wanted to build one but it seem very complicated so i decide to choose one from the market. But i don’t seems to find any website or document on how to choose the right BMS step by step. I was wondering if anyone could me out here as i m missing knowledge on the subject.

I personally don’t think you need a BMS for discharging, and I don’t think I’m alone with that opinion here. I trust good cells and good soldering over a cheap chinese BMS’s current ratings. In that case, your options open up a ton. You still want to balance during charging, but you don’t really care about the discharge rate. At that point, any known brand BMS will do fine as long as you match it to your battery specs, and adhere to it’s charging capacity. I highly recommend getting a BMS you can interface with to get actual readings instead of trusting it to be doing its job. I like the bluetooth capable ones. I picked the one from lithiumbatterypcb, but I hear that daly recently launched one, and I’ve had a great experience with Daly BMSs in the past on other projects.

Thanks a lot i m going to look into it

I have had good luck with ant bms it has Bluetooth can see all the cells on your phone at once
eBay has them aliad etc
I have only used them to keep in balance
I use them for a different use
(They can’t handle the 500a draw I use them for)

But they seem to draw down the battery a bit since they on all the time

Maybe newer ones out there nowdays

How many amps should the bms be rated for I’m going for a 12s12p battery? Do bms need to be cooled?

Depends, do you want to use it for discharging? Or just for charging. If it’s for discharging I would get one rated for about 150, your probably not going to draw that many amps from the battery, but that depends on how you set your duty cycle!

Thanks! yeah, I’m thinking of using it for charging and discharging.