My First BMS but mine only has B- AND C- connectors.

[WebmasterHJ]

Hi all, I just built my first 7S pack and will be installing it inside an old24V UPS. I alsobought a 7Sbms which only has the balance wires and B- and C- connectors.

Wondering if I bought the wrong kind of BMS.Is this considered a balancing only bms or how would I connect the UPS positive and negative cables to this so that it balance charges and discharges when my power goes out?

Here's how the bms is laid out. Thank you!

https://imgur.com/a/6XU15Ap

 

[jesusangel]

Hello, first is to ask the seller, but with chinese BMS B- is battery negative and C- is charge negative, so you insert the BMS in the negative cable of your battery.

I supose your BMS is like these:

https://secondlifestorage.com/t-smart-BMS-software-XIAOXIANG


Then connect every cable of the balancing port, if your BMS is 7S you have 8 cables the negative is connnected to the same as B-, or the most negative of the 7S then evey cable to the next positive of every cell or cells in parallel. The positive of the whole battery only connect with the BMS by the balaning cable.

 

[WebmasterHJ]

Hi jesusangel, thanks for your reply. This is the actual bms https://www.amazon.com/gp/product/B07FTK4CG4

It does look somewhat like the one in the link you sent me but on that page there's a diagram that helped me I think. It shows there that the B- connector goes directly to the negative end of my battery pack and the C- connector goes to the negative end of the load and charger which would be my UPS negative then my UPS positive would go to the positive end of the battery pack.

Hope I got this right

diagram: https://secondlifestorage.com/imghost/aqqzbf0.jpg

Cheers