Help with wiring layout , dual batteries


I’m working on adding a second battery to my BKB duo. The Duo comes with a 10S3P Samsung 30Q pack. Charge only BMS

My second pack I’m waiting on is a 10S3P pack made from LG cells, unsure which cell but it has a constant discharge of 20a. BMS is charge only. Pack I purchased here.

Since these packs have different cells in each I’ve been worried to run them in parallel. I have come up with the idea to run both inside one enclosure with a loop key connected to both batteries. Only one loop key will be connected at once ever. So run battery 1 down to around 10% and then switch the loop key to the other port, this disconnecting battery 1 and connecting battery 2. I’ve included my wiring diagram below.

I’ve had some people say I CAN run them in parallel.

Any help is MUCH appreciated.

We had a huge discussion about this the other day on another forum and the consensus was that it’s still not a great idea, and even when it’s possible, the rewards aren’t great.

definitely a cool idea and I think it would would work just fine. Your diagram looks right to me. The only one thing to be aware of is that you should never connect two loop keys into it at once haha otherwise if the batteries are different voltages at all, it will go boom


Thanks for the reply. Im thinking my original layout is what Im going to go with instead of running them in parallel. I don’t feel the benefits outweigh the risks personally. And yes, agreed on only ever one loop key plugged in. Im only going to even own one loop key just so it basically cant happen. Ill also make a dummy connector to work as a plug to cover the port im not currently using. Appreciate the help.