I have two Lipo4 batteries in my camper. I tried connecting them in parallel and only one works.
I installed a 1,2, 1&2 switch and still only one will charge while the other actually discharges. I can use or charge either one separately but not together. Both batteries are Humsienk 100ah and purchased near the same time. Both pos cables are the same length.
Any ideas?
They probably have controllers built into the batteries which are not playing nice in parallel config.
I’m not sure how you ended up at this forum.That’s not really what we do here.
But there may be some people that can help
Links and pictures are always going to be more helpful
Off the top of my head, sometimes lithium batteries have smarts built into them.
I was just recently using some that require one to be set as a master and the other (s) to be a slave, and they are connected by a network cable, i haven’t checked the specs on your specific batteries, but this might be worth checking out.
The built in BMS could be causing the issues.
Have you searched some RV forums?
A voltage mismatch could also be the issue, and BMS related
Try disconnecting both batteries put both of them on charge seperately, bring them up to the exact same voltage.
Plug them back in.
let us know
Specs and pics might help. Are they both the same base voltage? Both charged to the same voltage? What are you using to charge them?
And it may sound like a silly question but a surprising number of people get it wrong: Are you sure they’re actually connected in parallel?
Diodes?
Lipo or LiFePo4
We’re going to need battery model numbers, datasheets, specifications of the switch, a schematic of your wiring, and any additional information that you can provide.
Otherwise, giving useful advice will be rather difficult.