tomjasz
1 GW
amberwolf said:It still depends on the BMS design as noted previously--that behavior is what determines what happens in the case of one pack stopping charge for *any* reason while the other continues.Chuckles1 said:I don't know details of my bms, so the possibility of charging safety issues gives me pause. My batteries are UPP brand, so not the highest or lowest quality, from what I gather: dont have a clue what sort of bms they use.
Sounds like the switch is safest way to go, though I'd much prefer a simple "Y" connector if I thought I could charge safely. I wonder if connecting both chargers and switching on both batteries, then activating both chargers simultaneously by using a plug strip with on/off toggle would eliminate the charging safety concerns for a "Y" connector without DPDT switch?
If you don't know which kind of BMS they have, it's possible to check by opening the packs to see if they have separate wiring from the charge and discharge ports to the BMS, so that the BMS has three independent thick wires from it: B- to battery cells, P- to discharge port, C- to charge port.
If P- and C- are the same electrical connection, or there is only a P- with both charge and discharge wires to it, then they are as safe as such things go to directly parallel.
If P- and C- are separate electrical connections, then the problems noted can happen and result in cell damage under certain conditions.
That’s overly complex for the average user and maybe even bad advice. Many packs are so marginally built as to make diving in a potential disaster. Your advice is always spot on but often well beyond average skill level. KISS for me…