To switch the whole pack from one 144V series string to two 72V series strings run in parallel, I need 3 connections.
1 very big powerful connection in the middle of the pack that connects the two 72v strings together in series for running, and disconnects them for charging.
Then I need 2 connections are that disconnected for running and connected for charging. They only need to be able to run the current of the charger.
Rather than finding a bunch of switches or contactors, I already have a few spare Anderson connectors. Each connection connects/disconnects two cables at a time.
That means that I can use my existing beefy main battery disconnect as the "middle" connection that breaks the pack in half.
I can use a smaller Anderson disconnect (using both cables running through it) to connect the two ends of the battery packs to connect the two 72v strings together in parallel for battery charging.
The only downside to this whole thing is......DON'T HAVE BOTH CONNECTORS PLUGGED IN AT THE SAME TIME!!!!!
That said, guess what I just did by mistake.....
Glad I didn't pay too much for the batteries!
The good news is that I am just fine! Plywood is great at preventing splattering molten battery post!