Well, Saturday our car wouldn't start. I tried jumping it with a spare 12-17 Battery, but it wasn't muscular enough to turn over the Toyota engine. Since I use 12V charging in parallel, I had my 12V charger, but even at 10A, is wasn't going to be enough to start without waiting for a charge to accumulate.
Then I remembered that the battery pack for the XB-600 was wired to lead each battery out to the Anderson PowerPole 8-gang pack plug. For operation, I use a series plug that produces 48V. For charging, I use the parallel plug to allow the 12V charger to charge the pack. I used the parallel plug and plugged it to the jumper clamps. Now all four batteries were teamed up.
A turn of the key and VRoom!
XB-600 to the rescue.