I have this large, fully isolated, dual conversion UPS which contains 16 12v 7aH batteries, for a stored energy capacity of 1.344kWh. That’s just not enough for me. So I connected 8 12v 110aH in 96v configuration to the “external battery” ports, which gives me 10.56kWh of extra storage. I don’t think they ever intended on this much battery being hooked up there, so I also got a dedicated 96v lead-acid charger to help during a re-charge event. This latest UPS configuration is an upgrade for my UPS systems described HERE.