I have a 12000XP and have recently (last 3 or 4 months) start getting momentary 100% power outages about 1-2 seconds long (not a dip in voltage, this is 100% down, all the lights turn off, all devices reset). It typically happens when my air conditioning starts up (4kw when running). It happens when the total load is still below the maximum but is more frequent when another large power draw is on (4kw for oven or 5kw for the dryer). Tonight it happened when the AC was turning on with no other large loads on at all. I have 55kwh of custom lithium ion batteries with a voltage range of 42v - 48v (the problem doesn't seem to depend on the current voltage of the battery).