Right in the middle of our first trip with the inverter, we were cooking dinner on an 1800 watt induction hotplate. After a couple of minutes the inverter shut off and indicated low battery/overload intermittently. The battery wasn't actually low yet and I realized I'd not actually configured the battery settings so I ordered a MK3-USB to configure things (irritating it's not already bluetooth like everything else). This morning I fired up the inverter and it immediately did the low battery/overload thing. I turned it off, plugged in the Mk3 and turned it on again. Nothing. The mk3 can't find it either. Now it won't come on at all - no lights, nothing. The power at the terminals in the inverter when trying to turn it on is 26.8v. I verified there is no drop when the switch comes on. The only explanation the manual gives for this behavior is power either too high or too low.
Is my ~$1300 inverter dead after literally 15 minutes of use? How do I even debug this? I've already fully killed the power and brought it back and still nothing. I KNOW it fired up when the batteries were totally full at 27 volts the first time so I'm waiting for the charge to get back there now but not hopeful.