Just a thought, after reading several of the recent tech issues threads - could the Harbor freight Carbon Pile load tester be of use in this situation?
i.e. hook it up to the battery as a 75A load - then you wouldn't need to run the batteries down as low for your testing.
a) this may be the same as your microwave test
b) the carbon pile tester may not handle 75A for long periods of time - It says to run short tests (15 sec), but at lower amps can it be run longer without damage?
I've got a similar issue - a champion 3500/4000W non-inverter that bogs/dies when I run 2 1500W electric heaters on it. I'll open a new thread on that sometime - I don't want to hijack this one.
