Magnum MS2012 inverter/charger. 4- L16 AGM batteries (4 yr old and have all load tested good), and I've run out of things to check. The AC power is run through 6/3 Romex with ground, all connections have been properly torqued and rechecked. Battery cables are all 2/0, and are located only about 3 ft from the inverter. Here the story, I gave my previous (aforementioned) inverter and batteries to my sister for her 5th wheel after upgrading my MH to lithium. Now it won't run the microwave for more than a minute then everything shuts down, (inverter, and remote) the remote shows no faults, and has no faults stored. While running the microwave the remote shows about 130 amps dc and battery voltage gets drawn to about 12.2 vdc and if shut off will immediately rebound to 13.6 vdc if it continues to run after about a minute everything quits. LBCO has been lowered to 9.0. It is really only a few outlets, the microwave, and a coffee maker that will be run, so other than not having to run the genset it's really not worth her spending much money fixing. I have called Magnum tech and they couldn't come up with anything, So I'm reaching out hoping someone can point out that I'm just missing something simple.
Thank you