for you finding the problem.
for me being right at least once on this forum.
Actually, I suspect that your battery died as a result of deep cycles (severe depletion) probably caused by something else, but once it got to less than about 70% charge it began to fail and contributed to the issue. Lead acid batteries don't like more than a couple of deep cycles and need to be kept at about 80% charge or above to have any sort of life/reliability. I have recently learnt this the hard way. Get a Shorai LiFePo (Lithium Iron Phosphate) battery and you won't look back.
