How about the inverse logic?
Given a $1200 bill and assuming 0.14 per KW hour would mean approximately 8570 KW were used. Assuming uniform usage for the entire period this is about 72 KW per day or 3KW per hour. THen assuming a nominal 120VAC and very simple calculations (no phase shifts ect) this is a current draw of approximately 25AMPS.
The battery failure didn't occur on day one so a much larger draw is required to get to the 25 amp average.
On a side note, wHen my XANTREX is charging at its maximum of 75 amps (indicated) DC the AC consumption is around 12AMPs. Assuming a worst case of 120 days continuously and 0.14 per KW this would be about $580.
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