Hugh,
In regards to P.R.’s letter, the transformer on the Pentair Intellichlor reduces voltage from 120VAC or 240VAC down to 22-39VDC@ 7.5 AMPS maximum,, not 12VDC. I see no reason why the Intellichlor could not run without an inverter and transformer if the battaries supplied 24VDC. -TLS