On 2 Apr 2007 02:20:00 -0700, "
wrote:

There would be no load other than keeping the batteries (two, I think 54 Ah each) topped off.

Can someone knowledgeable estimate the float current needed to keep
these batteries at full charge??

The "Self Discharge" rate for lead acid batteries varies by
construction and condition but is commonly quoted at about 40% per
year which translates to 3 or 4% per month.

In other words, a 54Ah battery needs about 2Ah per month to stay fully
charged. Assuming 720 hours per month, an average trickle charge rate
of 2 / 720 amps (about 3 milliamps) per battery should do the job.