You can use about any battery you like, if you have a DC-DC converter
in the charge controller lineup. I'd base my selection on what you have
for the final stage (intertie or local-use AC inverter
, is my guess). You
will probably find more support for 12V (automotive) and 48V (telecom)
if you are looking for a 60Hz output. You will not lose much efficiency at
a 4:1 stepdown ratio with a buck converter. I expect that you can find
plenty of telecom-market DC-DCs to pore over.