I think SIO2 are an option, but in a very narrow aplication. they are now the most expensive battery by ah as some LiPhO4 are dropping to a little cheeper now. they charge faster but cant handle as many amps as a regular deep cycle battery so depending on your system you may have to get a different charger anyways. there not lighter than normal laed asid, not smaller, just have a higher rate od discharge which can be overcome by adding more cheep golf cart batteries.
if you looking at replacing batteries and can do some simple soldering you can build a bumch bigger bank that charges much faster, can discharge much higher and has a much longer life for much cheeper. the only disadvantage is they need to be above 0 to charge, only to charge they still dischare with less of a loss due to cold when its cold out. but at 1/3rd the size and 1/2 the weight it isnt hard to find a interior hiding spot to put them where the furnace will keep them warm.
it all depends what your comfortable with and how much work you want to do. for my 5th wheel good quality GC batteries have lasted me 14 years, I do have to look at changing them this spring and its a toss up between normal GC batteries again or Li. the price of Sio2 is prohibitive as I would need 5 to get the same AH . I dont size batteryied to use the full range, I size them for shallow depth of discharge so I dont get 400 cycles I get much much more as I am not hitting that point where so much dammage is done, hence me getting 14 years on a set of GC batteries. my majore issue now is where to put the Li (if I go that way ) where they will be able to stay warm foe winter camping.
Steve
