Mentioning your batteries are shot probably is from the constant running them down below the 50% charge state and not getting them back up to their at least 90% charge state to burn off the bad deposits built up on the battery cores.
We camp off the grid alot here but did plan out how big of a battery bank we needed to run the things we wanted to have. We watch our batteries real close and will not ever let them get discharged below the 50% charge state (around 12.0VDC level). Then we re-charge them using our smart mode converter/charger being powered by our 2KW generator to get the batteries back up to their 90% charge before using them again. Just running a charge for a couple of short charge cycles may do additional harm to the batteries. We found we need to get to the 90% charge state before start using them again...
I have been doing this 50% to 90% charge cycles since 2009 and my 255AH battery bank is still doing ok. They are just now starting to fall off on performance now.
Just keep in mind a typical 120WATT Solar panel will only give you 5-6 usable DC AMPS to trickle charge your battery bank. Depending where you are you can only expect 5-6 hours of high sun...
I am just now planning to use solar panels to help out in the re-charge of my batteries and want to produce around 20AMPS of usable DC Current while in the high sun. To get my 255AH capacity battery bank started off I will still use the 2KW generator for the first hour of charging and then let the rest of the high sun day do its thing to get my battery bank to its 90% charge state before i loose the high sun. My 255Ah battery bank wants to see around 52-53 AMPS DC Current when first hit with 14.4VDC when recharging... Only my on-board converter/charger can give me this much DC Current being run by my generator.
I like to be able to run a good 20AMPS DC CURRENT load off my battery bank from 6PM to around 11PM each evening when camping off the power grid... Then of course there is also a good 1-2 AMPS being drawn by parasitic drains 24/7...
If we were just running a light or two and living off of candles and flashlights it wouldn't be much of a big deal haha..
Even with my bigger capacity battery bank I still don't have enough available power to run air conditioners, microwaves or long term runs just using the trailer furnace and 12VDC blower.
We actually know not to expect all those lovely things to have when camping off the power grid anyway...
lots to think about for me to make it all successful...
Roy Ken
