Just be aware that most batteries don't survive going all the way discharged very well. Most of the time they have to be replaced. Charge them back up to full right away and exerise them through a few cycles of 50% to 90% charge states.
It is a good idea to place some sort of DC MONITOR that alerts you when the batteries get to their 50% charge state which is around 12.0VDC.
I watch my batteries like a hawk here as I can't afford to replace them every time they go flat. My DC VOLTs monitor is manual however. I also check the battery fluids on a somewhat schedule... This is the first sign they are not going to survive for you when the fluid levels start boiling out...
My original battery bank was four batteries and I lost one right away in 2008 because I did not have a good smart mode charging system connected. The remaining three batteries have done me well since 2009... I just checked them a couple of days ago as they are still sitting in battery boxes on the trailer tongue completely disconnected. Two are reading 12.4-5VDC and one is reading 12.2-3VDC. This lower one was damaged back in the beginning and has always been the first one to start dropping back. I will wait another week or so and then do a full 100% charge of three disconnected batteries either by running my 2KW generator for several hours (around 12 hours) or running an extension cord out to the parked off-road trailer...
Your other comment about the solar panel not keeping up is a problem here as well. I have a small less than 10WATT model sitting in my truck windshield plugged into an always "hot" 12VDC socket. It does not keep with all of the truck parasitic drains for truck electronics. Works great for about a week topping off my start battery when not using my truck and then starts allowing the battery to start a slow discharge. I have to drive the truck a couple of times about every week or so... My 2KW honda generator lives secured in the truck bed which is covered and locked bed cover and is a great plan B to power up a 10AMP smart mode battery charger if I can't get the truck started sometimes. Also very useful for the sweet old lady standing by her car in the Walmart parking lots too...
We are usually the last ones leaving a campground setup and almost everytime someone has run down down their truck with all the doors open for a couple of hours loading up for travel back home. I can't count the number of rescues we done here with the 2KW generator haha... We get to visit and drink a cup of coffee while my portable 10 AMP smart mode charger is bringing their battery back up enough to start their truck.
Nice to have plan Bs
Roy Ken
