It's always hard to keep the batteries up on equipment that sits for long periods. I found a solar battery maintainer/desulfinator that's working well for me. Solargizer from Pulse Tech like these: (I don't sell these, just examples I've found online) https://www.ebay.com/itm/274330466964 https://www.easternsurplus.net/PartDetails/7209/ALL-5225-24V-Solar-B... These two are 24v that I'm using on my D6c dozer and a 5-ton military truck but there are 12v models. Direct from the company they are a little pricey but they can be found on eBay and other places for much cheaper. The military uses the 24v versions so can be found surplus. For the dozer I stick it to the top of the brush guard with magnets, and when running the machine I pull it off and stick it under the canopy to keep from tearing it off with tree limbs.
When I worked for the local Cat dealer we bought four of the twelve volt versions. I used them on the small machines, skid steers and mini excavators. The small machines had no master switches and were always going dead. When a machine was sold, we just moved the chargers to a different machine. It saved a few batteries and a lot of jump starting. I did the same thing with magnets.
I use 2 of the 12 volt ones on my trackhoe, just one on each battery. I have been using them this way for 5 or 6 years, and they work great, even though the alternator is weak. They are just the $9.99 specials from Harbor Freight. I am going to have to look at the 24v ones.
I am new to this solar battery charging. I previously had purchased a 25 watt 12 volt panel. I decided to build up a charger for my D6B 24 volt system, so I bought a second 12 volt 25 watt panel to wire in series for my 24 volt system. After doing some reading today, I decided that I need a charge controller with the 25 watt panels to keep from overcharging my batteries. Glad I ran across this thread as it got me to reading some more.
It would be nice to find one with some indicator that it is working. Don't forget to remove charger before driving tractor..........don't ask how I know.
These have worked well for me. https://hardkorrlighting.com/en-us/product/15w-12v-or-24v-trickle-charge-solar-panel/
AS LONG as you got 1 or 2 volts going into the batteries then you should be fine but if its going to sit like 4 or 6 months then for sure check the water level before cranking em up
Krackerjack9, I'm sure you meant 1 or 2 amps. Working on my maintainer as the parts come in.