Hi Leighton - if you want a heavy duty/high amp batt charger that will bring the flatter ones back to life you should have one - and guys here have cited some good ones.
BUT - maybe?? We have 23 vehicles here (17 of them are more than 40 years old) plus some ATVs, and two tractors. Three trucks have dual 12v batts - and one set is huge, in a 52 Mack.
There are ony two of us here, and my wife drives only one of the vehicles and one tractor. So, many sit for long periods until I go do my "go-start-them-all-today" routine.
We do have two fairly good powerful full-chargers but RARELY does either get used. That is because we keep ALL of the sitting batts on smart trickle chargers. The better units read/float and also have a de-sulphating pulse. They cost about $40 each and we can keep a constant full charge on 4 batteries with each one. I also use a few of the Harbor Freight cheaper units (once were $4.99 on sale so grabbed them) and they seem to have been working fine. I use those on ATVs and a small tractor, but do only 2 batts at most with those
At least 7 of these working batteries are more than 10 years old - one is 13 yrs and still working. The key for me has been to keep the batts at full charge all of the time. Where batt charge levels are allowed to go down, and then up, etc. - and if ever allowed to go flat - that seems to kill them earlier.
I go around and check them all once in a while with a meter to be sure (and water as might be needed). If you have only a few batts and can mind the constant trickle charging, you might give this a try - could save some $$ and maybe have longer batt life.
Hope you get some charging from this.
P
