Bought my first fiver about 5 years ago. The batteries lasted 2 years, and took a lot of maintenance as in I had to add water every couple of months.

2 years ago I put in a Boondocker 60 amp charger and 2 WalMart group 31 DC batteries. After a year i noticed I didn't have to add much water. I just checked the batteries after ignoring them since last August and they are in perfect shape, (1.290-1.305) and took 5 ounces of water total in each battery.

I'd call that a precision battery charger.

 

The older 5er's didn't have smart charger converters that stepped down the charge cycle like the Battery Tenders and similar chargers. The newer 5er's do. I rarely add water to the two GC batteries in my 2014 toy hauler, and it is plugged in continuously.

 

Ditto that. Some of the stock charger/converters are little more than a transformer and rectifier. Upgrading to an intelligent multi stage unit will both charge faster and drive off less water. Intella power units can be upgraded with a charge wizard.

Stock wiring is often less than optimal as well.