What is Eating Those Batteries?

Ron Nielson wrote:
Mt fiend arrived in Phoenix from Quartzite with a new battery. He stopped at the Walmart in Buckeye, took both batteries in and told them neither battery was working correctly. They checked both batteries with the first test, had him wait an additional hour to run another test and their answer was that one battery (almost a year old) tested 'bad - replace' and they did replace the battery for free. The other battery tested 'good' without further explanation.

So the friend arrives at my house and the PD9260 also arrives at my house in Phoenix and we put in the PD9260. We removed the converter/charger section of his old unit, figured out what wiring went where on the new unit and installed the new unit, mostly in the dark with flashlights. Attached the one new battery he had (the other was being charged on my back porch) and declared the job done.

As it turned out when we tested it today that the job wasn't really done because the charger had no output!! So what possibly could be the cause of that? Turns out that the bat+ cable when inserted into the screw down block of the converter was inserted so far, the bare wire didn't make contact with the converter (screw came down on the wire's insulation) and no electricity was output. Took a while to figure what was wrong, but we did figure it out. And earlier today, the Trimetric 2025 battery monitor arrived. We started putting that in today also while doing some other repairs on the trailer's gray tank. Should be able to finish the monitor install tomorrow.

One thing that still puzzles me is that the battery that Walmart says is 'good' has been on the charger at the 3 amp charge selection for 2 days, much of the time at nearly 16 volts, and the specific gravity is no higher than when we started charging. Is this just the result of sulfation?? Do we keep charging and for how long? When do you just give up? This battery was manufactured in Dec 2013 and purchased in late Dec 2013, so it hasn't had a lot of use, presumably not a lot of abuse either. Is there hope for this battery OR is it time to buy a new one (would have 2 new, non-sulfated batteries), head back to Quartzite or places beyond and trust that with a new converter, 2 new batteries, a battery monitor, that things will work out OK ??