HF float chargers

One on each...

This HF #99857 1.5A Onboard Battery Charger/Maintainer's output was cold without a battery connected, a good safety feature if the clips short. When connected to a small, recently charged AGM it went to

14.4V at around 1.5A, then as the battery quickly came up the output dropped to 13.35V at around 100mA, which agrees with the notes I wrote on it after buying it. AFAIK that will top off an unused battery and then keep in good condition without bubbling away the water.

I couldn't find a good place to mount it in the truck with the AC plug accessible but protected from road salt spray so I brought out a fused battery lead to an Anderson that fits through or tucks into a smaller hole, and ran an external charger every few weeks. Thus I have no further experience with it.

14.4V may not be enough to break through the sulfation in a neglected battery, and this unit won't tell you when it's doing nothing useful. That's my objection to commercial trickle and automatic chargers; they give up too easily on older batteries that I can revive with my adjustable chargers. However the setting that brings "dead" batteries back would dry them out and ruin them if left on too long, so I can see why such chargers aren't sold to a general public unaccustomed to minding their experiments.

-jsw