Bob F wrote:
I'd love to find a schematic or any other available information on
this device. Mine never goes into the red LED "charge" mode.

Just to put it on the record.

This unit charges a pair of 12V 12AH SLA batteries.

The problem with mine turned out to be a failure of VR2, which went open
circuit. Replaceing it (480 ohm with a 500 ohm pot)solved the problem.

This charger seems to be a be a two stage charger.

VR1 adjusts the maximum charge rate, and should be set to 3 amps when the
charger red LED is on.

VR2 seems to set the level at which the full current charge ends, the red LED
changes to green, and the fan turns off. and the voltage then remains level at
the voltage determined by VR3.

I currently have VR3 set for 28.8V, and VR2 making the switch at 28.6V. I would
appreciate comments on these levels.

I assume that I should limit the total charge time to half a day or so to avoid
overcharging, since this unit does not seem to drop the voltage for a float
charge.