Not a bedwetting condition, reverse current leakage can drain a solar charging system's batteries at night or when the solar panel is shaded. I don't know the details, but I understand the absence or even partial shading of sunlight actually causes the electrical flow to reverse. This would explain why my solar panel was not effective when placed on my AC unit. There's occasional shading and of course a good amount of nighttime to deal with.
One solution is to use a blocking diode
to allow the current to flow in only one direction.
Most charge controllers
provide this protection as well. A while ago I purchased a Morningstar SS-6
charge controller for $44.00. Rather than wire up a blocking diode, I decided to introduce the charge controller into my mini-system.
Here's where I made a big mistake.
I previously followed the Xantrex manual's instructions and wired a DC connector to my 6 watt panel and plugged it into the AC charger input.
Thinking about, it seems strange that this would work....DC to AC? But it works just like the manual says it does.
Following this logic I clipped off the connector with enough lead wire to connect it to the battery connections on the charge controller.
I then wired the solar panel to the charge controller.
Plugging it into the Powerpack did nothing.
No charge...no indications.
Apparently the AC input on the Powerpack cannot handle the DC current coming from the charge controller. This makes obvious sense. But because I had successfully wired up the solar panel to the AC input, I gave this method a shot.
The correct way to do this is to use the DC/DC charging cable that ships with the Powerpack.
I clipped off one end...
...and wired it to the charge controller. The wire connected to the center terminal is the positive connector. When connecting to the battery connections of the charge controller, this connector should be wired to the positive terminal. My cable had white printing on the positive wire and no printing on the negative wire.
I then plugged the DC charging cable into the Powerpack at its DC power socket. The Xantrex manual states that recharging the Powerpack via DC will not light the charging status light. This was inconvenient considering I wasn't too confident I was doing this correctly. However, after draining the battery to 90%, I set it up to charge on my roof. After a half day in the sun, the battery was back to 100%. I'm assuming the charging setup was done correctly. I'm going to use it like this for a few days to make sure.