Reverse current leakage

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.

A hole in my bucket

After two weeks on my window AC unit, I'm sad to report my little panel has not collected enough juice to fill up my Powerpack. The week before I placed the 6 watt panel and Powerpack on my roof. It took 3 sunny days to get a full tank. So this weekend I abandoned the AC unit and returned the team to the roof.

I liked the AC solution because it was so convenient. Just plug in the panel in the morning. Unplug at night. The only thing with the placement....there's a tree and streetlight nearby that eventually cast shadows on the panel around midday. The shadows must be cutting down the efficiency.

After moving the setup to the roof I realized this process is very similar to collecting rainwater for use in an apartment. Sure, you've got a tap that delivers more water in a one minute than you could collect in a week. But efficient collection plus conservation could significantly cut into how frequently you hit the tap. Now it's just a matter of where I place my buckets.

Dirty, dirty, dirty

After three days of good sun this week I was disappointed my battery was still registering an empty status. I've noticed this pack reports only four capacity states, 0% (empty), 80%, 90%, and 100%. But I'm not even getting an 80%. Checking out the panel on Wednesday, I noticed a layer of pollen, dust and other gunk had collected on the surface. Surely this sooty crap has a negative effect on the panel's wattage.



Today I pulled in the panel, gave it good wipe down and set it back out. You can see in the pic the grossness that came off the surface. And this was after a full day of heavy rain!

I'm wondering how people in houses with panels on the roof deal with debris, pollen, bird poo and other detriment that builds up on their panels. Please leave a comment with some insight. Meanwhile, I'll be fishing my panel in and out of my window for some regular cleanings.

No sun = no fun

The weather has been pretty crappy this week with only two somewhat sunny days. My mood and my battery are both running real low. But that's the thing with solar power. No sun, no fun.

So I'm on-grid at the moment contemplating how to scale up so I'm storing more power in a shorter amount of time. Any suggestions or comments are welcome....

Here comes the sun....in about three years

While I've been dinking around with my little apartment panel and powerpack trying to squeak out a wee bit of solar power, researchers in Tel Aviv and Silicon Valley are claiming big advances in solar cell development. From what they say, the cost and efficiency of solar power will challenge typical utilities in about three years. Check it out below.

Start-up: Affordable solar power possible in a year

Researchers claim photovoltaic cell advance

Pulled from Engadget