I had my solar panel set up for a couple months now and just started to monitor the power output. Right now I have a 90 watt harbor freight kit, and 2 80 watt mono and 2 80 watt poly panels. All are wired in parallel so it should add to about 410 watts at around 20 volts right? I know voltage drop for battery bank after charge controller. So it converts it down to 13 volts. I have an amp meter wired in series before the charge controller and at peek time I only see it reach 14 amp. 14 x 13 volts is 182 watts I am only getting out of the panels. So I cam losing almost 60% of my potential power output from the panels!!!! Why is that? I thought that the amps do not change only the voltage drop for the batteries, so my meter should read almost 20 amps. Which would be 20 x 13 volts = 260 watts output from panels. That is only around 40% of power loss. I am so confused and not happy with the results I am reading here with the amount of money I spent for all of this. Thanks for every ones time and help.
More Pages:
- Solar Panel: How Can I Set-up My Small Solar Panel To Charge AA Solar-rechargeable Btteries? (5/22/2011)
- Solar Products: Is There A Gadget To Turn Low Wattage Into Large Wattage To Power A Whole Home? (9/1/2011)
- Solar Panel: If The Open Circuit Volt Is 21.5 On A Solar Panel Do You Need A Charge Controller? (9/30/2011)
- Solar Power: Solar Charge Controller Problems? (8/17/2011)
- Solar Panel: If One Small Solar Panel Can Charge 1.5 Volts In One Day? (11/3/2011)

{ 3 comments… read them below or add one }
are you sure that all of your connections are tight? because it sounds like the power is not making it to your battery bank. hope this helps.
I found a good manual on solar panel and solar charger. I downloaded it from ISO Hunt. It gives a lot of information on theory and setting up a solar system.It is titled “Build Your Own Solar Panel” You may want to download it.
If it were me, I’d start by trying to isolate whether it was one or more of the panels. I would disconnect each panel, in turn, and wire it directly across the ammeter. Don’t worry, a short circuit will not damage the panel. My guess is that the Harbor Freight is putting out way below the advertised power. The other panels should have a power warranty on them, so would put out reasonable current.
Also, being that this is winter, are your panels pointed directly at the sun? We lose 30% of our power in winter, just due to tilt that doesn’t match the low inclination of the sun.