Competition Solar 47701 20-Watt Amorphous Solar Panel with 8 Amp Charge Controller and 12-Volt Battery Charger

Very easy to use. I keep a marine deep cycle battery 205 reserve hours (big one) charged for the boat. This is my second Comp Solar 20 Watt panel. Works great all the time. Make sure to mount it securely ( I made some simple brackets so I could use existing holes in my steel building) or the wind will blow it around and damage it.

Doesn’t work.

With these being amorphous cells I was hoping that get some power to a spot on my finca where I have little direct sun largely because up in the mountains most the days are cloudy. I purchased one and like so many others, it came cracked. However, the cracks couldn't be felt on the surface so I applied a thin layer of clear silicone and proceeded.First a little. A maximum potential a 20W cell charging a 12-volt system should produce 20W / 12V = 1.67 amps. I figured under a cloudy sky we might get maybe 0.8amps which is enough for my application. I mounted the cell where it received about six hours of direct sun (or sun behind the clouds) but the battery never seemed to stay charged. The charge controller indicated it was charging, other times it indicated the battery was charged but when I measured it it was only at 12.4 volts. The charge controller wasn't working well so I replaced with with another that I knew worked. Still the battery was never charged. When the controller indicated the battery was charged I could unplug the battery side, plug iit back in and it would then indicate ti was charging. I never saw the battery over 12.4 volts. Maybe this is the cut-out for the controller, but why?I did order six of these to use for another application and when they arrived I connected them to a MPPT charge controller in series to see what they could produce. First of all of the six cells, three of them were broken, two of them so severely that that wouldn't stay waterproof even with the silicone fix. But I did hook three of the panels up to the controller and placed the panels in DIRECT sun on a cloudless day. The three panels, using an MPPT controller, generated approximately 1.4 amps which is only 0.46 amps each at ideal conditions for the panels (they were cool when I took the reading). I also put them in parallel with the same controller and only received 1.19 amps (no surprised since in this configuration the MPPT controller can't harvest the full voltage).A panel this big ought to produce more than an 1 each giving me something like 2.5 - 3.0 amps in bright sun. Bad conversion? Unknown but these panels produce far below what they should. I attached photos of the three panels in the sun on the MPPT controller and the amp reading on the controller. Under a cloudy sky they produce even less - and they should be close since they are amorphous.For the size of the panel you're better off getting a 40W monocrystaline panel then these. Bad deal.

I'm using it as a trickle battery charger on my sailboat. Works fine. Looks well made. Controller included. All connections are plug-in. I compared a lot of 12v 20w panels and controllers and this seamed the best quality/price.

This panel will charge in the dimmest morning and evening light, it turns on around 7am in winter at 37 degrees north. Daytime rates avg about 15-17 volts so it is charging a 12v system perfectly. Looks and feels really well made, metal trim, very thin, easy to hook up with included 7 amp charger... (!, I didn't think it would even really come for this price, but it did!)$50 bucks are you kidding me, this is the best deal currently (2013)I have it in my classroom, with an old motorcycle battery and a 500 watt rms inverter, we charge our laptops, run a radio, fan, basically all the power we need in the classroom. The 6th graders were able to easily set this up in a few minutes and charge my phone, lesson completed.MAde in the USA. Awesome.

Uh, does it do anything to help charge a van battery in full Florida sun? Can it work behind the windshield glass? Do I need to get another one?

Works really good , haven't had any problems keep my battery charged, Really easy to hook up and install.

Was so looking forward to this product but panel can smashed to bits