Customer Reviews

20 Watt Black Frame Mono-crystalline Solar Panel and Battery Charger

5 star:		(4)
4 star:		(5)
3 star:		(0)
2 star:		(1)
1 star:		(0)

 

 

Don't expect 20 Watts from this product. This is the second purchase of the Extreme Power Corp's 20W Solar Panel. The first unit did not meet the specifications defined on the label attached to the rear of the panel so I purchased this second unit to determine if the first unit was faulty. The second unit performed the same way. Here are the details:

I tested the two units at 1000W/Sq. Meter in the sun (Calibration by Davis Weather station solar sensor) at 25 degC and 55 degC into a resistive 16 ohm load (VPmax/IPmax). Here are the results, spec. values in parenthesis:

Open Circuit Voltage 19.4 volts (21.18V)
P Max at 25deg C - 16.5 Watts (20 Watts)
P Max at 55deg C - 12.8 Watts (Not specified but usual operating temp)
Voltage at Pmax - 14.45 at 55 deg C (17.5 at 25 deg C)
Short Circuit Current at 55 deg C 1.0 Amps (1.33 Amps at 25 deg C)

I reported these resulte to Extreme Power Corp but there has been no comment. Two points to bear in mind. 1. - There is a tendancy to overspecify solar panel performance and 2. - Specifications are for performance at 25 deg C and no solar panel operates at this temperature.

The maximum power output under any load conditions that I can get from these panels when cool (immediately after exposing to the sun) and at 1000 W/Sq. is 16.6 Watts.

In operation do not expect more than about 14 Watts from these panels - if that is ok then the product, although misprepresented gets a pass.

John Beukers
2009.05.19

Location:
K55, Baja California, Mexico

Purpose:
Reduce dependence on buddy's noisy & smelly gas generator during weekend trips to beach shack. Week of rest after every usage.

System [June 2008]:
-> 60W total [~3.5Amps]. Two 20W [18Vmp] panel & two 10W [18Vmp] panels of the same mono-crystalline construction. [16AWG]
-> Morningstar MPPT 15 Amp Charge Controller. [14AWG]
-> Two [2] new 12V ~100AH deep cycle batteries [parallel ~200AH, 1/0AWG]
-> 700W AC inverter [4AWG]
-> 3.5KW gas generator to 6Amp AC batt charger for extra charging capacity when needed

Current Load:
-> Three [3] 12V x 26W fluorescent fixtures
-> Two [2] 12V x 15W fluorescent fixtures
-> One [1] 12V x 11W fluorescent fixture
-> One [1] 12V x 13W fluorescent fixture
-> Yamaha 2.1 speakers, 25W
-> Dual-port 12V car cig lighter adapter for mobile phone/iPod chargers.

Notes:
Panels are fixed @ slight SW & angle of ~35° from horizontal due to wind concerns, more than output, but very close to local latitude of ~32°. I was at the Baja house when the winds started the raging fires in SoCAL [2007], it was bad.

Voltage reads 20-24+V @ 3.4-3.6 Amps pre-load between 10:00AM & 3:30PM in June. Current load is lighting- OFF & ON 3-4 hours per night. Usually only one or two is ON at any given time. Lights work very well, almost like normal house. iPod is self-powererd to Yamaha 25W 2.1 speakers on inverter for 2-6 hours during day. Currently, we must use generator for TV/movies/games.

Expansion:
Another 20W panel for 80W total went in Dec 2008- another 80W will conclude a 160W system. Goal is 3 to 4 times per month...lighting, music, & occasional 26" 60W LCD using 15W DVD player & 25W 2.1 speakers for movies when surf is flat. [~700-800 Watt-Hours/day]

The panel took about a week to arrive; the packing was "wierd" (bubble wrap wrapped
around the cardboard! ) but it was intact.

The frame is aluminium, however the backing is plastic and the front side is glass
(not Tefzel). The whole thing is sealed with copious amounts of silicone rubber.

The wierd part of this panel is that it's _not_ exactly a 12-volt panel. In
full noonday sun, it puts out 20 volts open-circuit, at 1.03 amperes. This is
somewhat higher in voltage and lower in amperage than many would prefer; you will
need a charge controller at the very minimum as this _will_ cook a 12-volt
battery if used for a long time. Be sure your charge controller can handle
it- most charge controllers are rated for 16 to 18 volts input and this panel
puts out 20 volts or a bit more.

The panel comes with a pair of 6-foot wires (with something written on them
in Chinese), one red, one black, and permanently attached to a box centered in
the back of the panel. The other end of the wires go to a pair of alligator
clips, but as warned above, don't just clip these onto a lead-acid battery
for long term use unless either the battery is really big or you have a
charge controller.

A downside: lead-acid batteries typically charge at 14 volts; any additional
voltage is wasted. So, this panel loses about 30% of the energy produced
if the charge controller is not an active (buck-boost) or maximum power point
tracking (MPPT) controller.

On the up side, the 20 volts open circuit stayed pretty solid even when
the sun went behind clouds; what dropped was the amperage (down to 0.2 amps
when the array was shadowed, down to 0.1 amp when the sun was _behind_ clouds.
But the voltage stayed up, which means that even on a cloudy day your panel
will get something into the battery, maybe only 10% of a good bright day but at
least something. I think (but am not sure) that this is because it's a
monocrystalline panel.

I like this product. It is simple. Out of the box in early January in northern Illinois I got 15-16 volts and 0.2 amps from this panel. That's what I expected for this latitude and time of year. I'm relieved to have exactly what was advertised on the Amazon website. I just wanted a panel to charge up a 12V battery and see what I could run on it. By all descriptions this panel should work, we will see. For the money, I have not seen any other panel with a 20 watt peak output.

I purchased four of these solar panels. Three of the panels worked correctly right out of the box. The fourth one did not work, and upon some inspection, I found that one of the solder joints to a wire was not soldered. The solar panel had no power output. I repaired the solder joint myself, and now the fourth solar panel works correctly. Overall, I am very satisfied with the way these panels function. In the sun, they perform as expected. I will probably buy more of these solar panels in the future and would recommend them to anyone wanting a compact, powerful solar panel.

Monocrytal panels are the best and last longest. This is an excellent price and is the cheapest 20w panel I've found. Get 'em while you can.

This is a good quality solar panel for a good price. I bought it to keep the batteries on my electric gate opener charged, and it does the job, even in the winter. It met all the specs and is well built ...

I have this unit mounted atop a Jazzy wheelchair and controlled by a HQRP, 10 amp 12/24 (also available on Amazon, as are most of the DC craft tools (like Proxxon) this combo powers). It powers activity accessories (laptop, craft and jewelry tools, lights, and displays). At some point I hope to add another and toggle the wiring so that it continues to power the twelve volt batteries that power the activity accessories and the Jazzy wheelchair 24 volt DC system as well. It is a solid device, well sealed and esthetically fitting to my needs. I did add plastic to the frame joints, because mounted at eye level on a sculpture the corner joints left something to be desired.

I'm very pleased with the performance of the panels and with the way that they look. They perform quite well in portable applications and this is why they come with alligator clip connectors installed from the factory. Works great for charging batteries in diesel generators, car batteries, and even charging a deep cycle battery bank during the day for running a laptop at night. If you're planning to run your whole house or do something substantial with solar power, get yourself a solar array with 120 watt or higher panels wired in parallel in a 12 volt system. These portable solar panels are good to tinker with so you don't have to tinker on very expensive solar array systems that are better left un-tinkered with.

Item arrived in record time and in good condition as of this time it is functioning as advertised. I would recommend this company to others and would order again myself.