Average Reviews:
(More customer reviews)*Update* 6-2010, while my original panels are still running strong so long as I hose them down once a month, I've noticed that the PVC pipe provided to hold them in place has become brittle with sun exposure, hence I would now in 20/20 hindsight recommend a coat of Krylon Fusion Dover White Plastic Satin Spray Paint on the PVC parts to prevent UV cracking later in life. I do not think the Krylon Fusion product was available when I first setup my first panels but UV cracking of the support structure could cause panel damage in years 2 and 3.
Meanwhile Amazon got their hands on some obsolete & discontinued Sharp panels (12.5% efficiency vs the new 13.1% efficiency) - if you are serious about needing lots of solar power in a small space, this is a big kit - you can view it here: Sunforce 39126 246-Watt High-Efficiency Polycrystalline Solar Power Kit
My only concern about the kit is that due to the new panels being higher efficiency means it will be difficult to match panels if you find you still need more power later on. The other con on that system is it's price -- $1300+ but you get the wattage, along with a cheap charge controller and inverter, both of which could be upgraded for better system performance. It's just another solar system to consider in the $5/watt or less pricepoint for DIYers.
Update 9-18-2008 - Still going strong. I am very pleased with the summer power output of these panels. I wash them with a hose 1x/mo to keep the output current up. Measured before washing and after washing the panel efficiency is clearly a factor of how much dirt is on them. No problems long term on a roof though!
Update 2-20-2008 - goes with graph "photograph" #3 above - pink line is power and blue line is amps from the panel x 10 to share the graph. The X axis is panel voltage. Data was acquired using an Agilent dummy load with programmable voltage in 1V steps from 1V to 22V (open circuit voltage on the panel) on a partially cloudy day in winter sun. Expectations are for 2-3 times performace in summer sun provided the panels don't get too hot. These are on my house roof laying flat on a 3/12 pitch facing due south which is suboptimal but easy for me to do. Be sure to read the photo notes. Sorry about the colors excel defaulted to!
This is a MPPT chart (maximum power point tracking) - you can see that the panels are optimized for charging a 12V wet cell right out of the box. Charge current turns on when battery voltage drops down to 13.0 VDC and turns off at 14.2 VDC with the supplied charge controller in the kit.
The only other interesting fact in 2 months is to keep your panels clean. My maximum current was 5.0 A on a cold morning with bright sun until it rained hard and washed the panels clean. The current went up to 7.0 A maximum right after the rainstorm. Below is the original review - these panels have been running constant for 2 months now into 3 parallel deep cycle marine cells (315 AH) connected to the prosine inverter below to drain the energy made.
When reading the power/current chart you should keep in mind the amps have been multiplied by 10 so they use the same Y axis (so 20A on the chart corresponds to 2.0 A panel current) Watts are actual volts*amps. This was taken in the winter with partial clouds - expectations are for a X3 improvement during summertime but its still february and I'm in the northern hemisphere so we'll have to wait and see. Basically an MPPT charger won't gain but a few watts with this panel so it's not a good investment unless you already have one laying around.
(Begin original review after buying panels)
I never seem to be overwhelmed by the latest shipment of product from China, but this one seems to show some promise and shows signs of good cost engineering and a complete design that can be set up quickly by one person with very little effort. I'd give it 5 stars if it were well packed, but my purchase turned into a shipping fiasco.
Most ALL solar installations are rated in $/watt much like new homes are rated in $/sq ft. We'll get to the sq ft bit later. Here you are getting 60W for 320 dollars or about 5.33 $/watt. Compared to a similar wattage panel, the BP solar 365U rated at 65W and priced (street) at 399 or 6.13 $/watt the amazon package seems to be a good deal when you consider it comes complete less battery (we'll hit that one later too)
In fact, the amazon package deal includes a xantrex 175 watt inverter with a .15A "idle" current designed for solar systems where current consumption must be minimized. It even includes a simple diode/switch "charge regulator" with 2 leds to indicate panel voltage and battery is full but lacks the ability to tell it what type of battery you are using (full is defined at 14.2 volts give or take so it's for wet/flooded cells). Neither of these are big buck items, but they do set you up for a complete small scale solar kit minus the battery out of the box, which is impressive.
Oh yes, the battery. I also ordered the duracell 480W inverter+28AH battery with this panel so I'd have a battery. Also made by Xantrex, it's a nice piece to complete the system. I made the mistake of ordering it with the solar panels (read on)
So how does China produce a complete kit for a lower $/watt price than professional solar companies like BP solar, GE, Kyocera, etc? Well - it's the sq ft part we forgot about for a while. This uses 4 panels @ 15W each to get up to 60 watts with a simple parallel adapter included in the kit. The BP solar is one panel about the size of 1 of these 15W panels, or put another way, is 1/4 the sq footage. So if you are planning on covering your roof with these, think again because you'd need a really big house and have lots of 7A charge diodes and 175W inverters kicking around when you are done. The reason for the 4:1 size difference is the China panels are made using a silicon deposition on glass technique with a very thin film and correspondingly thin output, while other manufacturers use a silicon wafer production method that is roughly 4x more efficient in area, and somewhat more expensive as a result.
Ok - now onto packaging. We need to get this from China to Amazon and finally to the consumer. On the first attempt FEDX carefully placed my fragile glass solar panels on the concrete then put 2ea 60lb batteries on top of them, cracking the glass on all 4 panels. After returning that to amazon, we tried again, this time without the batteries and shipping the system by itself. FEDX again noted shipment damage which wrecked 1 of the 4 panels, but running on 3/4 panels it does work, just not with full output. Amazon has given up because they will only ship and ruin something twice instead of making fedx pay up for piling 120 lbs of batteries on top of the glass panels and poking through the box & styrofoam the second time so I am still in negotiation with them about the shipment, however the product does deserve mention while I have it.
PERFORMANCE:
The design is actually quite well done. You can make (with 4 panels) a 12V (actually 15V) x 4A system, or a 30V x 2A or a 60V x 1A configuration depending on your power inverter and battery collection. For me, this will always be tied into a 12VDC bus so it is fine as shipped, but the flexibility is there if you have other voltages in use. There is no skimping on wire with 16 foot cords on each panel which helps to minimize power lost in the wire since each panel has its own cordset going to the combiner, after which runs are kept short. On a cloudy day I was able to get 2 amps from 3 panels (30 W) - in full sun it peaked at 5.91A with 3 panels, so the Chinese manufacturing has under-rated their output as 90W from a 1/4 dead 60W panel in winter sun is doing very good - I'd like to know how it performs in the summer!
As for mounting, a very clever system was designed to support the panels out of 1" PVC tubing with elbows and T's - all of this is assembled with a singular bolt/wingnut style and the pipes have slots milled into them to ensure that the panels will line up one way or another without breaking after you get them. It has a prop-up leg system for use on the ground or can lay flat if placed on a roof that is already angled towards the sun. There isn't a provision for connecting multiple systems together, however you could make one out of sprinkler pipes you probably have.
All this really needs to be a well designed solar kit is 1) better packaging and 2) a battery. Even with 25% of my panels broken and removed from the system, it still managed to charge a car battery in under 1 cloudy winter day.
I'm impressed with the product, however disappointed with the shipper. I've also run up against Amazon's policy of two strikes and they are out meaning they won't negotiate for repair or replacement as the shipper on my behalf. I can return it alltogether or pay 100% for 75% of a system so it's probably going back tomorrow (monday) - but my testing this weekend has shown that the product warrants consideration for people who
A) Need to keep their starting batteries charged year round (2nd cars, generators, etc) outside where AC power is not convenient.
B) People lacking A/C power somewhere and would like to run a small refrigerator (purchase a Xantrex Technologies Prosine 1,000 to 1,500-Watt Power Inverter #1000 TRUE SINEWAVE power inverter to run any motor load without damage) - for 12V refrigeration needs its best to AVOID both inverters and peltier...Read more›
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