The best photovoltaic solar panels

harold1946 wrote:
Thought I would share some information on what are rated as the best/most efficient panels available.
Sanyo HIT Power N Series.
The cells are hybrids of monocrystalline silicone, surrounded by ultra-thin amorphous silicone layers. It is unique to Sanyo.
Panels are 31.4 by 62.2 inches, generate 220 watts at 5.65 amps, and have a cell efficiency of 19.8 percent.
One of the unique features is that their efficiency increases as surrounding temperatures rise, where most will loose.
They are made in California and Oregon.

It seems like this panel has a 39 volt output at it's rated watts.

So it would require MPPT type controller with a input rating of at least 40 volts, and this will charge a 12 volt battery pack. Yes 5.5 amps input around noon will put out more than 10 - 15 amps to a discharged battery that is running only about 12.8 volts. That is how a MPPT (Maximum Power Point Tracking) controller works.

If that is what you want, and it works out for you, yes it will work great. My question is what is the STC rated watts? That is more a practical real world rated watts, not some lab results from a lab run by the manufacture. If the cost is less than about $2.25 per STC rated watt, it should be a good deal. However you can buy other panels that are as low cost as $1 per STC rated watt, and might be a better investment, even if they take up a little more space on the roof to make a 400 watt system.

SunELec.com has panels in all price ranges, and might be able to beat the price you have on the Sanyo panels - same model number. THey also have some great prices on controllers.

IF I would recommend a system now, (I am planning a system for a church in Hati, we need to raise the funds to pay for everything) I would recommend a 12 volt nominal panel, and 12 volt PWM controller. A Pulse Width Modulation controller might only cost $65 for a 20 - 30 amp controller, while the MPPT controller might be $230 for the same amp rating.

So using the lowest cost per rated watt panels, along with a PWM controller, even though a little less efficient, we can make up for it with a larger panel, and still collect 200 watts per hour X 5 hours average per day.

So compare the cost of 2 each 220 watt Sanyo panels, and $230 controller. mounts, and wiring, you will get a system cost of say $750 - $1250? (I am just guessing)

If you instead use 5 each 100 watt 12 volt panels, a 30 amp PWM controller, and mounts, wiring, the cost might be less. Say around $675. Sure this system will take up more space, but we will have plenty of that at the Church.

So yes it might be worth it to install the higher efficienty panels on a RV roof, where space is only limited to about 200 square feet (with space taken away by A/C units and antenna's and roof vents).

Whatever you decide on, make sure you measure the space on the roof before ordering the panels. Make a cardboard cut-out. It can be difficult to install a pair of 5' X 3' solar panels in a space that is only 8' wide and has sloping sidewalls where you can not mount the panels. Yes I learned this the difficult way trying to install my 120 watt panels, they are in a less than ideal location above the drivers and passenger seats, and cause some wistling, as air going between the panels and the roof. With the other smaller panels in other locations on my roof, and the A/C and roof vents going down the center of the roof, there is not much space for a 40" wide X 5' long panel.

Fred.