ebay solar panels?

[wanderer-rrorc]

is it safe to buy some of the bigger panels from ebay??

Im not sure if they can handle the vibrations of being on a vehicle...

what makes a good RV solar panel?

[LandCruiserPhil]

Siemens is what I have and they are built very stout and have held up though many miles of wash board and hi-speed forest roads.

[wrcsixeight]

I have a single Kyocera 130 watt panel. I have it mounted on my fiberglass roof of my conversion van. Think frame flex. I have hundreds of miles of Baja washboard, and frame twisting miles on it, and a couple hail storms with dime sized hail.


You don't say what size/wattage panel you are looking for, but keep in mind a lot of the larger panels are meant for home applications. They have higher voltages so that thinner gauge wiring can be used. An RV, needing a nominal 12 volt system usually needs a panel in the 17 volt range. You can use a higher voltage panel, but then you need a MPPT charge controller, which converts the extra volts into extra amps.

I have an MPPT controller, but it is not rated for higher voltage panels above ~23 volts open circuit.

MPPT as opposed to PWM charge controllers basically keep battery voltage from artificially limiting wattage. They can be 30% more efficient at lower temperatures and lower battery voltages than PWM controllers. I usually see about 12 to 18 percent higher output than input amperage.

There are some panels that roll out, and need more space to produce the same wattage as framed panels, but are nearly indestructable in normal use. I believe UNIsolar makes them.

Much more could be said.

[jkam]

I've been looking at some cheap China made portable panels on Ebay.

http://cgi.ebay.com/120-W-FOLDING-SO...item414dc9b717


120 watt briefcase style made in China is about $390 including shipping.
Includes a cheap charge controller and plugs directly to the battery.
I've seen nicer one, better made ones for much more.

[wanderer-rrorc]

im looking for about 170W of power...but since many things have been changed since my initial designs i should rethink my power needs...

[wrcsixeight]

Are you thinking of mounting the panel(s)permanently on the roof?

Are you gonna allow them to tilt? If they do tilt, depending on how they are wired, series or parallel, the shade of the one panel on the other can drop the output of both panels significantly.

If you are going to keep them flat, get 40% more watts than you think you will need.

My 130 watt panel allows me a lot of music from my unamplified stereo, a couple hours of laptop use, exhaust fans 24/7 fridge and unlimited LED lighting. I can tilt it, but usually leave it flat 90% of the time.


Whatever panels you buy, make sure they have the 20 or 25 year warranty, and have operations/ distribution/ servive centers in the US, rather than only in China.

[LandCruiserPhil]

Are you thinking of mounting the panel(s)permanently on the roof?

Are you gonna allow them to tilt? If they do tilt, depending on how they are wired, series or parallel, the shade of the one panel on the other can drop the output of both panels significantly.

If you are going to keep them flat, get 40% more watts than you think you will need.
My 130 watt panel allows me a lot of music from my unamplified stereo, a couple hours of laptop use, exhaust fans 24/7 fridge and unlimited LED lighting. I can tilt it, but usually leave it flat 90% of the time.


Whatever panels you buy, make sure they have the 20 or 25 year warranty, and have operations/ distribution/ servive centers in the US, rather than only in China.

Not always necessary, it depends on where you are located...not much difference in my part of the world. Also if you tilt you need to always point south otherwise flat would perform better.

[LandCruiserPhil]

Im currently using CDT solar panels on a couple of small jobs solid constriuction, good pricing, and they are out of CA.

[wrcsixeight]

My 40% extra recommendation for flat mounting was considering an Ohio location, but is still probably an extravagant number, But better too much, than too little.

Right now In S California with my panel flat on the roof, I get nearly it's maximum rated output(7.39 amps) for about 2.5 hours around noon. But in the winter time I'm lucky to see 6.4 amps when it is flat on the roof.

When It is flat at 5:00 pm, I get around 2.3 amps from it. If I then tilt it at the westerly sun, I will get 6.8 amps out of it. If I am parked next to the ocean and tilt it at the west in the afternoon/ evening, I can get 8.4 amps from it if the winds are light and the sea smooth and highly reflective.

[LandCruiserPhil]

My 40% extra recommendation for flat mounting was considering an Ohio location, but is still probably an extravagant number, But better too much, than too little.

Right now In S California with my panel flat on the roof, I get nearly it's maximum rated output(7.39 amps) for about 2.5 hours around noon. But in the winter time I'm lucky to see 6.4 amps when it is flat on the roof.

When It is flat at 5:00 pm, I get around 2.3 amps from it. If I then tilt it at the westerly sun, I will get 6.8 amps out of it. If I am parked next to the ocean and tilt it at the west in the afternoon/ evening, I can get 8.4 amps from it if the winds are light and the sea smooth and highly reflective.

Thats really cool you are getting that much output next to the ocean. I never would have thought but it makes sense. For future reference what angle do you tilt the panel?

There are a lot of variables that need to be considered when designing a photovoltaic set up for sure.