Solar Panels

NaViDa wrote:
Solar cells can either be poly-crystalline or mono-crystalline, poly meaning many and mono meaning one. Generally speaking, a mono-crystalline solar cell is more efficient by giving off more wattage when the sun hits the cell. As an example, a 100W panel using mono-crystalline solar cells gives off 96W while a poly-crystalline gives off only 93W. The lower wattage is due to losses through wiring and the inverter. The tradeoff for this greater efficiency is that mono-crystalline solar cells tend to be more expensive.

This quote is way off-base. Any 100 watt panel puts out 100 watts no matter what it's made of. The only difference will be the size. A more efficient panel will be smaller. Mono-crystalline will be slightly smaller than poly-crystalline.

smkettner wrote:
I would not even buy that for storage use only.
Get 80+ watts and a decent controller for best results.

If you expect the solar to recharge the battery while camping I think you need closer to 200+ watts or 50w to 100w per battery.

Forum Members Solar Installations With Pics

Here are some panels to compare price.

Before you buy make some cardboard templates the size of the panels. Get up on the roof and make sure they fit. Need to have 12"+ from things that give shade. Check shade at 9a and 3p. Even one cell part shaded can reduce the panel output significantly.

Mono-crystalline seems the way to go and to buy 2 panels with each over 100 watts 12volt. I live in Las Vegas, Nv., so getting the right amount of sun where i'm at wont be an issue.

YOU all are AWESOME here!

THANK YOU!

smkettner wrote:
I would not even buy that for storage use only.
Get 80+ watts and a decent controller for best results.

If you expect the solar to recharge the battery while camping I think you need closer to 200+ watts or 50w to 100w per battery.

Forum Members Solar Installations With Pics

Here are some panels to compare price.

This is what i just read from the website you thankfully provided.

Solar cells can either be poly-crystalline or mono-crystalline, poly meaning many and mono meaning one. Generally speaking, a mono-crystalline solar cell is more efficient by giving off more wattage when the sun hits the cell. As an example, a 100W panel using mono-crystalline solar cells gives off 96W while a poly-crystalline gives off only 93W. The lower wattage is due to losses through wiring and the inverter. The tradeoff for this greater efficiency is that mono-crystalline solar cells tend to be more expensive.

So why would anyone buy "Poly-crystalline" if i'm reading that "Mono-crystalline" in the end will save us more money?

I would not even buy that for storage use only.
Get 80+ watts and a decent controller for best results.

If you expect the solar to recharge the battery while camping I think you need closer to 200+ watts or 50w to 100w per battery.

Forum Members Solar Installations With Pics

Here are some panels to compare price.

Before you buy make some cardboard templates the size of the panels. Get up on the roof and make sure they fit. Need to have 12"+ from things that give shade. Check shade at 9a and 3p. Even one cell part shaded can reduce the panel output significantly.

I have a small sailboat with 100% LED lights, depth sounder/chart plotter, and occasional charging of vhf radios/phones/laptops via 12v plug or inverter. No running water, no heat, no fridge. Basically I'm not burning much electricity. I have a single group 27 12v battery and a 20W solar panel with PWM charge controller. We can go out for a week or 10 days and keep the battery fairly close to 100%. Before I switched to LEDs it was nip & tuck whether I could go more than a week without finding a charger somewhere.

With an RV I'd be *very* surprised if a 15 watt panel would be enough to do more than maintain ONE battery while the rig is in storage. Depending on what the draw is for your propane leak alarm and anything else that uses a trickle of power when the battery is hooked up, it might not be enough. It's definitely not enough to boondock.

hmknightnc wrote:
Hi and welcome to the forum. The system you are linking is nothing more than a battery maintainer (it will not charge even a single battery from any state of actual depletion). FWIW I use 30watts on a boat as a battery maintainer.

The size of your solar system directly depends on your planned usage of the system and storage capacity (number and size of batteries) so can't give you a real solar size need estimate without a whole lot of additional information

Generically to have a useful solar system for RV minimal self sufficiency you are looking at 100watts solar and twin 6volt batteries as a minimum which might get you to being able to do a weekend without electrical hookups. Personally I have 265watts solar and twin 6volts. This allows me to do 3 day football tailgating without hookups. If I were looking to be truly self sufficient I would start with 2x that (batteries and solar size) and add as necessary.

Okay, where do you recommend i buy them at ??

and what about this deal?and what about this deal?
http://www.ebay.com/bhp/12-volt-100-watt-solar-panel

thank you!

Hi and welcome to the forum. The system you are linking is nothing more than a battery maintainer (it will not charge even a single battery from any state of actual depletion). FWIW I use 30watts on a boat as a battery maintainer.

The size of your solar system directly depends on your planned usage of the system and storage capacity (number and size of batteries) so can't give you a real solar size need estimate without a whole lot of additional information

Generically to have a useful solar system for RV minimal self sufficiency you are looking at 100watts solar and twin 6volt batteries as a minimum which might get you to being able to do a weekend without electrical hookups. Personally I have 265watts solar and twin 6volts. This allows me to do 3 day football tailgating without hookups. If I were looking to be truly self sufficient I would start with 2x that (batteries and solar size) and add as necessary.

What are you trying to do? Charge "a" battery?