Sizing solar panels

flyfisher · 09-18-2011, 11:05 AM

I've checked the forum and if this topic has been discussed, I sure can't find it.

I have a 2005 SMB with the penthouse roof. I'd like to add a solar panel to keep the house battery topped up while I'm camping for more than 3 days or so. The house battery is a Lifeline AGM 4D and reefer is the biggest draw. It's a small Norcold, Norcold says this will draw about 3.5 amps/hour.

I don't run any other appliances, just lights for a little while in the evening, and the furnace if it's chilly.

Any help on sizing a solar panel would be appreciated.

thanks..

Tom

**BroncoHauler** · 09-18-2011, 11:17 AM

I think there are a few threads about power usage and appropriate solar panel size, but I'll just offer that I have a single 120W-130W panel, which has been just fine for me. I have about the same usage requirements as you do.

Herb

**daveb** · 09-18-2011, 02:32 PM

I agree with Herb that a 130 is a good size. Alot depends on how much sun is available in the areas you plan to visit. Overcast or fog reduces the output and that's where a second or larger panel can make a difference. Same with tree cover. SMB has also made panels that tilt so you can aim towards the sun. I carry a portable 65w flat panel but rarely use it.

Dave

Ford_6L_E350 · 09-18-2011, 03:40 PM

Our Norcold refrigRuns less than half the time, so the power needed from a solar panel is reduced from what it would be if the refrig ran continuously.

Before solar, we could camp 2-3 days on our 2 group 27 batteries. We added the solar panel (Kyocera 135W) and are quite happy with it. Only in a heavily shaded campsite in Yosemite have we needed to charge the batteries when camped. Other than that, camping for a week or more is not a problem

Other than the refrig, we sometimes watch movies on a small DVD player/TV. The 135W is plenty for us.

Mike

saline · 09-18-2011, 04:01 PM

Another satisfied 135 watt user here.

RickL · 09-18-2011, 04:55 PM

Sportsmobile has a good web page full of info on how to size a solar system:

http://sportsmobile.com/5_sys_solar.html

Rick L

flyfisher · 09-18-2011, 05:53 PM

Thanks all! And a big Dope Slap to me for not thinking to check the Sportsmobile Website.

Tom

**BroncoHauler** · 09-18-2011, 06:08 PM

Quote:

Originally Posted by flyfisher

Thanks all! And a big Dope Slap to me for not thinking to check the Sportsmobile Website.

Tom

Actually, I find some satisfaction that people check here first, and then the SMB website.

dhally · 09-19-2011, 10:08 AM

I noticed all the people who replied were from California or Colorado. The OP is in Seattle. It would be interesting to hear about experiences from Seattle or other PNW locations. The latitude, weather, and tree cover could make a difference.

Tapatio · 09-19-2011, 04:36 PM

Quote:

The latitude, weather, and tree cover could make a difference.

I recently installed a 200w Sovello solar panel which outputs 8-9 amps in direct sunlight. I just got back from a 4 day trip in the southern Sierra's and it kept up with my electrical draw. I was getting approximately 4 hours of direct sunlight per day with partial shading for 8 hours.

My calculated usage:

Code:

                               Amps/hour      Number of hours        Total amps
Refrig. 3E - 2.7CF             2.5                  16                40 
LED lights                      .3                   5                 1.5 
Espar D5                       3.0                   2                 6 
Water pump                     4.0                   1                 4 
CO2/CO detector                 .1                  24                 2.4 
Blue-Sky controller             .017                24                  .4 
Total                                                                 54.3

Picture of campsite, driver side was facing east.

http://www.sovello.com/en/products/p...configuration/