anyone here using solar panels to charge?

91xlt

Adventurer
been thinking about setting up the small solar panels to charge battery for camping. would like some input as to what kind and how they work. i camp all year, every type of weather, curiuos if they would be worth installing or if they would only work on those picture perfect days i read about in magazines?:sunny:
 

elcoyote

Supporting Sponsor, Overland Certified OC0004
We do a fair number of panel set ups for our trailers. When it comes to the output of panels we only count on 70% performance because rated outputs are based upon full sun and accurate placement of the panel towards the sun. It is good to know how to apply Ohms' law to your power requirements to evaluate your needs: Amps x Volts = Watts
Lets say you decide to hook up a 20 watt panel to your battery bank and you live in AZ where you can count on an average 6 hours of full sun daily. Here's what you could reasonably expect on the low end:

((20watts x .70 efficiency)/12 volts)) x 6hrs= 7 amps.

On the high end;

20w /12v x 6hrs = 10 amps

Remember that your battery is essentially a fuel tank that has a maximum capacity rated in Amps. Hooking up a solar panel to a fully charged battery without a charge controller could cause overcharging of the battery that will shorten it's life.

A very good book has been written on RV electrical systems and covers solar panels. It is written in lay person's terms and is an easy read. I got mine from Amazon.

RV Electrical Systems by Bill & Jan Moeller

Good luck amigo!
 

flywgn

Explorer
We have a Kyocera 120 and a K60 (space limitations) on the roof of our ATRV with a RV Power Products Model 2000E Charger Controller/Booster. During our entire trip to the Arctic Circle last August/Sep I never had to use the genset to re-charge the five (yes, five) deep-cycle batteries on the trailer.

This is overkill, but I like to err on the positive side. When we set up our solar system on the house in Baja six years ago we determined what our 'needs' would be, figured out the number of pv panels/batteries and doubled it.

Mario gives excellent advice above. I have that book he mentions and I do recommend reviewing or purchasing a copy.

If you're wanting to only maintain your vehicle battery over several (many?) days of non-engine charging, a small pv panel/charge controller is all that's required. If, however, you have a 12v fridge, a blender for you margueritas, a couple of exterior 12v lights (flourescent or LED of course) for the campsite, then you'll have to increase your pv wattage. That book is an excellent guide.
 

Jonathan Hanson

Supporting Sponsor
Good advice above, all of it.

If you expect to maintain a charge for long stationary periods while running an Engel or other significant loads, you'll need to look into 100 watts-plus of real PV capacity, and, as noted, a simple charge controller, since uncontrolled charging of Optima-type batteries is not good. If you just want a small system to extend your time between running the engine, you can get away without it, as Scott does now with his dual flexible panels.

The many hours of sunshine in Arizona are great, but also keep in mind that panel output goes up significantly in cold weather. Cold and sunny is best.
 

BajaTaco

Swashbuckler
On a related note, we had some discussion on how to figure out your power requirements in this thread, which may be useful in trying to determine how much solar you want to go for.
 

91xlt

Adventurer
thanks for the input, i do understand ohms law, but will keep an eye out for the book. also my intentions are, i have a trailer i use with a single battery for now. but what i would like to do would be install 2 with some sort of charging system, i have seen the solar set ups at boating supply shops. i now just charge up a few minutes by hooking back up to truck for a while each night, but that is sometimes easier said than done. thinking that by using a solar charger i could simply set up and possibly not worry about it.
 

elcoyote

Supporting Sponsor, Overland Certified OC0004
Here's a look at the dual set up in the nose box my own trailer if you need some ideas. The little black box on the right hand side is a Shell RV-20 charge controller, the inverter is a Xantrex 1500 and the batteries are Lifeline AGM group 31 making a total of 210 Amps. The solar panel I use is a Unisolar 64, it plugs into an socket on the exterior of the box.
 

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Scott Brady

Founder
I have been quite satisfied with the Iowa Thin Film panels I am using, though my mounting configuration showed its limitation in the winds last weekend.

The system generates 40 watts at 15v under perfect conditions.
 

Ursidae69

Expedition Leader
expeditionswest said:
I have been quite satisfied with the Iowa Thin Film panels I am using, though my mounting configuration showed its limitation in the winds last weekend.

The system generates 40 watts at 15v under perfect conditions.

Powerfilm now makes a foldable 60 watt panel. Looks like a great option for someone not able to have a permanent mount. The unit is pricey though, around 1300 for this setup.
 

fisher205

Explorer
I've been considering the foldable collectors to first use by themselves and with a permanent mount collector. The problem I see with a permanent mount is that in the summer, I try to park in the shadiest spot I can find. With the foldable, you would then be able to place it out for optimal sunshine. I would be interested if anyone has experience with this. - Brad
 

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