Help!! How much Solar Power needed for a Pop-up Camper

So the wife and I recently bought a nice Coleman E3 popup camper:


So far, we have only been on one trip "off the grid" with it and were surprised at how fast the battery was drained just running the water pump and lights at night. To the battery's credit, I forgot to charge it fully before leaving, but still we were only on day 2 when it died completely. Luckily, my dad had a generator that he was albe to lend us and we were close enough to make it worthwhile to go get it.

Problem solved for this trip, but thinking long term:
1. Dads borrowed generator is loud and way too big for what I need.
2. Buying one of those nice Honda quiet generators would hit the budget hard
3. Gas is expensive and getting more expensive.

We are planning an epic trip to Yellowstone in the camper and Taco for May-June 2013 and the campsites there are all primitive- read no water or electricity- so we need a way to keep the battery charged while off the grid. A little generator would be perfect, but again no $$$ for that in the near future. I got to thinking about solar stuff like the Goal Zero products or solar panels to keep the battery charged.

The company I have researched the most is SunForce but they are pretty ambiguous on how much it takes to fully charge a battery every day. The simple 15 watt models sound like they can trickle charge or be a tender for the battery, but how much would it take to actually charge the battery fully?

So far, I think I am leaning towards getting this:

DuraWolf 37606 65W Crystalline Solar Panel

http://www.amazon.com/DuraWolf-3760...srs=2601531011&ie=UTF8&qid=1349960923&sr=8-92
It is 65 watts and seems to be the best value for watt output that I have found (also has the aluminum frame and impact resistant surface), but I don't know if it will be too much and I am overkilling it, or if it is still too little and won't fully charge a battery.

So above dissertation aside, my question is assuming that I discharge the battery 75% or more each night running lights and water pump, how big of a solar panel (how many watts) do I need to fully recharge the battery in a normal 12 hour day? -My battery is a deep cycle marine battery.

Thanks,
Micah

 

Somebody else will hopefully chime in, but if my math is correct,

65w = 5.4amps @ 12v. Take note that this is FULL capacity of the panel, so we are talkign a clean, properly angled, no cloud hit.

I definitely don't think that is overkill. Not sure, may not be enough?

 

Me again. Just a thought, but some of the bigger trailers can have their batteries charged by the tow vehicle when towed. Maybe this would be a good option to look into as well?

 

Yep, you're math is correct. To take it a bit further, you'll need to know the specs on the battery.

As an example, if you're battery is rated at 55 amp hours, under perfect conditions (as mentioned above), if the battery is 75% dead it would take about 7.6 hours to fully charge the battery. If the battery is dead, it would take about 10 hours to completely charge.

 

So make sure I'm on the same page: 5.4 amps x 12 volts = 65 watts...,

So this panel can charge 5.4 amps per hour under perfect conditions and the amps are what get drained in the battery and needs to be replaced/recharged??

Thanks for the help guys, I will check the amp hours when I get home.

 

Tell me about it...

 

I know that the battery will charge when the main power cable on the camper (big 30 amp plug) is plugged in, not sure if it will charge when hooked to the truck??

 

I have a pretty extensive solar system for our trailer and to power some equipment that the wife and I have for our expeditions. This was the place I started with, good info, pricing not too bad.

http://www.windsun.com/Photovolaic_Systems/RV_Systems.htm

 

Yep, that's essentially it. On a sunny, cloudless day you will most likely have enough charge on the battery for the night.

 

Lot of good useful info on that site. I would also suggest investing in whatever wind-up dynamo things you can find. I have a Kaito thing that is digital am/fm, weather band, LED reading light, LED flashlight, solar charger to run radio or charge cell phones/mp3 stuff & also has temp/barometer/clock. Also have smaller version minus a few features that is easier to walk around with. Also have lantern just for site lighting. Those can be backup to rest of setup or night time battery usage savings.



Sidenote: Diggin the Cepek Torques, kinda wish I had gone with those instead of the AR Fuels.

 

A little off topic, but make sure you check the rules for where ever you decide to go. I recall some of the big parks, not sure if Yellowstone was included, may not allow tents or canvas sided RVs due to the bears.

And very nice camper and tow vehicle, BTW.

 

Thanks, I love the torques and they were among the cheapest 16's I could find... they now come in gun metal grey too.
We have all of our old camping gear including lantern and tiki torches to light up the world outside, really just looking to make sure that we can run the water pump and inside lights for a while, maybe the laptop or built in radio too. The water pump stays on for a bit when trying to wash dishes and there is continual drain on the battery from the CO sensor (not much but there). I'm sure if I could get a big enough panel, I'd opt to run the mini fridge on power too instead of propane.

 

Thanks. Yeah, Yellowstone is very specific on where you can have tents or soft sides. This is the reason we are having to be off the grid, the only campsite that has full hookups requires hard sides b/c of bears... but where we have reservations is only 4 miles away??? I have never heard of a bear traveling over 4 miles to get somewhere.

 

I have a similar camper and experienced the same thing. This got me looking into PV panels and in the process I realized replacing my single stock battery with two 6V golf cart batteries would give me much more capacity for much less. I ended up picking up the batteries at Costco and following the information on this site - http://www.title-3.com/Battery.htm. The next thing to consider is what is draining the batteries in the first place and if there is room for improvement. Switching interior lights over to LED's is a very good start. You will find a lot of good info at the camper/RV web sites on going solar.

 

Doesn't seem like too much involved for what you wanna do based on what I read on that site.

 

I think I found my answers:

http://www.windsun.com/Photovolaic_Systems/rv_solar_faq.htm

Thanks SoCaltaco65 for the original link, +1 for you man.

So I think that my Interstate HD24-DP battery is rated around 50 Amp Hours (which I'll probably upgrade later after this one wears out- possibly urging me to get a bigger panel now).

So assuming the battery is dead, and I buy that 65 watt panel, it should take 9.2 hours to charge. (65 watts / 12 volts = 5.4 amps, 50 AH / 5.4 amps = 9.2 hours)

Or if I buy that huge 240 watt panel, it will only take 2.5 hours. (240 watts / 12 volts = 20 amps, 50 AH/20 amps = 2.5 hours)

I think that might be overkill, but for the price difference, it might be worth it. The 65 watt panel is $210, but the 240 watt panel is only $290 (but the ones in between range up to $350's). I'd still have to get a controller for it, but still cheaper than the Honda generator at $800up + gas (Sorry New_Mexico_Taco). I'll probably get something between, we'll see. I still have about 6 months until we ramp up for Yellowstone.

Edit: Also to stumble, I was so focused on solar, I just saw your post on the batteries. Mine is set up just like that one in the link with a single 12v battery. I'll probibly opt for 2 golf cart type 6v's when I upgrade. Thanks for the link.

 

Another thing to consider is if you camp in a heavily treed area, you will be blocking the sun and reducing the amount of charge.

 

This thread is making me want to plan a trip like that.

We have a very similar but older Coleman that we use a lot. But we rarely stay to far from home and usually stick to the places with hookups.

So no battery on ours other than the Taco battery can run the interior lights if parked close enough to plug in.