solar power and dry camping

[motoboss2002]

Hi,

Just want to be prepared here. Our used pup has a Interstate HD-24DP battery. Not the most powerful, but that is what it came with when we bought it. We managed to get reservations in Yosemite valley for 1 week around July 4th - been there many times before but always in a deluxe all self contained bus type RV. As most of you know, the sites in the valley are bare bones,meaning no hookups whatsoever. Now my question.

I don't really want to go the portable generator route (Honda eu1000i,...)to make my battery power stretch. I'd much prefer going green and explore solar.

Costco has a 18W panel + charge controler on their website for $14O. I realize that does not provide a lot of juice, but will it suit our purpose? We've been avid tent campers, so we don't use electrical stuff like a coffee pot, a microwave etc.

Will an 18W solar panel do the trick and manage to top off/keep the battery in good shape for a week of camping with frugal use? Frugal to me means absolute minimal use of lights and furnace, use of water pump for showers though. Any insights very welcome.
 
Tnx, Christian.

[wavery]

Hi,

Just want to be prepared here. Our used pup has a Interstate HD-24DP battery. Not the most powerful, but that is what it came with when we bought it. We managed to get reservations in Yosemite valley for 1 week around July 4th - been there many times before but always in a deluxe all self contained bus type RV. As most of you know, the sites in the valley are bare bones,meaning no hookups whatsoever. Now my question.

I don't really want to go the portable generator route (Honda eu1000i,...)to make my battery power stretch. I'd much prefer going green and explore solar.

Costco has a 18W panel + charge controler on their website for $14O. I realize that does not provide a lot of juice, but will it suit our purpose? We've been avid tent campers, so we don't use electrical stuff like a coffee pot, a microwave etc.

Will an 18W solar panel do the trick and manage to top off/keep the battery in good shape for a week of camping with frugal use? Frugal to me means absolute minimal use of lights and furnace, use of water pump for showers though. Any insights very welcome.
 
Tnx, Christian.

The short answer is...."NO".

18W (1.5A) is enough to maintain the battery while not is use. It is useless for charging the battery while in use.

a 48W may help you extend your battery in full Sun.  I wouldn't consider going solar with anything less than 100W and 200W would be ideal IMO. Even then, you are at the mercy of mother nature.

A charge controller is not needed for anything under 100W, while you are using your battery. It would only be necessary if you left the solar panel charging for 2 or more days without using it.

100W is only 8 amps. Just think of putting an 8 amp battery charger on your battery for 6 hours a day. That's a 48A charge. That's about what you would expect from a 100W solar panel. Remember, the solar panel only puts out the rated amount in direct, full Sunlight.
An 18W panel will give you just slightly more than the normal discharge of a battery while not in use. You would be lucky to get 4A of real charge a day.

[JimS]

I agree with the above post.  Here is a link to a writeup on the system I installed: http://www.arveeclub.com/showthread.php?t=63953.  I also did a couple of other writeups as well after using this system.  It is in the Dry Camping section.  Just scroll down and you will find them.
I just got back from 4 days in Death Valley and using the lights as much as I wanted and the furnace at night, (temps in the mid 40's) the batteries never got below 90%.
Here are the other links:
http://www.arveeclub.com/showthread.php?t=64247
http://www.arveeclub.com/showthread.php?t=64509

[ForestCreature]

We did have a 15 watt panel at one time. And yes it did keep up as our battery use was minimal...so long as the days were clear . If your use is not minimal and there are cloudy days, it will not keep the charge up . (altho we did survive a 3 week outing on 15w, plugging in once in the middle of the trip)

We now use 45 watts and that does keep up just fine for our needs. Both are of the same make as what you are looking at, ICP and the panels performance has been great to date.

[tlhdoc]

Just a different suggestion.  Take a second deep cycle battery along.  For long trips I take 2 or 3 deep cycle batteries.  When one is getting low I switch to another.  I leave the battery on the tongue for use last.  That way I have a full or mostly full batter for the trip home.  If the break away brake switch has to be activated there is power to use it.

[wavery]

Just a different suggestion.  Take a second deep cycle battery along.  For long trips I take 2 or 3 deep cycle batteries.  When one is getting low I switch to another.  I leave the battery on the tongue for use last.  That way I have a full or mostly full batter for the trip home.  If the break away brake switch has to be activated there is power to use it.

Now.....that's the best idea yet.....cheapest too.

['tiredTeacher]

The short answer is...."NO".QUOTE]

Yup. To go solar you need to spend almost as much money as your trailer cost including a bank of storage batteries in case you have 3-4 overcast days in a row. I'd revisit the generator option.

Incidentally, I saw a set up where the owner put the generator in the capped bed of a pick up, had an ouitside air intake blower and muffled exhaust outlet. He ran an el-cheapo home generator and no one could hear it. Sweet!

['tiredTeacher]

Now.....that's the best idea yet.....cheapest too.

I have two on the tongue.

[wavery]

The short answer is...."NO".QUOTE]

Incidentally, I saw a set up where the owner put the generator in the capped bed of a pick up, had an ouitside air intake blower and muffled exhaust outlet. He ran an el-cheapo home generator and no one could hear it. Sweet!

I do that same thing in the bed of my pick-up with a Honda 2000. I could run it all night long, right next to our bunk and we can't hear it. More importantly, our neighbors can't hear it. :sombraro:

[austinado16]

I do that same thing in the bed of my pick-up with a Honda 2000. I could run it all night long, right next to our bunk and we can't hear it. More importantly, our neighbors can't hear it. :sombraro:

I really like these threads about solar power and I'm very envious of the JimS system!  Wish I could afford to step up!

[Jim K in PA]

As you can see, with solar, there is not cheap way to get a functional system.  An 18W panel is not really worth the money or effort for a camping application.  Put that $140 toward a savings plan for a bigger system.

It certainly would be cheaper than solar to haul around three Deep Cycle batteries and swap them as they discharged, but it certainly is not easy!  That's an extra 150+ lbs to haul around, as opposed to about 30lbs for a 100W solar panel and controller, with cabling.  If you are towing with a pickup or other vehicle with excess capacity and storage volume, go with the batteries.  If you are like me and somewhat limited in extra space, go solar.

The key to building a successful system is to add up your real world daily AH use, and build a solar system that exceeds it by at least 25%. That way you can get through some less than ideal weather and still replenish your battery(ies).  Of course, if you have the misfortune of taking a long trip "wet" camping without  alternative power, your panels will not keep up.

JimS did a nice job on his setup.  I have been trading email with AMsolar regarding their 100W setup.  Based on my calcs it will be more than I need for dry camping, and I should be able to get it done for under $1000, excluding batteries.  I will be upgrading to a pair of matched 6V batteries this spring, and hopefully have the solar setup by fall.

[wavery]

As you can see, with solar, there is not cheap way to get a functional system.  An 18W panel is not really worth the money or effort for a camping application.  Put that $140 toward a savings plan for a bigger system.

It certainly would be cheaper than solar to haul around three Deep Cycle batteries and swap them as they discharged, but it certainly is not easy!  That's an extra 150+ lbs to haul around, as opposed to about 30lbs for a 100W solar panel and controller, with cabling.  If you are towing with a pickup or other vehicle with excess capacity and storage volume, go with the batteries.  If you are like me and somewhat limited in extra space, go solar.

The key to building a successful system is to add up your real world daily AH use, and build a solar system that exceeds it by at least 25%. That way you can get through some less than ideal weather and still replenish your battery(ies).  Of course, if you have the misfortune of taking a long trip "wet" camping without  alternative power, your panels will not keep up.

JimS did a nice job on his setup.  I have been trading email with AMsolar regarding their 100W setup.  Based on my calcs it will be more than I need for dry camping, and I should be able to get it done for under $1000, excluding batteries.  I will be upgrading to a pair of matched 6V batteries this spring, and hopefully have the solar setup by fall.

Don't wait to buy the panels until you have the $ for the ideal set-up. You really don't NEED a controller. Try using the panels without one for a while before you decide on investing in a controller. All you need is a cheap muti-meter (to keep tabs on battery voltage) and clip on cables to attach to your battery. In the unlikely event that the batteries get to 14v, either unplug the solar panel or switch your fridge to 12v (while the Sun is up) and save the propane.

My guess is, you won't be seeing 14v while you are camping unless you leave the camper all day or your battery bank is too small. Even then, if you come home at dark, the batteries will be back down.

The only thing that you need to do is unplug the solar panels at night.

A 100w array will give you a maximum input of about 50A on a sunny summer day. You could get a little more if you move the panels every hour or 2 to better face the sun.

[mike4947]

The major failure of solar for most folks is the word "sunny".
Either you make the panels portable or you have to park the RV in the sun where the panels will be in the sun.
We always recommend doing a LOT of research before investing.
Looking at the actual outputs from solar depending on geographical location and mounting orientation can be eye opening.
 
Here's a few sites to look at:
http://www.backwoodssolar.com/ We especially like their hard copy catalog as it contains quite a few education pages for those of us that prefer hard copy as in "library reading material"...LOL.
 
http://howto.altenergystore.com/
 
http://www.windsun.com/
 
http://www.amsolar.com/education.html
 
and the charge controller page at AZ WindSun we feel does an excelelnt job of explaining charge controllers: http://www.solar-electric.com/charge_controls/solar_charge_controllers.htm

[Jim K in PA]

Mike and Wayne both added some useful points (for those still reading yet another solar thread).  

Wayne, that what the amsolar tech was saying regarding the output of their panel.  That exceeds my predicted needs, even in cool weather.

Mike's point about portability of the panel(s) is key.  That is why I will not mount mine to the roof of my PUP.  I also want to do what JimS did, and bring appropriate cabling and connectors to set up my camper in the shade, and set up my panels in a sunny spot.  Also, for a pup, when the roof is down panels mounted to the roof are readily accessible, and readily stolen.

[wavery]

Mike and Wayne both added some useful points (for those still reading yet another solar thread).  

Wayne, that what the amsolar tech was saying regarding the output of their panel.  That exceeds my predicted needs, even in cool weather.

Mike's point about portability of the panel(s) is key.  That is why I will not mount mine to the roof of my PUP.  I also want to do what JimS did, and bring appropriate cabling and connectors to set up my camper in the shade, and set up my panels in a sunny spot.  Also, for a pup, when the roof is down panels mounted to the roof are readily accessible, and readily stolen.

The problem with "Expected needs" is that, that is an ever changing equation. I think that if you find that a certain "number" meets your minimum expectations, you may find yourself wanting for more. Also, if it meets your expectations on a bright sunny day, it will most certainly fall far short on a partly sunny day.

I lived with solar panels for 10 years on my sailboat (I lived aboard). I ended up with 4, 48w panels and a very powerful wind generator. Of course my needs were a lot higher than a PU but the point is, I am very familiar with what solar panels can and can't do.