Portable Solar power

[HuckinFappy]

We're looking at building our own "Portable" Solar system for camping (in the way we define "portable", meaning "It fits in the trailer"  ).  The idea of building it from the ground up myself appeals to me, as opposed to buying a prebuilt one...seems there's significant economy in building your own panels

For those of you already bringing Solar systems, what size would you recommend (power-wise).  My rough calculations tell me that a 125 Watt system is going to charge a 50 amp hour marine battery in 4-5 hours, and that seems adequate if all we want is to charge phones/laptops/cameras, run a few LEDs at night, and maybe grind some coffee 

It also seems to me that I could provide a 125 watt system with two 2'x4' panels....

Any thoughts on this?  Am I way off the mark?  Any cautions/lessons/ideas you want to share?

[Hippie]

100 watts of solar should be perfectly adequate for your camp. We use about that at Run a Muck, along with a 100 amp hours of battery, a small charge controller and 300 watt inverter. We grind coffee, charge phones, and run all of the LED lighting we need. Just need to watch the overnight consumption and remember to turn off the inverter before going to bed 

[HuckinFappy]

100 watts of solar should be perfectly adequate for your camp. We use about that at Run a Muck, along with a 100 amp hours of battery, a small charge controller and 300 watt inverter. We grind coffee, charge phones, and run all of the LED lighting we need. Just need to watch the overnight consumption and remember to turn off the inverter before going to bed 

Thanks Jerry, somehow I knew I'd hear form ou (well, I hoped I would!).  Am I pretty close on the rest of my data?  If your 100 amp hours are drained, how long does it take for your 100 watt system to charge them? 

[Hippie]

I try to not drain the system ever, it's hard on the batteries. The real key here is to never let those batteries get below about 12.4 volts. It simply takes a bit of monitoring. That good summer high mt sun will fully charge those batteries in less than a day.

[HuckinFappy]

Excellent...one last question for now....inverter....what do you need for a coffee grinder, 300 Watt?  Or can you make do with 150 watt?

[Kenny and DeAnne]

We have a 120 watt panel on our trailer. Works well even though we get a little shade during the day. One suggestion is to use 2-6 volt golf cart batteries wired together to make one big 12 volt, they have more storage and can be drawn down farther than 12 volt marine batteries. We have a 1500 watt inverter but never use it, if i need 110 volts for something small we have a small power inverter that we just plug into a cig lighter recepticle in the trailer. Have fun building yours.

[yonderphreak]

OK, i have wanted to do this for awhile. can someone lend some advise on how and where to get started?

[HuckinFappy]

OK, i have wanted to do this for awhile. can someone lend some advise on how and where to get started?

Well I've been hunting around some, and I found this to be an interesting article.  That sort of got me started on thinking about buying cells on EBay and builing my own panel. 

Here's one auction with enough cells for a 125 watt system. 

I know folks here with experience will have more good advice, but that's sort of where I jumped off

[Bevin]

I've used two 15-watt panels from Harbor Freight for the last few years.  These ones here:
http://www.harborfreight.com/15-watt-12-volt-solar-panel-96418.html

Combined with a charge controller and a marine battery, we've been fine all week.  But those panels only give me 30 watts total, and my spot is fairly shady.  Then I broke one last year. 

Since all we're running is LED lights, 30 watts has worked so far, but unless you have full sun all day like Hippie, you'll need more than what those 15-watt panels can provide.  I'm planning on stepping up to at least a single 80-watt panel for this summer.  Combined with two, large 77Ah SLA gel cell batteries, we should be able to run all the LED lights and phone chargers we have for the entire week. 

Building your own panel sounds like fun.  I would think that a little soldering practice could really pay off in terms of cost savings.  Make sure to use a charge controller that is sufficient for your panel.  Some are 7-amp and some are 30-amp controllers.   And battery quality matters, too.  There are marine "deep cycle" batteries available at large automotive stores, and then there's real deep cycle batteries. 

[Hippie]

Well said Bevin...

Run a Muck uses 100 watts of PV into a 10 amp charge controller which charges 100 amp hours of battery. The inverter is 300 watts, enough to run a coffee grinder or small cuisinart. This configuration meets our needs for lighting, kitchen, and stereo for the week. We ran the movie house for Bela's film two years ago from this system (we may have borrowed a larger inverter).

The biggest issue with using a solar system like this is to instill in our users the need for extreme energy conservation:
1) Use DC lights only when you need them
2) Unplug that fully charged device
3) Remember to shut off the inverter when going to bed at night

These things are easy for someone who lives an off the grid lifestyle, they become more difficult for those that live on the grid and have been partying for many hours or even days ;-)

Hats off to Huckin for his desire to "do it yourself" I would like to try that someday. But I'm kinda lazy and have to wield a soldering iron an awful lot at work....

Hope this all helps

[HuckinFappy]

Thanks Jerry, I've always been a "pee on the electric fence" kind of guy

~Jeff

[Bevin]

Hey, Huckin, if you build your own panel I want to check it out this summer and maybe pick up some pointers.  Please take pictures of your build process if you get rolling on this cool project.

[HuckinFappy]

Will do! 

[itsRick]

Here is a great website for everything do it yourself. You can even learn how to build your own panels from broken scraps! I guess it all depends on how ambitious you want to get? Instructables

[landshark]

Here is a great website for everything do it yourself. You can even learn how to build your own panels from broken scraps! I guess it all depends on how ambitious you want to get? Instructables

Makes me think of Heath Kits...anyone remember those? If they don't have one we should market one. Solar Heathkits.