Solar?????

[kirkman]

I do a lot of boon docking and camping in state forests in the shade. Is it worth my time installing a solar panel on my roof? Will it still make some electricity in the shade? And if so how big a panel should I get? I need it to keep me going for 3 to 4 weeks. I want to mount it to the roof so while I am at work it does not grow legs and walk off!
Thanks!
Jason

[mikeschn]

Bruce (bdosborn) is the person to talk to. He's posted a lot of good information on Solar.

Start here: viewtopic.php?t=12276
(Steve's index... do a search for Solar Power, it's the second match)

i.e.
Solar Power

FAQ:Solar Panel without the Technical Stuff Bruce (bdosborn)
http://tnttt.com/viewtopic.php?t=11275

etc...

[Shadow Catcher]

There are a number of factors in this equation and the first is conservation i.e. using LED lights. Shade tolerance is the big if. I in ignorance went with a high voltage panel bought used intended to be used in a grid tie system that puts out better than 50V which required an MPPT controller. But this also means it will put out useful voltage even when partially shaded but the bottom line is solar panel + shade = very little usable electricity. Bruce and I both have panels we can put out in the sun when needed and fairly consistent loads in the form of a Waeco refrigerator lights etc. I do not yet have the experience but will in a couple of months. Remember you can recharge your battery using a set of jumper cables and idling the TV.

[kirkman]

Thanks guys! I am already all LED and have the ability to hook up to my TV to charge my battery but at the end of a long day working that is the last thing I want to do, I would just rather crawl in and relax. I was hoping for a simpler method of keeping my battery charged. Thanks

[Shadow Catcher]

It can be done! I am trying out my system now with the refrigerator inside the and plugged into the 12V system. the tear is in full shade and the solar is keeping up with demand nicely. If you have no load during the day solar should do enough.

[H.A.]

mgl

[kirkman]

Thanks guys I knew I could count on ya! I am getting smarter buy the minute. No mater what my wife says!

[Shadow Catcher]

Ignorance is curable, stupidity goes all the way to the bone. Being willing to ask questions is a really good sign you are not stupid
http://www.wind-sun.com/ForumVB/index.php Is one good source and the ultimate word on RV solar is http://handybobsolar.wordpress.com Bob is shall we say a bit more than opinionated but He is right so he can be.

Today's experiment, the refrigerator started out hot and cooled to temp (about 34F) and held it all day. About 2/3 of the day the panel is in full shade. I just came home and the battery is at 100% with the outside temps at 92F.

[bdosborn]

I do a lot of boon docking and camping in state forests in the shade. Is it worth my time installing a solar panel on my roof? Will it still make some electricity in the shade? And if so how big a panel should I get? I need it to keep me going for 3 to 4 weeks. I want to mount it to the roof so while I am at work it does not grow legs and walk off!

We just got back from boon-docking for a couple of days. We used 25 amp-hrs a night running lights, the fridge, movies and the furnace. We used the 80 watt portable panel as we were camped in the shade. We were charged back up by 1:00 each day. I'm convinced that an 80 watt panel is the maximum size you'd ever need for a teardrop. A 40 or 60 watt would probably work fine for you (I'm an energy hog). You should post a list of the things you want to run and we can help you pick a battery and panel size.

Bruce

P.S. The portable panel is the one we use the most as we always seem to camp in the shade.



You can make your own folding panel pretty easily and a lot cheaper than buying an already made one.

DIY Folding Panel

[Lgboro]

Just got an 80 watt panel installed yesterday so I haven't had a chance to test to see what it will power. Mounted on the roof permanently - figured I could add another remote panel later if needed. If the rain around breaks I'll try to post pics.

[kirkman]

Lets see I will be charging 2 cell phones, a kindle fire, watching TV on a 15 inch 110volt TV run off of a 200 what inverter with a powered antenna, and running a fantastic fan.

[Shadow Catcher]

Do you have an idea of what the actual power consumption of each item is? The biggies are the inverter and TV. I know my 21" flat screen TV pulls 24W AC, the Kindle draws 1.7W while on and run time is about 7 to 19 hrs depending on screen brightness. Fantastic Fan 2 to 3 amps (the reason I went to computer case fans).
best bet is to actually monitor the amps and something as simple as the Harbor Freight amp meter that plugs in place of an automotive fuse works great.

[bdosborn]

best bet is to actually monitor the amps and something as simple as the Harbor Freight amp meter that plugs in place of an automotive fuse works great.

No need, we can estimate well enough to make some informed choices. Here's my conservative guess on what I would expect for energy usage.

Device - Amp-hrs/night
TV - 6
Lights - 2
Fan - 14.4
Total = 22.4

Charge the cell phones during the day off the solar panels and then you don't need to use the battery to charge them, its probably only an amp-hr or two anyways. I based the fan usage on my endless breeze fan that uses 1.8 amps on low for 8 hours. A group 24 battery is around 100 amp-hrs capacity so it would carry through for a night without going past the recommended 50% usage. An 80 watt panel is around 5 amps output at full load. You can figure on 5 hours a day of full output so it should keep up, but just barely. I can get 25 amp-hrs on our 80 watt portable panel by tracking the sun (moving the panel during the say so its always perpendicular to the sun). The fan is the big drain, run it for an hour or two instead of all night and a 60 watt panel would work. An 80 watt laying flat would probably work with the reduced fan usage as well.

Bruce

[kirkman]

Bruce....... So if I get a 80w panel and it's in the shade it should keep up with my use? It is kind of hard not to run the fan all night when its 88 out side. Would i be better off with 90w or 100w? Help!!!!!

[bdosborn]

Bruce....... So if I get a 80w panel and it's in the shade it should keep up with my use? It is kind of hard not to run the fan all night when its 88 out side. Would i be better off with 90w or 100w? Help!!!!!

The panel wont work at all if there's even a little bit of shade on it, no matter how large it is. The larger panel is a sure bet if you want to make sure you can keep up with running the fan all night. A 100 watt laying flat will probably keep up without a hitch, but not if there's any shade on it.

Bruce