Solar panel question: 1 large or several small?

[Jim K in PA]

There is a discussion on the Viking message group about solar recharging.  It got me thinking about panel orientation and efficiencies.  A couple of folks have purchased several smaller panels and pigy-backed them together.  At first I thought this an inefficient method, but then it occurred to me that you could place the panels in an orientation that would optimize them for the changing sun angle/orientation.  A four panel system would have one aimed more toward the AM incidence, two optimized for mid-day, and one optimized for late day incidence.

HF sells 20 W panels that could be useful for such a setup.  

OK - tell me how stupid this idea is.  I can take it.  :p

[wavery]

There is a discussion on the Viking message group about solar recharging.  It got me thinking about panel orientation and efficiencies.  A couple of folks have purchased several smaller panels and pigy-backed them together.  At first I thought this an inefficient method, but then it occurred to me that you could place the panels in an orientation that would optimize them for the changing sun angle/orientation.  A four panel system would have one aimed more toward the AM incidence, two optimized for mid-day, and one optimized for late day incidence.

HF sells 20 W panels that could be useful for such a setup.  

OK - tell me how stupid this idea is.  I can take it.  :p

It would be a pain in the butt IMO.

If you have 1 panel, you can move it a couple times a day and be done with it. It will be much more effective than having 2 panels constantly pointing the wrong direction. If you do that, I will bet that you will be tweaking all 4 panels most of the time. Better to just have 1 to mess with IMO.

[bblake]

It would be a pain in the butt IMO.

If you have 1 panel, you can move it a couple times a day and be done with it. It will be much more effective than having 2 panels constantly pointing the wrong direction. If you do that, I will bet that you will be tweaking all 4 panels most of the time. Better to just have 1 to mess with IMO.

Agree with Wayne, go with one and just have it facing South.  With 4 you have four times the storage and 4 times the cables to connect.  I have a single large panel that I setup on a small wooden table at the campground.  Just face it in a generally south direction and leave it alone, works great.

Good luck.

[JimS]

For a multiple panel system, you would want all the panels to work together, meaning all would have to point in the same direction.  Otherwise, it would be inefficient for the cost of the system, as some of the panels would not be producing at their peak capacity.
Also, you would have to isolate the panels from each other.  One or two 20 watt panels in direct sunlight would need many hours to recharge the battery.  Four 20 watt panels all working together would need much less time to recharge.
One thing I notice about my system is when the panel is not in direct sunlight or is partially shaded, the output drops from 7.5 or so amps to less than 1.  I have one panel and have found that if I point it in the general direction of the sun, (mostly south and elevated to about 45 degrees) I can go about my business and as long as there is about four hours of clear skys, the batteries are fully charged from 70%.  In that amount of time, I get enough 'direct' light to do the job.
Also, check out the price of four 20 watt panels as opposed to one 80 watt.  I have not checked the prices since I put together my system so I don't know what that would be.

Edit: I checked the prices of some panels and found that four HF 20 watt panel would cost about $760.  One Alps Tech AP 85 panel costs about $515 and a Kyocera KC-85 is around $435.  My Kyocera KC-130 is around $625.

[ForestCreature]

we have 3 - 15 watt panels, and have had for several years. They work well for our need, we don't use a huge amount of power.

Here is what we did


for the rest of the pics go here
http://www.flickr.com/photos/marcy_l/sets/72157605558636408/

[JimS]

we have 3 - 15 watt panels, and have had for several years. They work well for our need, we don't use a huge amount of power.

Here is what we did


for the rest of the pics go here
http://www.flickr.com/photos/marcy_l/sets/72157605558636408/

I like this multipanel setup.  Easy to take out, put up, off the ground, pointing in the same direction, take down and store, and it does the job.

[dthurk]

We have 2 panels, 80 watts each on top of our Travel Trailer.  I have them on a tilt mount on the roof, but have always left them flat.  We've dry camped for as much as 7 consecutive nights in the Northeast and have been able to maintain power at all times.  This has all been summertime camping so we've not tried to run the furnace while dry camping.  I'd suspect we wouldn't be able to do that for long.  But summertime, we've been able to fully use the camper and recharge during the day from the panels.  We do practice resource conservation while dry camping, but remain comfortable in our rig.

[wavery]

We have 2 panels, 80 watts each on top of our Travel Trailer.  I have them on a tilt mount on the roof, but have always left them flat.  We've dry camped for as much as 7 consecutive nights in the Northeast and have been able to maintain power at all times.  This has all been summertime camping so we've not tried to run the furnace while dry camping.  I'd suspect we wouldn't be able to do that for long.  But summertime, we've been able to fully use the camper and recharge during the day from the panels.  We do practice resource conservation while dry camping, but remain comfortable in our rig.

That is probably the most realistic and sensible solar panel review that I've seen on here.

 

[dthurk]

That is probably the most realistic and sensible solar panel review that I've seen on here.
 
 

Thanks, Wavery.  We try to be sensible people.  I suppose I should add that we use 2 6 volt batteries in series to power the camper.  We've got over 200 amps of power available.  Of course, we don't want to discharge the batteries more than 50%, so we've got only about 100 amps available.  We also have a fairly expensive controller to run it all, and bought a good wiring kit to put it all together.  It's not cheap, but I love it.  It works all the time there's light, it's silent, no gas and oil to mess with and there is absolutely no set up involved.  

I know, Wavery, we've mildly clashed a couple of times on the finer points, such as 6 volt vs. 12 volt batteries and controller vs. no controller, but in the end, a solar system will work either way.  Sometimes it gets down to splitting hairs.

chas60 knows a lot more about solar than I do.  Actually, we bought our panels from him.  Where's he been?

[tlhdoc]

chas60 knows a lot more about solar than I do.  Actually, we bought our panels from him.  Where's he been?

Dave he has been in Maine;) .  I may be camping with him at Blackwoods Campground at Acadia NP this July.  We haven't camped with him in a few years.  I am looking forward to seeing him again.

[dthurk]

Dave he has been in Maine;) .  I may be camping with him at Blackwoods Campground at Acadia NP this July.  We haven't camped with him in a few years.  I am looking forward to seeing him again.

Has he been posting on the board recently?  He'd be a great one to chime in on this thread.

[tlhdoc]

Has he been posting on the board recently?  He'd be a great one to chime in on this thread.

I haven't seen him post recently, but I did get an email from him in February.

[paxsman]

I have 2 50-watt panels mainly because I bought them at price I just could not refuse(Go Craigs List).  If I had my choice I would go with 1 130 watt panel and be done with it.  I do use a charge controller because I just don