DIY or Buy
 

Just wondering your thoughts on weather one should build panels or buy. I need a 20 watt panel to run the fan in my pop can solar heater. The fan that I will be running is rated at 12 watt. Will I be OK to use this size of panel? I was also thinking of hooking panel to a battery and then to the fan. What are thoughts on this idea?

Can you build one for $60 that will give you 20 watts and be weather proof for decades?
My advice is to buy a factory made panel..

20 Watt Solar Panel | eBay


I've got 11 of them!

http://i46.photobucket.com/albums/f1...solarfarm2.jpg

Those on the tracker have been blown over and had a tree drop on them..
Still ticking! :D

Nice set up you have Xringer, I tried the link you posted and the sale is not available in Canada. Here is one that I found in Canada and it has free shipping :thumbup: Solar Panel KIT Panneau Solaire 20W 20 Watt MONO with charger cable MC4 RV | eBay

That Panel has a Charge Controller with it, and it looks like it has a load control output.

You could use this rig with an old 12v car battery, and connect your fan to the load
output of the CC. The battery would be protected from being deeply discharged.
Since the CC will disconnect the battery from the fan(load terminals) when it's voltage is too low.

It would be best to have a thermostatic switch in the solar heat output duct,
so it could turn on the motor, only when the cans were hot enough to provide some BTUhs.. :)

Without a thermostatic switch, the battery will be run down to a low point
each evening and part of the early morning sun would be wasted,
while the CC was playing catch-up..
But, it might work, you never know until you try. :D

That looks like a pretty good panel, all mine are Mono and they aren't too bad.
My Canadian Solar panels give the full 200w on any bright sunny day..

Shop around, you may be able to find the same rig for less money..
I've seen those type of Chinese CCs (Sometimes called street lamp PV controllers) for less than $20USD.


I think your 12W motor should be good with the 20W panel.. I've seen one of my 10W
panels move my heavy tracking array, while the battery was disconnected!
But that was a bright sunny day.

Just remember, your system might be picking up enough sun on an overcast day
to provide some good BTUhs. BUT, your PV might only be putting out 1 or 2 watts..
That's not going to run your motor very well. Wasting the warm air in the cans..

IMHO, the best fix for the overcast problem, is a large car battery+ a thermostatic switch to save the battery.

Thanks for the reply Xringer. That is what I was thinking of doing is connecting CC to and old 12 volt battery. I have one that came out of my wife's car , we thought that the battery was toast because one morning we went to start the car in the winter time and the battery dead. Here I found out that with the ignition switch turned off I was still getting a load on the battery. I was able to bring the battery to charge but it is on the weak side for a car, so only having a light load with the fan I should be OK to run this 12 watt fan for the winter anyways. I think I will be ordering that panel that I provided the link for. I can find them cheaper on e-bay but the shipping cost just kill us up here in Canada, especially when things are being shipped out of the USA.

Your tracking solar array is pretty neat. Did you use an old horizon to horizon Satellite dish mount? If I had more room in my back yard I would like to do something like what you have. As it goes I still have a 10 foot dish that I am still using. With an array like you have I would have no back yard left.

It's an old sat mount. Called a 'Polar' mount. It's been doing the job for a while now.
http://ecorenovator.org/forum/solar-...r-project.html

But, I kinda like the fixed array w/ angle adjustment. Super simple to get running. :)

Like I said, shop around. You might get lucky and fine one cheaper,
or maybe a 25 or 30w panel in the same price range.

IIRC, my first 10W panel was about $20 shipped. I got the other two
10w free with my four 125w panel order.
In the past, I have seen 30w panels sold pretty cheap. 40 to 50 dollars IIRC.

I change my car batteries every 6 years, so I end up with some useful batteries.
My current 'old' batteries are from a 2004 Toyota & a 1999 Honda CRV..
They both work almost like new.. Being indoors at 65-70 deg F helps too.