The shed project crawls along and I'm thinking about ventilation now.  It's only an 8'x10' shed so a whirlybird roof vent might look too big.

The interior lighting will be a pair of these solar powered motion lights.  They use replaceable AA batteries and walmart had them on closeout for $9 each, so I cleared the shelves and got four sets.  I already have one mounted on the dark side of the house with the solar panel out front and it rocks.  I figure the batteries should last long enough to put the mower away or hang the rake back up when it gets dark (not planning on spending a lot of time inside the shed).  I need to figure out the daylight sensor and how to block them so they don't turn each other off.

So that got me thinking about finding a cheap solar panel (like Harbor Freight sells) and wiring it directly to a fan to vent the shed out on hot sunny days.  Sun shining and hot- fan turns.  Cloudy and cool- fan doesn't turn.

There is a caveat that I do not want to spend much to do this; it's really not critical (WA so seldom so hot it would require any ventilation, and I will be installing vents).

My concern is for days and times of day when it's sorta sunny and the panel is sending electricity to the fan motor but not enough electricity to actually turn it.  Will that just heat up the fan and cause it to fail?

Also, what should I be looking for with regards to panel output and fan requirements?  I think a solar panel could easily turn a small pancake fan like is used in a computer, but doubt there is enough CFM with one of those to do diddly for the shed, even mounted high up near the peak.

Thoughts?

How about this?

https://www.amazon.com/Solar-Powered-Attic-Watt-W-Ventilator/dp/B00M0NI4PS/ref=sr_1_1?ie=UTF8&qid=1503162211&sr=8-1&keywords=solar+powered+exhaust+fan


Google it then post. Took 2 sec

Thanks, I saw those but was hoping for something that can vent out the side vs out the roof.  13½" square isn't going to look right on such a small roof.  The shed faces due-south so it would have to be on the front side of the shed instead of the back (where I can't see it).  I'll re-attack later looking for one that has a separate panel; then I can put the vent on the back side.

The price isn't too bad though.  

Not sure of the price or suitability for your use but the marine places used to have solar powered vents for boats and boat covers.
might be a more suitable size for your small shed

Oh well, scratch the whole idea.  I'm going to go with these roof vents instead.  I'll need three sections and with my mil discount at Lowes it came to $30 delivered to the house.