http://www.altestore.com/store/Solar-Panels/Kyocera-KS10-10W-12V-So...
$29 + FREIGHT
If you leave that fencer on all time, you should be able to get buy with 10 watt panel on large battery with no charge control. summer time, should get by with a 5 watt panel if fence isn't loaded to heavy, but price difference of 10 watt panel isn't that much more.
Battery, I buy the large irrigation batteries that the local dealers often have in the spring for $40.00 or replace a older vehicle battery that is still working and use the old one on the fencer.
I have used 5 watt panels, no charge control, and fencers like the (http://www.parmakusa.com/product_details.php?PId=2 parmak 12 volt fencers and get by good in summer time. fence grounded out in winter time and then it will run battery down.
Newer fencers I am buying, I am going to 6 joule fencers. would need a 20 to 30 watt panel depending on load and where you are located. (how much cloudy days) and should have a charge control. I want my critters to have a healthy respect for my fence. I would not even consider most of the farm store solar fencers. 1 joule is the very minimum.
Solar chargers
