At the time I bought my 12V chargers, the solar models were definitely not "weed burners". The newer models apparently have that capacity in the higher end models. Then it gets to be economics. Is it cheaper to buy two whole new solar fence units, (~$300), or two small deep cycle units for my current fencers.
Further details:
My HF panel supposedly produces 5 watts, but I have never seen it. It will make 3+ watts. It's this one:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=41144
It will easily run the fencer directly with no battery in the loop.
On 2-3 clear days, the panel will add some charge to the golf cart batteries. In the summer, I'm fine. The panel keeps up no problem. In the winter, we often go 1-2 weeks with no significant direct sun. I'm in Michigan, so we have temperatures to deal with in the 0F to 32F range for November through March.
Electric fencing vs deer:
Yes, deer can jump an 8' fence effortlessly. But usually, they don't. If you train them, a 6' fence is very effective. To train them, you set up your fence, tie rags to it about every 10', and dip the rags in some fruity concoction every week for a month. I put an apple in a blender and whizzed it up with water and used that as my attractant. The deer know what apples are and recognize the smell. They sniff the rag, get the snot shocked out of their tender noses and usually give the fence a wide berth after that.
The deer are pretty short on browse material and mast right now, so they are definitely hungry. I can tell from the tracks in my field, they walk around the fenced orchard every night, but don't go inside.
It's not that they can't, they just choose not to.
If that doesn't work, you can add a two foot bar to the top of the 6' steel post, leaning out at 45* and one more wire on top. That will often spook them enough they won't try it.
Don't get me wrong, I like venison backstrap, venison jerky, venison/pig sausage, and have plenty of firepower to harvest several every fall. But I can't kill them all, and they will decimate young fruit trees if given half a chance.
What battery chemistry are we talking about with sub-c cells?
Thanks for the info so far.
troy