I looked at this problem a while ago and whilst there are pumps on the market that will pump water with a solar panel, the head ( height to which you can pump ) is not too impressive.

I assume that your well is quite a way down and so you may struggle. But, if you do use an IBC container, it may be possible to run a capiliary pipe of small diameter which will constantly trickle into the butt. Link a couple and have the final overflow returning to the well. The cost can be a bit though. Don't expect any change from about £150 to get the basic set.

I hope that this helps a little.
Darren