adding a solar charger on to rechargeable batteries

[wjwren]

Hopefully not too complicated but this is what I want to do...

I have an alarm external bell box that takes C type batteries (4). How could I add a solar charger and rechargeable batteries to this. Is there an off the shelf kit available?

[buggalugs]

If it totals 6v there's plenty of chintzy chinese 6v solar charge controllers on ebay