How can I detect if an LV line is powered?

I'd like to turn some redstone on and off, depending on whether an LV line powered by solar panels is on or off. Is there a way of doing this?

They are IndustrialCraft Solar panels, which are powering a batbox, which is in turn powering a copper cable, the status of which I'd like to query.

I am using the Direwolf FTB modpack.