> This summer I'm going to be working on a project with a multi-drop
> network of PICs connected to a Linux box. The network cable will
> be about 75 long. Some of the devices will be out in a garden shed and
> I would like to power them off a Ni-Cad battery/Solar battery
> combination
> I'm wondering if a switcher setup would be more effecient (I'm worried
> about the Ni-Cad). Any comments, ideas, pointers (I love pointers :-} )?

Why not power the nodes over the cable?  I'd use RS-485 over two-pair
cable, and use the second pair for 12V DC power.  Saves a lot of messing about
with batteries and solar cells.

Cheers,
Eric