Switching power sources, battery charging

[kellyseye]

There's a few reasons why I wanted to stay away from a relay:

- they must be slower than transistors.
- mechanical parts mean wear.
- and I really was looking for an excuse to finally use mosfets.

I sympathise with the 'excuse' but the first two resons don't parse..... a simple capacitor will prevent the volt drop for the millisecond(s) the relay switches and relay contact reliability is usually measured in the 'millions' (or 10's of millions) of operations....... Indeed, in this particular application you'll find most manufacturers use relays too - simple and cheap.