I am making a handheld radio telescope which needs 13-18v to power and currently runs off 2 9V batteries. However it eats power like mad, drains them so hard that it actually needs to be recalibrated every 10 seconds. Now I am looking for a way to give it a stable power supply and more importantly to make it rechargable.
Now I was wondering if it would be possible (and smart) to take appart one of these chargers and wire it in with a swich. one position would make the device run off the batteries and the other side would charge the batteries and run the divice on power (which comes from the plugged in cord)
Alternatively, if that is a really bad idea for some reason, what about making it run on a laptop power supply? (19V but should also work) I got some BNC connectors, so I could swich the head and make it work off of that. It would not be rechargable, but atleast I could use a long cable.