Batteries go dead overnight- Radios and remotes.

If your batteries go dead overnight, in a radio or remote,
 Check the electrolytic across the battery. It will be leaky/ shorted.
 It is a pretty common problem.
 This holds true for any battery powered device. If you put a new battery & it's dead in a few hours.
 It is easy to check for this. 
Use an ammeter (Or sub in a metered power supply)  in series with the battery lead. If the device is off, and you have draw, it is most likely the 'lytic is bad.