I just had a very bad experience with my r4's batteries dying in the middle of a recording. Basically, I lost the files since the r4 didn't save the data before shutting down the hard drive. This apparently has never happened before, because I've never lost a recording in the 4.5 years of running the r4.
I am going to be doing some more recording for hire in the next few weeks and my company has agreed to purchase a Uninterruptible Power Supply for the recording rig. It needs to be small and cheap, I saw some online that essentially looked like power strips which is what I would prefer rather than a tower unit. I'm not looking for hours of run time after a potential power failure, but enough to stop the deck and save my data. Honestly, less than 10 minutes of runtime would probably be fine for our purposes.
Thanks!