In the middle of my last RadMission ride the PAS level lights on my LED display suddenly started flashing and then within a minute or so I completely lost power. Rad customer support pointed me to a helpful online RadMission Communication Error Troubleshooting Guide (which might suggest that the problem is not that unusual). I resolved the problem, which was in the LED display connector which had somehow gotten unscrewed and detached. The guide, however, has as a first step a disconnect/reconnect of the battery tray connector. Since that is a more difficult connector to get at, I suggest that anyone with a similar issue first check the LED display connector, which may save you some time and effort.
I also found that removing my batter from the tray, then reinserting it to make sure it was fully engaged, solved an error code 30 problem. My tight-fitting battery cover sometimes inhibits the battery from seating properly. Also applied a little electrical grease to the terminals.
To help with battery insertion/removal I picked up on a suggestion in some user forum to apply candle wax on the track and the tray. It reduces friction without attracting any grit or other substance that a liquid would.