For future info. There is NOTHING on a Motorhome that will tell you the battery is bad while driving. All it will tell you is the charging system has failed or there is a hiccup in the charging system and have it checked.
When this happens, do you have the GENSET running? When at the shop, can they duplicate the error on the dash or there is NEVER a flashing Battery indicator? I would suspect something downstream at the COACH Battery side. Something on the Coach and dual charging system is causing the Intermittant failure. Doug