It is stating that the battery voltage for one of your engines or both engines is low below 13.5 volts. Assuming gas engines or below 24volts for diesel engines.
I have to ad something I learned the hard (costly) way. A later 24v Smart Crap set-up. In the top display corner is a DCv value. It was always correct for a 24V system. This displays the out level of the DCv to DCv converter back in the engine room. NOT what the alternator is putting out or real battery levels. In this night mare, the Cummins tech did not install the strap to the new alternator voltage regulator causing over charging. The batteries were frying, the battery management relays were burning up, but that DCv value in the display stated all was correct. So, depending on your Smart Crap install, what values are you reading? Anybody got a DVM on the batteries? I could guess, if you have a DCv to DCv converter for the later Smart Crap displays, you think your battery levels are good and you don't think you have a battery or charging problem.
