Cummins 6.7L doesn't have glow plugs but uses a grid heater. Thats the coil like graphic on the dash display. You're supposed to wait until that coil light goes out before attempting a start. It means the grid heater has heated to temperature and is ready for engine start. So no glow plugs and the grid heater no longer drawing current is why I think the low battery warning is triggered by the chassis air system drawing current.
2013 Berkshire 390RB-60
toad - 2002 Jeep Wrangler Sport