BLUF: Starting your M1-series tank’s engine is a part of regular maintenance.
There are lots of M1-series tanks sitting around the motor pool with dead batteries simply because crews don't start the engines on a regular basis.
Starting the engine is part of BEFORE PMCS, but it's a good idea to do it at a minimum of once a week if possible. A lot of battery problems could be avoided if crews would start their tank’s engine regularly.
Let the engine run for at least 30 minutes at tactical idle (set TACTICAL IDLE switch to ON). That’s important because the charging system takes 15 minutes or more to bring the battery charge level back to where it was before starting the engine.
Follow the start procedures found in TM 9-2350-264-10 (Sep 11, w/Ch 4, Jan 18) for the M1A1, TM 9-2350-388-10 (Jan 18, w/Ch 2, Oct 21) the M1A2 SEPv2 and TM 9-2350-412-10 (Apr 20, w/Ch 1, Jan 22) for the M1A2 SEPv3. That prevents damage to electrical components, reduces battery problems and increases unit readiness.