Hello Tony, The MagicBattery=Yes definitely works... I can assure you of that. If you have a registered version of FSUIPC4, please try to activate the option via the Miscellaneous Tab. With MagicBattery=Yes, I can leave to Battery on for days! <LOL> Incidentally, the APU is a "virtual" function. There is no connection to the actual buss in the simulator. I hope this helps. Regards, Robert On Fri, Mar 30, 2012 at 9:03 AM, Tony <tonys_groups@xxxxxxxxxxxxxx> wrote: > Hi All**** > > ** ** > > If you’re planning on flying a 737 for IYP Air, My advice to you is > execute the pre-flight checklist at the last possible moment, to prevent > the battery from running out before you’ve had a chance to start the > engines.**** > > ** ** > > I added the line MagicBattery=Yes to FSUIPC4.INI, within the General > section, and this made no difference.**** > > ** ** > > If anyone has successfully added this switch, I’d be delighted to hear > about it.**** > > ** ** > > I would have thought that FSX would allow the APU to keep things alive > before the engines are started, but no.**** > > ** ** > > T**** > -- AOPA Member No: 06936977