iFly GPS Forum

Cobra is correct.  I have a 740, and IIRC, when I first got it I tested and the battery seemed to power the 740 for about 20 minutes, hardly enough for anything but the shortest of flights.  The biggest benefit I see for the battery is if you don't have it more or less hard wired, the cigarette lighter adapter at times can lose the connection causing the unit to shut down, then has to go through the whole startup process.  It's also nice when I shut power off to refuel the plane.  I can leave the 740 running, turn the screen off, and it's ready to go with no startup when I get back in the plane.

Not having the battery (in my 700, or if the 740 isn't yet fully charged) was the biggest problem at night, as the 740 doesn't remember your brightness settings, and your nice dark cockpit is suddenly lit up with the unit at full daylight illumination. 

Brolin, do you happen to know if disconnecting the battery will cause a 740 not to work properly? (It doesn't seem likely, but a few electronic gizmos use a battery as a kind of filter or for some other unusual purpose.)

My 740's battery is always charging for the first hour or more of every flight, even if the previous flight was that same day--so it's apparently kaput. Rather than sending the 740 in for a new battery, I'll just open the box and disconnect the battery--ot remove it altogether if it looks easy enough. Unless, of course, there's a good reason not to do that.