Mac wrote:
... "Mac, sounds like your battery needs to be replaced. A defective battery can draw excessive current when connected to your power source and heat up." In any event, after discussing with the good folks @ Adventure Pilot, it's winging its way there for battery replacement and any other upgrades/repair that may be needed. ...
Does anyone happen to know from experience whether the battery is really useful if the airplane's electrical system quits?
My 740 has run hot when charging since it was brand new. It's possible that the battery was toast when it was new. But on the other hand, that super-bright display needs a lot of electrons.
In any case, when running on its internal battery alone, my 740's display automatically dims and has never been bright enough to read in bright sunlight. And even in the dark, battery power lasts only a few minutes. So I've never counted on the internal battery in an emergency. Instead, I rely on a software iFly running on some other device--iPhone or iPad--for electrical emergencies.
So I've been toying with the idea of simply disconnecting the battery. (My 740 is long past the warranty period.) I doubt that disconnecting the battery will cause the 740 to quit working. And if the battery isn't really, actually very useful, there seems no big need for a new one.