As most new owners, I always wondered about the life span of the key's battery (and the fear of having a dead key).
My car is a little over a year old and the car just flashed the "low key battery" warning.
I try to keep the key away from charging cell phones, but sometimes I've neglected to move the key away from the (cell phone) charger.
In any event, I thought I'd share my key's lifespan with the forum.
Thanks for sharing. I often forget to take the key fob out of my pocket since you don't have to take the key out to start the car the old fashioned way. When I'm in a hurry I grab the spare thinking I misplaced it, only to find it in my pocket later on! Hopefully I won't deplete both of them too quickly.
The key goes into sleep mode, when not in range of the car (which emits a frequency that searches for, and wakes, the key).
If the key is within three feet of a flourescent bulb or a cell phone charger (or a few other devices that emit a certain frequency), the key doesn't go to sleep and causes the battery to deplete faster than normal.
I suspect the key would still be "valid" for starting the car, I am of the belief that the key battery is only for supplying power to the key's remote control button functions. For keys that insert into the ignition and that have thief protection codes the power for the reading the protection code comes from a powered coil inside, near, the inserted key.
Remember what happens when you walk out of Home Depot not having had the clerk "blow" the NON-POWERED product thief protection device's fuse stuck to the inside of the packaging. While those are only "present", or by default, not, passive devices the totally passive (until scanned) one under my dog's skin has a very high level, complex, code.
"Batteries Not Included"
It would be pretty idiotic on someone's part to not be able to start/use a car due to the lack of enough battery charge in the "key".
I'm an expert at dealing with a dead key fob battery. After almost 2 years my battery went dead. I then proceeded to replace the battery 6 times (3 separate purchases, different brand/place each time thinking I might have got a bad batch). The battery would only last about 1 to 3 weeks after being replaced. Finally annoyed me enough to make the trip to the dealer and had the entire fob replaced under warranty, no problems since then.
There certainly is no concern over issues with being stranded just because the fob battery is dead. Opening the doors and trunk required extracting and using the metal key within the fob, which obviously is a pain doing it frequently (I'm glad I didn't go thru this in the winter when turning that little **** at the end of the key requires finger tips). Starting the car by holding the fob up to the start button worked everytime, not so much a pain since I already had to get the key out of my pocket to open the door anyway. Beyond that, some additional nuisances:
The "low battery warning" only showed up once or twice through all the batteries I went through. Now, obviously the defective fob was draining power at an unusually high rate so that might be a cause.
Having to start the car with a dead fob one thing I learned was to avoid opening the door of the car while in "ready" mode. The MFD would then complain about "key not detected" until you shutdown.
Easy to forget how super convenient this wireless key is until you have to resort to the barbaric ways of the past!
Two climate control systems, one inside and the other at the tailpipe.
2007 Camry Hybrid (in service June 2006)
2004 Sienna (in service May 2003)