Interesting thread, I was not aware of the possibility of the key fob battery draining when close to the car. I have a 3 car garage, with the door into the house near the middle car, and the keys stored a few feet from there. Two cars are about a year old, and the other is 3 1/2 years old but new to me about 7 months ago. Haven't measured, but I'd say the closest car is about 10 feet and the two outer ones are closer to 15+ feet.
All 3 can normally be unlocked by hitting a button on the car and the transponder is in my pocket. Would it be an adequate test to check the location being far enough away to avoid battery decline if the car can't be unlocked when the transponder is in the storage spot? Given the age I wouldn't expect any battery decline yet. I will need to double check, but I don't believe any of the cars can be unlocked with the remote in the storage spot. I suppose I could play with it placing the remote at different distances.
Any knowledge on how to test for this, and whether my suggested test is adequate?
Found an article that quoted 6-10 foot range as typical.
VERY informal testing on my situation... distance to front of middle car is just under 10 feet. Other cars are only a couple of feet more, less than I estimated.
None worked at normal storage location.
Moved all fobs into garage close to door at 3-4 foot height, about 5 feet closer. This would put the fob of the middle car (Audi) just 2-3 feet from the front of the car. None worked.
Put each on floor adjacent to car door, each worked.
Next I moved each fob 3-4 feet away but at height (on top of adjacent car or garbage can). Each worked.
Moved further away, perhaps 6-8 feet from door. None worked.
In playing with the distance a little, it seems to matter where the fob is relative to the door I'm trying to unlock, not just the car. One car (2021 Lexus) seemed to allow a shorter distance than the other two (2021 GMC and 2018 Audi). Fob was 2 feet from car but 4-5 feet back along the car from the door button and did not work.
I'm not sure if these means the fob is not communicating with the car at distance, but am thinking this might be a reasonable assumption. Since I seem to have a cushion of at least several feet, I'm figuring I'm safe where I'm storing them. But this is good to know so I can monitor in the future if the batteries in the fobs go low.
Sort of a related note, these 3 cars are all the first time I've owned any vehicles that didn't require a key, so my prior fobs were all transmit only. And one of the articles I found suggested these types of fobs have batteries last 3-4 years. Much shorter than I've experienced with my prior transmit only fobs.
Appreciate any insight from others experience.
