How far away from the car does the key fob have to be to prevent it from constantly communicating with the car and therefore wearing down the fob battery? I thought 75 feet away would be far enough. But today I was successful at locking and opening the doors from that distance using the fob buttons. Is it that the open/lock buttons when pressed send out a stronger signal than the low frequency communication with the car? My ground floor apartment is that distance away from my parking space. Should I set the battery saving function of the key fob every night? This is on a 2016 Prius three and I have only had it less than two weeks, so I am still learning. The manual helps sometimes but isn't very clear about some things. Thanks.
Interesting point. Why not find out how much replacement batteries cost? And you have two key fobs. Why not set the one you're not using to sleep so that it stays fresh? And then just use the other one as normal, without having to remember to set the battery saving function on it every night?
I was using "sleep" as shorthand for "battery saving", sorry. Another option is to simply remove the battery from the second key fob. Then it's really "asleep".
Battery replacement costs 7 dollars if the dealership does it. The sales person told me the day I got the car. The battery probably can be purchased for less than 5 dollars and the manual explains how to do it. I have been thinking of putting the spare key fob in the battery saving mod. Thanks for reminding me.
I don't know if the Gen 4 fobs are very different from the Gen 3, but I changed the batteries in my Gen 3 key fobs myself no problem.
You can test the distance yourself. Walk towards the car at night and find out when the interior dome lights come on. Mine come on at around 5 feet from the car. (It's a neat feature, not sure if all cars have this feature.) I promptly ignored the distance and hung both keys in the garage next to the car. The key is also on the same ring as a magnetic key ID card badge I use for work which is another no-no for fob battery life. I do this so I never forget or lose my keys or badge. My fob battery promptly ran out of juice after one year's use. Cost was $2, I think. (5 for $10 on Amazon) At this point, I didn't really care. Cost is insignificant. I rotated to the second key fob just to even out wear on both fobs. Guess what? At year 3 with the 2nd fob or 4 years total ownership, now the second fob is reporting low battery. Yeah... I really don't care now. I'm even giving away some of my extra fob batteries because I'm afraid they'll lose charge on their own before I ever need them.
The fob can transmit about 30 feet. The proximity detection works to about 3 feet. You can see when that detection occurs by watching the red LED of the fob. In addition to flashing when you press a button, it also flashes when it receives the signal from the car and replies.
