Key Fob Battery Keeps Going Flat

Hi Both of my key fobs have suddenly started flattening their batteries within 2 to 3 days of putting a new battery in. I've tried different brands of battery (but all CR2032) but they keep doing it. I had assumed it was a faulty key fob so pulled out my spare and started using it, but it then went flat a few days later and did it again a few days later when I replaced the battery in it! Maybe I've got two key fobs that have both suddenly developed the same fault, but seems a strange coincidence. So I've been trying to think if something else might be making them go flat. Could there be something that the car is doing to keep them constantly turned on and emitting a signal, or something like that? Grateful for any ideas, as its driving me mad and I'm having to carry around a pack of spare batteries in the car! Cheers Greg

G'day Greg. Surely this has to be something at the car-end of things? Too coincidental that two lots of batteries would give up on you!? I sometimes get a similar problem in that the car just won't respond to the key fob when I press it, but this is always rectified when I then use the key itself to open the car. (This is not the car "going to sleep" after the five day thing.) If I close the door and lock it and then quickly decide that I've left something inside the car that I need then it sometimes won't let me back in straight away. An obvious question, I know but this isn't the car going into sleep mode in your case is it? How long are you leaving it stand for before trying to get back in? Hopefully, Richard will see this soon and make a suggestion but I'm sure it must be the car and not the fob. Adrian.

Hi Adrian. Yeah definitely not the case of it going to sleep. Its a daily driver and I probably use it 2 to 3 times a day. I'm convinced it must be something car related too. Will get it in to get checked out if no-one can come up with an obvious solution. Cheers Greg

I can't see how it could be anything to do with the car. The car alarm module is the receiver - it doesn't transmit anything to the remote. I could understand it if it was just one remote, but for both to do the same is odd. I can only think that both remotes are faulty, or both are operating when you are not pressing the button. I would try taking them to bits and cleaning the circuit boards with some contact cleaner. Also, try leaving one of them unassembled for a few days to check that the casing isn't pressing on the button. You don't wear VERY tight jeans, do you? [ ] [ ]

I've just had exactly the same problem with my two remotes. I parked up the car last Friday, with the battery on trickle charge (leaving the window slightly open and charging through the lighter socket). Neither fob would open the car but, in the end, using the key seemed to reset everything. Glad it's not just mine!

Just had the same thing today. Car has been sat for a few days, went to move it and nothing. Assumed battery was flat again so got charger out, used key to open the door, tried starting it just in case and bingo, it started, and the key fob also started working again. I'm confused! Also, what's this sleep mode? Never heard of it.

After 5 days the alarm control module goes into energy saving mode to preserve the car battery, and it shuts down the radio remote receiver. To wake it up you have to unlock the car with the key.

Even had to waste £2.50 on a key fob battery! Wonder if the warranty covers it?

It sounds as if your car alarm has got it's days, hours, and minutes all mixed up. As Richard says, five days. Yours is doing it after about five hours. Simple test - Note time you lock the car. Leave for at least 5 hours (say 6 to be on the safe side. Try using remote to unlock car. If works ignore this posting. If doesn't work, unlock with key, lock car. Leave for 4 hours, try remote. if works then the possible root of the problem is the alarm module. If doesn't work, unlock with key, lock again, leave for 3 hours. Try remote.... "A process of elimination my dear Watson." "Brilliant Holmes, brilliant." Cheers,

Just as an aside, John. You'll probably find a cut-out in the bottom section of both passenger and drivers side rubber door seals. A bit like a half circle. These are to allow you to route an cable from the outside into the car so that you can run things like chargers, etc inside the car with the door (and windows) closed. As long as you're cable isn't too thick you should be able to then put your charger on and close the door and window and leave the car completely secure. But you're probably now going to tell me that you've got a centrally heated, alarmed garage which is lined from floor to ceiling with goose feather duvets. Whereas mine is out in the cold! Hope this helps. Adrian.

Thanks for the info guys, always learning!