Mine doesn't drain that quickly, but I use '2' for the key fob and I find mine loses it's strength pretty quickly as well. I go through batteries I feel faster than I should be. Maybe I should swap them and see if my wife notices it too haha or if it follows me.

 

The fob batteries for our '22 last about 1-2y. I would expect that the fob most frequently used with operating the car is the one that would have the most drain on the battery, but still, it should get at least 1y. We use Duracell or Energizer batteries. Are any of the fob's buttons being continually pressed with wherever the fob is being stored? For my fob, I keep it in my jeans "watch pocket" (unattached to a ring), which seems to protect it pretty well, prevents accidental button pressing, in contrast to my other car's fob, which occasionally gets an accidental button press with it being in the larger pocket along with a small additional key ring.

 

@xydadx3
If the battery is draining that fast, it sounds like some how the circuitry in the Fob is continually staying on. Yes, the Bluetooth is always transmitting some info, but it almost sounds like out of the Fobs range it is transmitting the command to release the door locks or something of that nature. Try swapping with your wife's FOB, since her is working correctly now. If the Fob works right with you for a year, than you know the Fob is at fault. However, if you go through batteries like your original Fob, it is something that you are doing. You could be carrying almost anything in your pocket that would push against the Fobs button forcing it to transmit. It could bey keys, coins, anything. Or you could be leaning against your pocket a particular way to a desk or a stand pressing the buttons. Or you could even try removing your Fob from the pocket to insure your not pressing against it at all...

 

thanks @DJVAN and @Powerflow6
I'll take a closer look at how she stores hers. I believe its in her purse. My fobs (for both vehicles) are always hung on our key rack inside the house, which is about 30ft away from the car.
1-2 years is what I've grown to expect until recently. Half a dozen or more battery changes in a year is excessive! Analyzing every habit to narrow this down should get interesting! lol

 

It's a '23 Odyssey and this is getting annoying enough to finally warrant some further attention.

I first recorded changing out the key fob battery back in Nov '24. Since then its been changed AT LEAST 4 more times, likely more. We're getting CR2032 batteries from Amazon, though I've placed multiple orders for multiple brands including name-brands lately. They've all done the same thing: the fob works fine for a day maybe 2, then the low fob battery or fob not detected message pops up on the dash. Many time's she's had to place the fob on the push button to get it to start.

Suggest as step-1, buying a name brand CR2032 battery from your name brand local store. (ie: not a dollar store) To greatly eliminate the chance of getting a counterfeit battery.

Its noteworthy a similar problem is happening in my Subaru, though just intermittently. I recorded changing my Subaru fob battery in Oct '24 and maybe once or twice since then, so its not quite as much an issue in the Subaru as the Honda.
AFAIK this is only happening with HER fob in the Honda; I don't recall having issues when I've used mine. Same thing on my Subaru - the issue appears to be isolated to MY fob; hers seems to be working fine.

I've used a voltmeter to check the batteries are 3V before installation.

Gently, using a voltmeter to check battery voltage is not valid unless the battery has a proper load. Battery voltage without a load will not give a valid voltage condition of the battery. Battery testers have built-in loads for valid voltage measurements.

I've asked my wife to save the next battery she changes to check it after use.

I plan on swapping her and my fobs to see what happens.

What else haven't I thought of?
What could be causing such a drain on the fobs?
How can I prevent the fob battery draining?

 

using a voltmeter to check battery voltage is not valid unless the battery has a proper load

Well for one thing I feel a little dumb for not considering that. I work in industrial maintenance so these are things I should know lol

Anywho I swapped the fobs without her knowing so she wouldn’t change any habits. The set I have now is what she was using. I opened it up this evening and found she’s been putting CR2025’s in it. The 2025 I pulled out tested well into the green zone on an actual battery tested but I put a new one in anyway until I get ahold of some new 2032’s. Not sure if that’s the cause but it’s worth rectifying.

 

3 days later and the fob she’s using, which has the original battery in it is still good. 3 days isn’t exactly a long life for a fob battery but it’s better than we’ve been getting.
OTOH I put a new cr2025, which is all we had on-hand, in the other fob and it won’t do anything aside from start the car when holding the fob against the on-off button. I’ll be changing that one to a 2032 battery today.

 

Are you using Duracell batteries by chance? They have a coating to discourage kids from accidentally eating them. I was having trouble with them and switched to Energizer with good results.

 

lol it’s funny you mention it.
I learned something new today when I changed batteries. I’d have to check which brand they were but I noticed some spots on the (-) side. When I rubbed them as I was changing batteries I noticed my finger tips turning blue. Apparently there’s a dye on the batteries to rat out whoever handles them. I can only assume they also taste bad but I didn’t test that….

 

I change them out once a year.

They also last about a year on my 911. I used the Duracell ones from Costco in the giant multi pack.

 

Yeah, don't try replacing the battery with sweaty hands. It looked like I lost a battle with a BIC pen by the time I finished.

 

Contra to others, I found an issue with Duracell batteries purchased at Costco - whatever coating THEY had was completely incompatible with my stuff.
We went to Energizer, Amazon brand or grocery store (Publix) brand and it's been fine.

Side note - I took a video to show my mom how to change her battery and my Ody remote exploded into like 20 pieces.