After 3+ years, got the "low key battery" warning

To open the fobs, take the key out and the halves pull apart with fingers in the key gap. Extremely easy and tool free.
I’m picking up some new batts today at Target, name brand at very reasonable cost, $1.25 each.

 

It’s a good idea to open the fob once a year and blow the dust out

 

I only implied you don’t know enough unless it’s an authorized retailer. I’ll stay with that. Which you don’t hear. You ignore the question where do they get the batteries on ebay so cheap. Doesn’t matter, it ends being a discussion at that point. Buy them anywhere you want.
I got from this to remember to replace my fob and garage remote batteries and keep one in the car. And get them from a source that gets them from the manufacturer. I come here to learn things, and also learned it is an addiction to come here.
You may have gotten from this you don’t need a screwdriver to open the case, which like you, I didn’t know either until last night. I did use a small screwdriver in the provided slot to pop out the battery. I had it upside down and the plastic pad fell out and went invisible for a while. It only goes together one way, easy to put together.
The Energizers I got at Target are made in Indonesia. Four battery package $4.99 - 15% off today.

 

i bought some cheap eyedrops on ebay, and then thought, 'what am i doing?'

 

When my first battery died, I purchased rechargeable LIR2032 3.6V batteries from Amazon. I probably won't do that again. I feel like I have to recharge them almost every month. It probably isn't good for the key fob's longevity that I am using a battery with a slightly different voltage and am opening and closing the key fob so often. I guess I will save the rechargeable ones for the Tiles I place on my key chain and in the car. I don't care if their longevity is affected because I want to replace them with airtags eventually.

 

It seems Indonesia is becoming the hub for coin batteries. I would guess they have their own company factories because most claim proprietary this and that. I really don’t think they buy same and have brand put on. Maxell may be made in Japan. Murata is a good electronic ceramic company and bought the Sony coin battery business. Toshiba should be good. Renata, Varta, I finally burned out looking at batteries online.

 

It's what has been keeping computer clocks set for years.