- My model of MX-5 is: mx5 nd
- I’m based near: Coventry
- I’m looking for technical help or recommendations on: key fob battery
I am getting a low key battery warning on my 2018 RF and the handbook says to go to a dealer! Is changing the battery really so difficult ? Can anyone tell me what type it takes and how to open the unit?
main dealer battery change prices are super silly high!
try mister minute, im sure i saw that they do battery changes for car keys
Easy enough to do yourself - battery is CR2025
Mazda MX-5 Miata Smart Key Fob Battery Replacement (2016 - 2019) - YouTube
Best learning to do it yourself, the batteries don’t last 5 minutes so you will going to dealer often otherwise! I’ts not difficult the video Mister_H posted really does show you all you need to do. They will even drain if you do not use the key, my spare fob is almost often dead when I need to use it.
A pack of 4 Energizer CR2025 is £2.25 including delivery on Amazon.
Don’t be tempted to use a 2032 (3.2mm), they are thicker and will strain the keyfob and it probably wont work (speaking from experience, I had a 20 pack so thought “it will work”) It didn’t 
Change both keys, even if you don’t use both regularly, they will both run down as they are using battery for the unlocking and walk-away locking even if you don’t press any of the fob buttons.
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Thank you all for your help. I have ordered some batteries from Amazon.
I watched a YouTube video and it took me five minuets to change the batteries in both fobs … do it yourself it’s very easy 
I found my nc key fob batteries were lasting a very short time until someone on here suggested to buy good quality branded batteries.
Made a huge difference.
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Just ordered two CR1620’s on Amazon for my NC. The current Energizer have been in the fob for at least four years.
NC key fob batteries last ages, but in the ND even decent ones don’t last long.
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Never use my spare key but on advice I change the battery every 18 months.
Today the 18 months was up and to my surprise I found the old energiser 2025 was a dead duck. Had a 2007 NC for 9 years and rarely needed a change of key fob batteries.
So yes it appears that key fob batteries in my ND, spare or not, need regular replacement.
Will have to reduce 18 months to 1 year.
Don’t make the same daft mistake as me, a clear plastic disc may need peeled from the back of the replacement battery (Duracell) before inserting it into the key fob.
Agreed.
My Mazda3 fob batteries last 18 months. A pain.
Last month I thought I needed to change the battery in my NC key fob because button presses needed to be long and hard. But I found a new battery was just as bad, and the old one tested perfectly OK for volts and current.
I carefully cleaned any possible hints of tarnish off just the stand-up tangs on the fob’s circuit-board with a cotton bud wetted by some Servisol Super 10. Then I put the old battery back in the fob.
No tarnish visible before or after, but after it was like a brand new fob with a brand new battery; working from long range across a car-park with almost no button pressure. Result!
(Beware! Don’t even think about trying to clean button pads! That will ruin them.)