W202 Keyfob battery cr2025 or cr2032?

[whitegold]

I've been suffering a low battery-Remote Central Locking warning for a while now (that's Red+Green flashing together) on unlocking or locking.

New cr2025 batteries did not help. However, cr2032 batteries not only cured the low-batt warning, but have radically improved the keyfob range.

I notice in an answer on another thread, it has been suggested that these batteries are "the same", and 2025's can be used.

While both are 3.0v Lithium cells, the 2032 has a slightly larger capacity. Physically, the 2025 is 2.5mm and unsurprisingly the 2032 is 3.2mm thick.

Both battery types fit the fob- in fact I seem to recall bending in the tabs at some time or other to "tighten" the sloppy contact with a pair of 2025's.

I don't have EPC access, so I can't check if the MB part #s are the same all fobs.

 

[television]

The CR2025 is the correct one, but do adjust the claws so that they are tight

 

[whitegold]

Thanks for the reply, Malcolm.

It may be that "All 2025's are not equal" & I'm working with a bad batch of them. (pack of 10)

What's aroused my curiosity is the radical increase in range - I can now operate the CL from many yards away on 2032's whereas the 2025's won't even work through the rear window!

Since the 2032 has a stated capacity of approx 1400mAh as opposed to 900 for the 2025, at least I'll expect them to last a bit longer.

Regards Simon

 

[television]

I do know Simon that many of the cheap packs do not last any where near as well as say a Duracell ,,big problem is they are not dated so we have no idea how long they have been in stock ,in theory there should be no difference in the range with either. One should not try and measure the voltage off load, in the keys they only draw a few mili amps

 

[ShaunB]

Folks

Old thread revival here.

I purchased two new CR2025 batteries(duracell) for my W209 key fob.
When I opened the fob, I found it had CR2032 batteries in it.

Anyway, the CR2025's don't seem to work, car doesn't respond to buttons.
I put the 2032's back in it again and low and behold they work.

Manual did say 2025.
The 2025 batteries did appear to be loose in the holder?

 

[Mark@RMK]

Probably a loose connection with the metal parts of the battery holder!

Try bending them a little and make sure the red led flashes when you press the buttons!

 

[television]

As Mark if a 32 battery has been fitted it will force the connections apart, bending them in carefully will cure that.

 

[ShaunB]

Thank you both for replying.
Mark - I guess the answer is probably no, but do you ever do any work in N.Ireland?

 

[ShaunB]

Probably a loose connection with the metal parts of the battery holder!

Try bending them a little and make sure the red led flashes when you press the buttons!

Tell you what, if you are able to repair my spare key, then you'll be getting the working key in the post for refurbishment :lol: