Just out of curiosity, if a car fob button battery is 3V but when you measure it with a multimeter it reads 2.7V can that indicate a weak battery? Is there a way to test if a battery is weak? I'm trying to troubleshoot fob issues. Thanks

 

With a 2.7V open circuit voltage, the battery is pretty much gone.

This is for an Energizer 2032:

You can see that once the battery gets to 2.8V with a load, voltage drops off pretty sharply.

 

I would expect a fresh 3V coin cell battery (e.g CR2032) to measure around 3.2V using a multimeter (under no load conditions) – a value of 2.7V (under no load) would definitely suggest the battery is flat/exhausted.

 

Thank you for the replies. Yes the multimeter is reading 2.7V with the battery completely removed without any load whatsoever.

 

I'm trying to troubleshoot fob issues. Thanks

What voltage does the fob require?

 

Replace the battery. What problem are you experiencing with the FOB and what is the applcation?

 

Replace the battery. What problem are you experiencing with the FOB and what is the applcation?

That should be the first step in any troubleshooting.

Bob

 

Once upon a time I guaranteed the maintenance for a large automation installation. Our units had Li batteries of this type for memory buffering:
The Varta 2032 come NOOB with a Voc of 3.27 .. 3.29 V. Experience told me that they were useless at a voltage of 3.00 V "under load" (the memories draw 1-digit µA), meaning that the Voc in this case would be >3.0 V.
A Voc of 2.7 V is an indication that this battery should have been replaced months ago

 

Just out of curiosity, if a car fob button battery is 3V but when you measure it with a multimeter it reads 2.7V can that indicate a weak battery? Is there a way to test if a battery is weak? I'm trying to troubleshoot fob issues. Thanks

Get the datasheet for the specific battery- it will show you the battery expected life at expected current. Adjust assessment accordingly.

 

By coincidence I’ve just replaced the CR2032 battery in my car’s remote fob. The fob would work warm out of my trouser/pants pocket, but had to be close to the vehicle to work otherwise.

The removed battery measured 2.7V under no load.

 

Car fob batteries are not rechargeable. when they are exhausted then they are replaced.
Hey, sometimes I get exhausted but am not replaced (yet), so I am rechargeable.