Pickup Key Fob Remote Battery Problem

[JetsetBkk]

I've been using the same 2 remotes for my pickup for about 18 years. They both work. I keep one in the house in a cupboard and, every 6 months or so, I swap it for the one on my key chain.

 

Yesterday was a "swap remote" day, but I also decided to test the remotes - see how far from the pickup I could stand for the remotes to still work. The result was about 4 metres. That's OK.

 

I then decided to change the batteries in one of the remotes to see how much further I could stand away from the pickup.

I have some spare Panasonic CR2016 batteries so replaced the 2 inside one remote with the two new ones.

 

The remote didn't work at all.

 

So I measured the voltage of the new batteries using my DVM - they are at 3.31v and 3.29v.

The "old" batteries are at 3.05v and 3.15v.

I put the old ones back and the remote worked.

Again I put the new ones in and it didn't work.

I also noticed that the new batteries produced a much dimmer light from the remote's LED.

 

I'm now back to using the old batteries.

 

Could it be that the "new" batteries don't produce the power necessary to make the remote work, even though the DVM shows them at a higher voltage than the old ones?

I'm stumped!   ???? 

 

[Moonlover]

25 minutes ago, JetsetBkk said:

Could it be that the "new" batteries don't produce the power necessary to make the remote work,

Yes that is possible. How long have you had the batteries lying around? They do have a shelf life and if you keep them inactive for too long their power output will be reduced. The voltage will give you no indication of that. 

 

 

[JetsetBkk]

1 hour ago, Moonlover said:

Yes that is possible. How long have you had the batteries lying around? They do have a shelf life and if you keep them inactive for too long their power output will be reduced. The voltage will give you no indication of that. 

Yes, that's what I'm hoping! The "new" ones are probably the same age as the pickup - about 18 years. ????

 

I just scanned the back of the Panasonic battery pack... could be an expiry date of March 2017?  

 

I'm now wondering why I swap the remotes over every 6 months - I wonder if the salesman told me to do that!  ????

I'll buy some "fresh" batteries tomorrow and report back whether (or not) the remotes work with them.

 

[HauptmannUK]

Batteries are not fixed voltage sources. Typically the output voltage of a battery decreases as current is drawn from it - this is due to the internal resistance of a battery. A new CR2016 has an internal resistance of around 140 Ohms. This means that if you draw 1.5mA current from the battery its output voltage will fall by around 0.2V.... so a 3.0V battery gives 2.8V under load of 1.5mA

Internal resistance increases with age and discharge of the battery. I suspect your batteries are old and the internal resistance is now very high.

Buy new batteries and ensure they are genuine - there's an awful lot of fake branded batteries on markets etc.

 

Edited May 12, 2022 by HauptmannUK

[Moonlover]

9 hours ago, JetsetBkk said:

Yes, that's what I'm hoping! The "new" ones are probably the same age as the pickup - about 18 years. ????

 

I just scanned the back of the Panasonic battery pack... could be an expiry date of March 2017?  

 

I'm now wondering why I swap the remotes over every 6 months - I wonder if the salesman told me to do that!  ????

I'll buy some "fresh" batteries tomorrow and report back whether (or not) the remotes work with them.

 

I looks to me as if they were manufactured in Feb 2008, so I reckon you've already found the problem. Your original batteries have done well at 18 years! The one in my motorcycle fob is only good for 2 years. I replaced it recently it when it started flashing a 'low battery' warning.

 

Good luck, I'm sure you've aced it. ????

[Excel]

How old were the "new" batteries you replaced the old ones with as they do lose their charge over a period of time. 

[transam]

Are you sure the original fob battery is the slim CR2016, as there are 2 other slightly thicker ones, CR 2025 and 2032.

Just a thought regarding internal contacts...

[JetsetBkk]

12 hours ago, HauptmannUK said:

Batteries are not fixed voltage sources. Typically the output voltage of a battery decreases as current is drawn from it - this is due to the internal resistance of a battery. A new CR2016 has an internal resistance of around 140 Ohms. This means that if you draw 1.5mA current from the battery its output voltage will fall by around 0.2V.... so a 3.0V battery gives 2.8V under load of 1.5mA

Internal resistance increases with age and discharge of the battery. I suspect your batteries are old and the internal resistance is now very high.

Buy new batteries and ensure they are genuine - there's an awful lot of fake branded batteries on markets etc.

 

I remember having a DVM years ago that had the option to add a small load to the battery when measuring voltage so it displayed the voltage under load. That's what made me think that the old batteries weren't actually producing the power - amps - needed and that the DVM was measuring the voltage with zero load.

[JetsetBkk]

New batteries fixed it!  48 Baht from HomePro. The remote now operates from much further away.

 

The DVM displayed the voltages as 3.24 and 3.25 volts, but that doesn't mean a lot.

On the pack: Manufacture date 11/2021, expiry date 10/2026.

 

[transam]

18 hours ago, JetsetBkk said:

New batteries fixed it!  48 Baht from HomePro. The remote now operates from much further away.

 

The DVM displayed the voltages as 3.24 and 3.25 volts, but that doesn't mean a lot.

On the pack: Manufacture date 11/2021, expiry date 10/2026.

 

Mr.DIY, 10 bht...........????