Electronics boffins please help.

I have a remote key fob with a GP 12V 27A battery, press the buttons and a small LED lights up and operates the garage door.

The battery is low so I have tried to replace it, when I insert a new GP 12V 27A battery the LED lights up very brightly and the buttons won't operate the door, if I put the old battery back in, the key fob works as it should, the LED only comes on when the buttons are pressed.

I am puzzled as to why it works with the old battery but won't work with a new battery, I have tried two new batteries from two different suppliers.

The only thing I can think of is that the original battery isn't what it is claimed to be.

I have a remote key fob with a GP 12V 27A battery, press the buttons and a small LED lights up and operates the garage door.

 

The battery is low so I have tried to replace it, when I insert a new GP 12V 27A battery the LED lights up very brightly and the buttons won't operate the door, if I put the old battery back in, the key fob works as it should, the LED only comes on when the buttons are pressed.

 

I am puzzled as to why it works with the old battery but won't work with a new battery, I have tried two new batteries from two different suppliers.

 

The only thing I can think of is that the original battery isn't what it is claimed to be.

Symptoms imply that the voltage on the new battery is too high.

Do you have the make and model of the device itself?

Symptoms imply that the voltage on the new battery is too high.

Do you have the make and model of the device itself?

Thanks unbeliever

That's what the chap in Maplin thought, he looked at the old battery and sold me a new replacement battery, I had initially thought the first new battery bought off line might have been a fake. Its looking more and more like the original battery isn't what it is claimed to be, I'm starting the think the manufacturer as made it in such a way that I can only buy a new battery from them, looks like I will have to contact them.

Thanks unbeliever

That's what the chap in Maplin thought, he looked at the old battery and sold me a new replacement battery, I had initially thought the first new battery bought off line might have been a fake. Its looking more and more like the original battery isn't what it is claimed to be, I'm starting the think the manufacturer as made it in such a way that I can only buy a new battery from them, looks like I will have to contact them.

If you have the make and model, we can probably find the manual online which ought to have the battery spec.

If you have the make and model, we can probably find the manual online which ought to have the battery spec.

I found the manual on line and the batteries I bought are correct according to the manual, it does say they sell the batteries so I will have to try them, if their batteries work they must be marking them up incorrectly intentionally to get customer to return to them for new batteries. I'm guessing they will cost more than a couple of quid if that's the case.

Can you measure the voltage on the old battery with a multimeter?

Can you measure the voltage on the old battery with a multimeter?

I was going to suggest this.

But if the battery is near dead, the voltage may have dropped.

Best to measure it out of the device as the device will draw more current than the voltmeter.

Yes that's a good idea but I don't own a multimeter, maybe one of the nice peeps at Maplin will check it for me, I'll give them a try.

M&NIC is right in what he said.

A five quid multimeter is worth an investment. Like others have suggested, measure the battery voltage after taking the battery out of the device. With a lot of electronic equipment a small voltage variation can send the device "out to lunch". Good luck. You will probably have to bite the bullet and go to the manufacturer.

Why not connect the battery to a bulb in order to reduce the voltage a bit and then try it again?

Why not connect the battery to a bulb in order to reduce the voltage a bit and then try it again?

Good idea

New batteries tend to drop their voltage a bit after a small time of use and then stabilise to a constant so could well work by doing that.

Good idea

 

New batteries tend to drop their voltage a bit after a small time of use and then stabilise to a constant so could well work by doing that.

Apelike.

You are right all batteries have a "shelf life".