I've seen inside drill batteries before (NiCad ones) and there's usually just three terminals to the pack, -ve, +ve, and one for the temperature sensor. But this one has a 4th pin, which is connected to the -ve of the batteries via a 10K resistor. What is its purpose?

https://www.dropbox.com/s/1np3y4ubr4....jpg?dl=0&s=sl

Bottom left large pin is connected to -ve of cells and one end of the temperature sensor (a little black blob) and one end of the 10K resistor.
Right large pin is connected to +ve of cells.
Top left large pin is connected to the other end of the temperature sensor.
Small pin is connected to the other end of the 10K resistor.

I don't have access to the charger for this pack, I only bought this pack to take the cells out to replace them in my own battery pack, as this one was half the price.

In article , says...

I've seen inside drill batteries before (NiCad ones) and there's usually just three terminals to the pack, -ve, +ve, and one for the temperature sensor. But this one has a 4th pin, which is connected to the -ve of the batteries via a 10K resistor. What is its purpose?

https://www.dropbox.com/s/1np3y4ubr4....jpg?dl=0&s=sl

Bottom left large pin is connected to -ve of cells and one end of the temperature sensor (a little black blob) and one end of the 10K resistor.
Right large pin is connected to +ve of cells.
Top left large pin is connected to the other end of the temperature sensor.
Small pin is connected to the other end of the 10K resistor.

I don't have access to the charger for this pack, I only bought this pack to take the cells out to replace them in my own battery pack, as this one was half the price.

myabe it's to identify the battery?

Jamie

"Mr Macaw" wrote in message news
I've seen inside drill batteries before (NiCad ones) and there's usually
just three terminals to the pack, -ve, +ve, and one for the temperature
sensor. But this one has a 4th pin, which is connected to the -ve of the
batteries via a 10K resistor. What is its purpose?

https://www.dropbox.com/s/1np3y4ubr4....jpg?dl=0&s=sl

Bottom left large pin is connected to -ve of cells and one end of the
temperature sensor (a little black blob) and one end of the 10K resistor.
Right large pin is connected to +ve of cells.
Top left large pin is connected to the other end of the temperature
sensor.
Small pin is connected to the other end of the 10K resistor.

I don't have access to the charger for this pack, I only bought this pack
to take the cells out to replace them in my own battery pack, as this one
was half the price.

If your battery pack doesn't have one - don't worry about it.

On Sun, 10 Jan 2016 22:13:27 -0000, Ian Field wrote:



"Mr Macaw" wrote in message news
I've seen inside drill batteries before (NiCad ones) and there's usually
just three terminals to the pack, -ve, +ve, and one for the temperature
sensor. But this one has a 4th pin, which is connected to the -ve of the
batteries via a 10K resistor. What is its purpose?

https://www.dropbox.com/s/1np3y4ubr4....jpg?dl=0&s=sl

Bottom left large pin is connected to -ve of cells and one end of the
temperature sensor (a little black blob) and one end of the 10K resistor.
Right large pin is connected to +ve of cells.
Top left large pin is connected to the other end of the temperature
sensor.
Small pin is connected to the other end of the 10K resistor.

I don't have access to the charger for this pack, I only bought this pack
to take the cells out to replace them in my own battery pack, as this one
was half the price.

If your battery pack doesn't have one - don't worry about it.

I know, I was just wondering what it was used for.

--
How to start a fight, number 46:
Wait till a bunch of girls walk past a phone box.
Phone the phone box.
When one answers, ask to speak to the ugliest one they've got.

"Mr Macaw" wrote in message news
On Sun, 10 Jan 2016 22:13:27 -0000, Ian Field
wrote:



"Mr Macaw" wrote in message
news
I've seen inside drill batteries before (NiCad ones) and there's usually
just three terminals to the pack, -ve, +ve, and one for the temperature
sensor. But this one has a 4th pin, which is connected to the -ve of
the
batteries via a 10K resistor. What is its purpose?

https://www.dropbox.com/s/1np3y4ubr4....jpg?dl=0&s=sl

Bottom left large pin is connected to -ve of cells and one end of the
temperature sensor (a little black blob) and one end of the 10K
resistor.
Right large pin is connected to +ve of cells.
Top left large pin is connected to the other end of the temperature
sensor.
Small pin is connected to the other end of the 10K resistor.

I don't have access to the charger for this pack, I only bought this
pack
to take the cells out to replace them in my own battery pack, as this
one
was half the price.

If your battery pack doesn't have one - don't worry about it.

I know, I was just wondering what it was used for.

Someone else suggested identification - the tool could measure that resistor
to see if its what's expected. It looks like 1% tolerance which would make
sense in that context.

If its a cheap knock-off battery, that resistor could be pretending to be a
temperature sensing thermistor at within spec temperature.

On Mon, 11 Jan 2016 20:05:02 -0000, Ian Field wrote:



"Mr Macaw" wrote in message news
On Sun, 10 Jan 2016 22:13:27 -0000, Ian Field
wrote:



"Mr Macaw" wrote in message
news I've seen inside drill batteries before (NiCad ones) and there's usually
just three terminals to the pack, -ve, +ve, and one for the temperature
sensor. But this one has a 4th pin, which is connected to the -ve of
the
batteries via a 10K resistor. What is its purpose?

https://www.dropbox.com/s/1np3y4ubr4....jpg?dl=0&s=sl

Bottom left large pin is connected to -ve of cells and one end of the
temperature sensor (a little black blob) and one end of the 10K
resistor.
Right large pin is connected to +ve of cells.
Top left large pin is connected to the other end of the temperature
sensor.
Small pin is connected to the other end of the 10K resistor.

I don't have access to the charger for this pack, I only bought this
pack
to take the cells out to replace them in my own battery pack, as this
one
was half the price.

If your battery pack doesn't have one - don't worry about it.

I know, I was just wondering what it was used for.

Someone else suggested identification - the tool

Or the charger.

could measure that resistor to see if its what's expected.

I see. Although I didn't see the someone else if it was in here.

It looks like 1% tolerance which would make sense in that context.

Yes, 10K 1%. I wondered why they used a tight tolerance one.

If its a cheap knock-off battery,

It's a "Bosch equivalent". I did test it and got precisely the capacity he advertised it as (he said 1300mAh, the casing said 1500mAh, the cells said 1300mAh, and they held 1300mAh). I've been irritated at batteries form China in the past (although this was a UK seller) that claim something like 1600mAh on an AAA NiMh that only hold about 500! Avoid Ultrafire and Trustfire.

that resistor could be pretending to be a
temperature sensing thermistor at within spec temperature.

But there is also a thermistor on different contacts.

--
President Bush is rehearsing his speech for the Beijing 2008 Olympic Games.
He begins with "Ooo! Ooo! Ooo! Ooo! Ooo!"
Immediately his speech writer rushes over to the lectern and whispers in the President's ear:
"Mr. President, those are the Olympic rings. Your speech is underneath."