Using a cellular phone battery...

[Chaos Master]

Hello there!

Can I use a cellular phone battery, as a stand-alone battery, outside of a cell
phone? If yes, what components I need?

The battery has 3 pins, which I guess to be +, - (power) and a 3rd pin I can't
discover, but I think it's a "sense" pin for the cellphone to detect the charge
level, or an "enable" function for the battery. Am I correct?
Would the pin (if a sense pin) output a voltage that could be used with a
comparator?

Thanks!!

 

[Ian Stirling]

Hello there!

Can I use a cellular phone battery, as a stand-alone battery, outside of a cell
phone? If yes, what components I need?

It depends.
Lithium-ion batteries are very tempramental, it can explode if charged
wrongly.
At least you need a dedicated charger circuit to limit the voltage to
4.1/4.2V/cell and 3/2.7 on discharge.
Why do you want to?

 

[Jacobe Hazzard]

Hello there!

Can I use a cellular phone battery, as a stand-alone
battery, outside of a cell phone? If yes, what components
I need?

The battery has 3 pins, which I guess to be +, - (power)
and a 3rd pin I can't discover, but I think it's a
"sense" pin for the cellphone to detect the charge level,
or an "enable" function for the battery. Am I correct?
Would the pin (if a sense pin) output a voltage that
could be used with a comparator?

Thanks!!

Most newer cellphones use potentialy dangerous Li Ion battery packs - which
aside from being illegal for use outside of properly licensed equipment
usually come with circuitry inside the pack to thwart your attempts to do so
(smart batteries).
I would advise that you *not* experiment with this pack unless you have the
documentation that describe the internal workings of your particular
battery.

 

[Ian Stirling]

Most newer cellphones use potentialy dangerous Li Ion battery packs - which
aside from being illegal for use outside of properly licensed equipment

Cite?
I'm aware that the makers try to discourage such, but not of any actual
legislation.

 

[Chaos Master]

Cite?
I'm aware that the makers try to discourage such, but not of any actual
legislation.

I was just curious, I don't have a need to use any cellphone batts outside of
the cellphone.

 

[Ian Stirling]

I was just curious, I don't have a need to use any cellphone batts outside of
the cellphone.

It's not impossible, just awkward, as overcharge or undercharge may cause
either explosions/melting, or the cell not working any more.
It tends to be easiest to use any of the widely available battery monitor
chips.
They can be handy for some things, due to light weight and small cost.

 

[Robert Monsen]

It depends.
Lithium-ion batteries are very tempramental, it can explode if charged
wrongly.

DON'T charge them using a non-current limited voltage source, too much
current will get them hot. You don't want them to explode...

The recommended way to charge li-ion batteries is CCCV, where you apply
constant current equal to 1/4 to 1/2 the milliamp-hour rating until the
voltage across the battery gets to the rated voltage. At that point, you
hold the voltage constant until the current drops to 1/10 of what it was
initially. (You can skip the last part, but miss about 20% of the effective
charge.) Some charge controllers will also provide an initial 'conditioning'
period, so that if the initial voltage is much lower than 80% of the rated
max, it'll charge them at 1/10 the milliamp-hour rating until them come up
to 80%.

A current limited voltage supply works pretty well, as I've found. I have
several of these that I bought from a US surplus place and they work quite
well when charged this way.

Maxim advertises chips that control this process, as does Linear and
Microchip (and possibly others.) You can also usually buy chargers for any
battery that are designed specifically to handle the particular technology.

Regards,
Bob Monsen