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Cellphone Lithium Ion Battery

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firestorm

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lithium ion current source

Today, it is easy to buy lithium ion battery which is used by cellphone. I wonder if any one has used this cellphone battery for their microcontroller project. I mean is there any special circuit to re-charge this battery? As far as I know there are more than two pins at this battery. The positive and negative terminals (pins) have label, but the other one do not have any label. I think it is used as communication channel between the battery and the charger. Does anyone know where to find any reference about the communication protocols as well as the electrical characteristic for this other pin?
 

positive and negative 3.6v battery

u should note that
--any battery need a special charger ,if u use a wrong designed charger u may damage it or decrease it's life time.
(all the batteries have a charging curve u should to apply it when u charge the battery)

--the other pin is not important pin
(i think it is usualy gnd)
 


to maximally charge a lithium battery

u know that the good charger should discharge first the battery
if u charge a charged battery this decrese its life time
 

the 3 pin is normal is diode inverted toghter with battery to monitor temperature, the accord temperature increse the diode start conduct to charge decrese corrent to inside battery to avaoid demage
 

Can I charge a NiMH battery by just using +ve and -ve terminals, and ignoring the other two pin. What precautions should I take? I'm asking this because it appears that cell charging unit inside my cell phone is out of order and I want to get assured of it my charging the battery externally.

Thanks
 

1 battery cell:
Nominal value... 1.2V
Minimal value ... 1.1V
Maximal value ... 1.4V

3 battery cells: (most mobile accu's)
Nominal value... 3.6V
Minimal value ... 3.3V
Maximal value ... 4.2V


Voltage < 1.1V ===> CHARGING:

You must have current source. For ex. 600mA;

1) Voltage on battery cell measuring
2) Voltage > 1.4V ===> END of charging
3) Voltage <= 1.4V ... next charging
4) switch on current source (for 1min)
5) switch off current source (for 1sec)
... goto STEP 1)

1800mAh batery ... approximate 3 hrs charging; max 4hrs
When charging time < 1hrs ===> battery wrong (low capacity)
 

How about battery in notebook which sometime called smart battery. I think there should be charger circuit in that battery. The notebook mainboard only need to supply the current and monitor the status through some pins. Does anyone know the communication protocol of those pins?
 

sento said:
1 battery cell:

Voltage < 1.1V ===> CHARGING:

You must have current source. For ex. 600mA;

1) Voltage on battery cell measuring
2) Voltage > 1.4V ===> END of charging
3) Voltage <= 1.4V ... next charging
4) switch on current source (for 1min)
5) switch off current source (for 1sec)
... goto STEP 1)

1800mAh batery ... approximate 3 hrs charging; max 4hrs
When charging time < 1hrs ===> battery wrong (low capacity)
Click to expand...

Could you please tell me How can i measeure the voltage in battary?
and how the sheapest charger in the market make it and it doesn't have any ucontroler to measure it???
 

Voltage measuring ... through analog input on microproc;
;;;
sheapest charger in the market.... they don't measure voltage;
You must monitor alone CHARGING TIME;
;;;
some bateries in notebooks have chip/processor/memory in the bateries;
and communication (for ex.) is through 1 wire-bus (DALLAS-communications-protocol)...
 

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