building charger for nokia 8110

[AL_GATEL]

Nokia 8110, 8310 can share similar battery charger, and this old mobile phone is still abundant in where I live. There is no problem to get new battery but finding the charger is pely pely difficult.

Perhaps some smart engineer here can help design a charger for NOKIA 8110 family with standard sized component.

I have some question, does this kind of charger only to supply plain DC voltage or it is has some sort of secret pulse coding.

_AL_

 

[Audioguru]

The charging circuit for the 7.4V Li-Ion battery is in the phone. It simply needs a power supply that can supply 8.4VDC to 9VDC with the correct polarity. Nobody knows how much current.
Many stores sell a "compatable" 7.2V Ni-MH battery that is completely different but it will charge and it will work.

 

[AL_GATEL]

It simply needs a power supply that can supply 8.4VDC to 9VDC with the correct polarity.

Actualy 8110 and 8310 recharge their battery really well when using big power supply, the one repair shop usually have. I would try to use LM317, to produce 9V.

I'm a bit puzzled about the charger for NiMH battery, since the charger here is labeled to work for such and such type.

 

[Audioguru]

Two lithium rechargeable battery cells are from Nokia and they are fully charged when they have a total of 8.4V and their charging current has dropped low.
Six Ni-MH cells are also 8.4V when fully charged. Some stores sell a Ni-MH "compatable" battery because it is cheaper than a lithium battery. But the Ni-MH battery has much less capacity.