How to put higher capacity battery into old Nokia Mobile Phones

Have they always gas short talk time? If they are AA batteries you can replace with rechargeable NiMH with as high milliamp hours as you can get 2400+ these have much more staying power. They should charge ok but sometimes these can upset the charge unit.

Sometime replacing of battery is right, it is more costly So you better go to mobile tech or you can do this.

Dont talk or use mobile phone when the phone is charging its battery and charge your mbbile battery for 10 hrs continusly before intinal use Only Charge your mobile when it shows " LOW BATTERY " Dont over charge your mobile Use the mobile to talk only when the network signal is high else use sms facility to communicate Use only original charger to charge the battery

i think that you might have not properly charged your batterry before first use it is being noted that all mobile manufacture recommends at least 10- 15 hrs of continus charging of the battery with the phone swtiched off is needed to work effectively in the future if you do so life of the battery will incress and you can incresse the back up of the battery and it is proven also so charge the battery well and try and remeber only recharge the battery agin when a battery low signal is shown
these are some tips :
Dont talk or use mobile phone when the phone is charging its battery,
Only Charge your mobile when it shows " LOW BATTERY ",
dont use mobile if any water particals get inside the phone ,
use only orginal battery ,
Dont over charge your mobile,
Use the mobile to talk only when the network signal is high else use sms facility to communicate,
Change the mobile battery as soon as possible if it damaged,
Use only original charger to charge the battery,
when you try to remove battery make sure that the phone off,
if the phone is not using in long time remove battery and keep it safe,
Dispose the battery safely if its life is over