Mobile batt. charging..

[mytech]

Hi all.. i have little doubt,why we unable to charge the mobile batt. using normal transformer dc output... wat special in chargers???.
Also i wanted to charge the same batt. using emergency lamp 6v batt.
How can i do this.. do i have to put little inverter or some other ways are available?? thanks.

 

[arhi]

Hi all.. i have little doubt,why we unable to charge the mobile batt. using normal transformer dc output... wat special in chargers???.
Also i wanted to charge the same batt. using emergency lamp 6v batt.
How can i do this.. do i have to put little inverter or some other ways are available?? thanks.

do a google search on "charging li-ion battery" .. you'll get bunch of documents .. in general, charging li-ion is "problematic" as if not handled properly it can catch fire, and when li-ion battery is in flames you are in trouble (high temperature that gets even higher if you try to put it out using water) ... so .. we are not unable to charge li-ion batteries (the same search will point you to at least 3 "simple chargers") only - it is not as easy as with ni-* or lead acid batteries.

btw. this is all valid if you try to charge the battery on its own, if you want to use your phone to charge the battery, you just need a steady DC supply to your phone (check the spec for the voltage) .. the phone itself has circuit that does the li-ion charging control

 

[mytech]

Thanks arhi, So its not advisable to charge improperly right..i agree.
And all i wanted to charge my mobile without the power supply.. i mean would like to charge from external battery.. if u have any idea to do this let me know.

 

[arhi]

Thanks arhi, So its not advisable to charge improperly right..i agree.
And all i wanted to charge my mobile without the power supply.. i mean would like to charge from external battery.. if u have any idea to do this let me know.

most of "mobile chargers" I saw are simple dc power sources .. (transformer + rectifier + capacitor) .. so, imho (but you should check more), you just need to measure output voltage of your charger, make a dc/dc converter to step up/down the voltage you get from your battery to match the measured voltage and attach that to you phone ...

now, I know some phone chargers have current limiting circuit and voltage regulating circuit in them (for e.g. my i-mate charger) .. but 90% of them are plain dc power sources .. I would open my phone charger and check that's the simplest way

on "how to build dc/dc converter" I believe you should search the forum as there was at least 2 discussion about that in last month