12 volts mobile charger

[crisrole]

Hello eveyone...
My problem is that I converted an ordinary 220V mobile charger to an input of only 12 volts to charge my phone,and it really works but the problem is that it takes a couple of hours to charge. and cant full my cp..I guess, I have something to do with its frequency but how?

I also bought some cigarrette charger they called and tried but also doesnt satisfied me specially when i look the circuit designs inside... I like isolated secondary to be safe,(like an SMPS).,
Sorry for my English......
Dear friends feel free to comment....tnx

 

[alec_t]

The charge time of your phone is determined by the phone itself; not by the 220/12V adapter (unless the adapter has an extremely low output current capability).
By 'cigarette charger' I assume you mean a charger powered from a car's cigarette lighter socket? If so, the supply voltage is only 12V and is safe without the need for isolation.

 

[crisrole]

yes I agree w/ that.charge time depends on your phone.. my phone originally draws only 300 mA at 5V. I have a variable power supply and set it to the given value,my phone then was charging but after almost 5 hours I disconnect to check but why is that still not charge...I am wondering why..? do somebody explain to me this thing...thanks

 

[Nigel Goodwin]

It most probably needs MORE than 5V to charge.

Measure the voltage the original charger provides.

 

[Shyamal]

You need to know the first charger voltage is ?

 

[crisrole]

hahaha! amazing. toink

 

[crisrole]

not a good idea, nobody still dont give me the right ans.