No Electric Available!

[crisrole]

Hi`s to all...

sometimes I`ve been on places with out electricity... so I search the internet for schematic diagrams of phone chargers powered only by 9 or 12 volts but its hard for me to find.....i dont like the one available in the market because I know maybe theres more better specially when I met this site...can anyone give me a circuit diagram or link for this purpose...

thank you very much in advance.....

 

[alec_t]

If you don't have mains electricity what are you proposing to use for your 9V (or 12V) supply ? A 9V PP3 battery would be useless for this, except perhaps for the occasional emergency boost.

 

[Wilksey]

You can use 12v Leisure batteries, such out of a truck or car etc, and use a LM7805 or equivalent to get your 5v logic, or a 3.3v reg if required.

 

[RCinFLA]

Use one of the abundant and cheap cigarette lighter chargers with USB jack. Just about all phones these days use 5v at between 300 mA to 800 mA. The smartphones using the larger current.

The cigarette lighter chargers use a buck switcher power converter to take the 9v to 15v input down to 5 vdc with about 85% conversion efficiency. Don't use a linear regulator as it will generate too much heat.

Getting one with a USB jack allows you to use various devices that charge from USB ports. Some phones require resistors from USB data lines to ground to enable full current charging. Otherwise they limit their average charging current draw to less then 100 mA. Many require D+ and D- to be tied together. Most generic USB cigarette lighter chargers have D+ and D- tied together.

If you want to ensure you get the maximum chargng current then buy a cigarette lighter charger that states it charges your specific phone. It will have the correct USB data line configuration connections to tell your phone to go to full charging current.

 

[AtomSoft]

Sounds more like you should look into solar panels. If i was you i would invest in these. They are not as cheap as the other solutions but its free electricity!

 

[crisrole]

thanks guys, i get an idea.

 

[crisrole]

yes I agree with you..I dont like linear regulators too. thnks RCinFLA..