4.5V Battery charging circuit....

Has anyone got or done any battery charging circuit for 4.5V battery with LED indication?
I have one transmitter with me and I have attached few Lithium-Ion batteries totalling upto 4.5V. I also have few smps (mobile chargers) power supplies capable of 5V - 500mA. I was thinking of putting a circuit which can glow an LED when batteries are charging and switch the LED off when they are fully charged.
I don't want to involve PIC in the middle so any circuit without it would be nice.
Any help is appreciated. Thanks

Here are a few application notes from Microchip on lithium battery chargers. Lithium batteries are pretty demanding about how they are charged, so there are a lot of chips that are specifically made to handle them.

Here are three solutions:

http://www.microchip.com/stellent/id...pnote=en025788

http://www.microchip.com/stellent/id...pnote=en020535

http://www.microchip.com/stellent/id...pnote=en022150

Quote:

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I have attached few Lithium-Ion batteries totalling upto 4.5V

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I thought lithium cells were 3.7 volts each, with a charged voltage of about 4.2?

And make sure your batteries are rated for re-charging. Even then be careful. LI tend to go BANG if not treated correctly.