Battery Charger Circuit...

I want to built a Circuit of 9V Battery Charger. But it is easy to convert 9V DC from an AC Source but i have an Problem that how to control its charging and discharging like as tha battery is full it automatically stop charging the battery and likewise it also detect the low battery. i have 555 timer ic but i dont know how to use it for this purpose i am first time using this ic. And if you think i should use any other ic please do recommend it and explain the Circuit.
Thank You,
Muhammad Yasir.

i thnk ur trying to work with a SLA battery rit??? then u need to set up a trickle type battery charger.. go through the google, then u'll get many charging circuits (Both SMPS type or linear type). SMPS type is better than the other. 555 is actually a timer ic but it hs no role in a battery charger.

Thank You for your Reply. I am just trying to charge 9V Battery But i want some simple Circuit with single IC so that it is easy to understand its Working. I have tried searching google and got some circuit but much of them were complicated. If u have any simple circuit than Please let me know.

Hi myasir786, Can you tell me about your battery? What kind of battery are you trying to charge? Charging lithium ion battery is different for nickel metal hydrid (NiMH) battery, different from nickel cadmium (NiCd) battery, different from lead-acid battery.

How many cells are trying to charge? This will determine your minimum source voltage.

Do you need fast charger (1-3 hours) or slow charge (~24 hours)?

Slow charger or trickle charge is easier to implement. For NiCd or NiMH battery, you only need a current source to charge a battery at about 0.05C (5% of the capacity, i.e. 50mA for a 1000mAh battery). Sometime people just use a resistor to limit the current to 0.05C is sufficient.

For fast charge, it is more complex. You need to detect and terminate charging. People generally use monolithic IC for fast charge.

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Hi kcyang,
Thank You For Your Reply.
Actually i want to operate an 9V Amplifier with a Rechargeable battery so i havn't decided yet which Battery should i use, i have an idea of constant Power Supply of 9V but i can't switch it automatically as Battery is low and Battery is full. so if you have any schematic with automatic on and off switching than let me know and Charging Time 24 Hrs is too much and i think battery will take very less time to discharge and takes lot of time to charge, so it will be use less.