[SOLVED] Problem on circuit board of carger

[RajivConfident]

I am working on battery having small size and high voltage.So i need a charger circuit having high frequency.Hence i want to know what component is responsible for developing higher frequency.

 

[Audioguru]

A frequency is AC. A battery is not charged from AC. Instead a battery is charged from a DC current.

You forgot to tell us what type of battery. Is it lead-acid, Ni-Cad, Ni MH or Lithium?

 

[RajivConfident]

I am using lithium in battery.Please provide me a circuit diagram of charger.

 

[Audioguru]

The charger circuit for a Lithium battery is fairly complicated. That is why most Lithium chargers use a charger IC designed for the job.

1) The charger must detect if the Lithium cell has a voltage lower than about 3.0V then reduce its charging current until the voltage reaches about 3.3V.
2) If the low charging current does not cause the cell voltage to reach 3.3V in about 15 minutes then the charger should stop trying to charge the "defective" cell.
3) If the cell voltage is 3.3V or more then the charging current must be limited to the amount recommended for the cell.
4) The charging voltage must be limited to 4.20V.
5) When the charging voltage reaches 4.20V then the charging must continue until the charging current drops to a few percent of the normal charging current then the charger must disconnect the cell.

I charged two matched 18650 Lithium cells in series many times without causing a fire by using an LM317 voltage regulator set to 8.40V and the current was limited by the 9VDC/500mA wall-wart.
I disconnected the cells after a few hours. If you are charging two or more unmatched cells in series then a "balanced" charger circuit must be used.
I use the two series 18650 cells in a portable vacuum cleaner that originally had a 7.2V Ni-Cad battery.

 

[RajivConfident]

i use the voltage of 2.5v and the battery is charged by that voltage.but when i use that battery it doesnot remains up to 4-5min.Hence i want to know that how to increase the life time of battery.Does the charging power effect the lifetime of battery?

 

[Audioguru]

i use the voltage of 2.5V and the battery is charged by that voltage.but when i use that battery it doesnot remains up to 4-5min.Hence i want to know that how to increase the life time of battery.Does the charging power effect the lifetime of battery?

You did not read or you do not understand what I told you in post #4.
A lithium battery cell is dead and is destroyed when its voltage is 3.0V or less. It might catch on fire or blow up if you try to charge it.
A lithium battery cell is usually charged when its voltage has dropped to 3.3V to 3.5V. It charges to 4.20V.

The running time for a fully charged battery depends on its mAh rating and the load current. An example is a new Li-Po battery with a rating of 2200mAh. It can supply 22mA for 100 hours, 220mA for 10 hours or 2200mA for 1 hour. It might be able to supply 22A for 5 minutes.

If it has not been discharged to below 3.3V and has not been stored fully charged then a high quality lithium battery can be charged and discharged 500 times. A cheap Chinese battery might last for 20 times.

A Lithium battery is dangerous if a proper charger is not used. The battery can catch on fire or blow up like a bomb.