Regulate DC Voltage to Charge 12V Battery

[Rev_1911]

Ok, so I have a variable DC voltage source that changes as due to outside factors. The voltage ranges between 9 and 18 volts with a current between 1 and 3 amps. I want the voltage source to charge a 12 volt battery continuously until it is full. Whent he battery is full, the circuit should shut off delivering the voltage from the voltage source to ground. The input to the battery can be below 12 volts, however, I don't want the voltage to ever reach a value larger than that. Can someone please help me?

 

[jim hardy]

A search on "battery charger IC" takes you to many manufacturers' literature for modern battery charger circuits.

TI, National, LTC, Maxim all make them.

http://www.maxim-ic.com/app-notes/index.mvp/id/680

et al

 

[vk6kro]

You should be able to do that with just the power supply.

Set the current limit to 3 amps and the voltage to 13.6 volts.

The supply will then deliver 3 amps to the battery until it charges to 13.6 volts when it will stop charging.

Assuming the battery is lead-acid, the voltage when it is fully charged will be 13.6 volts.

 

[Averagesupernova]

VK6KRO is right. But to limit at to 12 volts as you originally intended the battery will never be charged.