Current limiter on a battery charger

[johndale]

Hi guys, I have a battery charger (manual multi stage) that I can dial up 16vdc on a 12 volt battery. Obviously the current runs from 15 ~ 25 amps depending on the state of charge. I wish to use the charger at 15 ~ 16 vdc but a max current of 4 amps for equalising purposes. What can I add to the circuit to limit the current. Thanks.

 

[hsvgtsr1]

you can use a curreny limiting circuit using current limiting transistor

 

[sabahat]

hi guys i have 4.8v NI-MH battery.iwant to charge it how much voltage should i apply to its terminal to charge it completely through 10 ohm resistor

 

[Noggin]

hi guys i have 4.8v NI-MH battery.iwant to charge it how much voltage should i apply to its terminal to charge it completely through 10 ohm resistor

You need to use constant current to charge ni-mh batteries, not constant voltage. What is the mAh capacity of the batteries? Take that value, divide it by 10 hours, and use about that much current for up to 14 hours when nearly completely drained to charge it fully.

 

[sabahat]

thank u for reply i am limiting the current at 200ma with a resistance 10ohm and i am using a 9v supply after one hour voltage on the terminal of the battery goes up to 6.2 volt and current drops to 100ma how much voltage can i lift or can igo on the terminal of bttery so the battery ll not damage the capacity of my battary is 2400ma-H.
waiting for ur reply
sabahat

 

[Noggin]

You can either stick what that resistor and charge for something like 24 hours or you can use a constant current supply such as an LM317. The datasheet describes how to use it as a current supply.