battery charge

[joshelectro]

hi people
will 12V 1AMP transformer charge a 4.5AH 12V battery ?

 

[Ian Rogers]

Not really! To charge a battery current has to flow.... You need about 13.6v to charge a lead acid 12v battery..
Transformers typically output a higher voltage than specified on the unit....

If you hook it up.. put an ammeter between them and see which way the current is flowing... It definitely won't charge it fully....

 

[crutschow]

Is the "transformer" output AC or DC?

 

[joshelectro]

The 12v it is ac
center taped transformer

 

[k7elp60]

The 12v it is ac
center taped transformer

With a rectifier, filter and regulator it will charge the battery. Would you like a schematic of a charger?

 

[joshelectro]

ya please it will be helpfull

 

[MrAl]

Hi,

Just to note, if you are just charging a battery you dont actually need to filter the rectified DC. As long as the AC is rectified it will charge the battery.
But you do have to pay close attention to the current and the battery DC voltage. The current can not be allowed to go over the manufacturers recommendation.

 

[k7elp60]

I agree with Mr AL. Sometimes it is easer to use one component that does it all than use some to limit the voltage, or current or both.
The attached circuit uses a 12v charger module specifically for 12 volt lead acid batteries. The PB137 regulates the voltage very close to 13.7 and
as a result the battery will never overcharge. Mouser lists them for a little over a dollar.