lead acid battery charger

Thread Starter

Kaiser Ed Bayawa

Joined Mar 19, 2015
64
I have a 1200 watts microwave transformer.
I want to build a lead acid charger. Can anyone give me a circuit on how to do it please.
Any suggestions would help.
thank you
 

Dodgydave

Joined Jun 22, 2012
9,197
Microwave transformer is no good for a charger, you need a transformer with approx 25% more voltage than the battery you want to charge, like 15vac for a 12v battery.
 

Kermit2

Joined Feb 5, 2010
4,162
If it is like most MOT's the fine wire, many many turn secondary is on the outside.
Remove it careful not to damage the primary winding.
Use some 12 or 14 Guage wire and put about 3 turns per volt or about 50 turns on.
Add or remove until your AC volt meter reads about 18 VAC (rms)
 

Thread Starter

Kaiser Ed Bayawa

Joined Mar 19, 2015
64
If it is like most MOT's the fine wire, many many turn secondary is on the outside.
Remove it careful not to damage the primary winding.
Use some 12 or 14 Guage wire and put about 3 turns per volt or about 50 turns on.
Add or remove until your AC volt meter reads about 18 VAC (rms)
Can you please give a circuit diagram after i reached the 18v?
 

Kermit2

Joined Feb 5, 2010
4,162


This is the next step. It is called AC to DC rectification. The diode arrangement is called a bridge rectifier.
Once you get this done you will be ready for a regulator.
 

MikeML

Joined Oct 2, 2009
5,444
This is the next step. It is called AC to DC rectification. The diode arrangement is called a bridge rectifier.
Once you get this done you will be ready for a regulator.
For Lead-Acid Battery charging, do you need a smoothing capacitor?
 

Lestraveled

Joined May 19, 2014
1,946
For Lead-Acid Battery charging, do you need a smoothing capacitor?
It depends of the method of controlling the charge. If all he wants is a resistor currenter then, No. If he wants a charger that won't over charge his batteries then, the answer is generally Yes.
 
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