Building a battery charger

I want to build a battery charger that shuts off when the battery is fully charged. I have a 12v, 18Ah battery that I want to be charged without me having to check if it is charged completely. I'd also like to have a bicolor LED that is red when the battery isn't fully charged and when it is, the LED is green. Could you send me a simple schematic for me to build? I am a newbie.

Thanks!!!

juan123 said:

I want to build a battery charger that shuts off when the battery is fully charged. I have a 12v, 18Ah battery that I want to be charged without me having to check if it is charged completely. I'd also like to have a bicolor LED that is red when the battery isn't fully charged and when it is, the LED is green. Could you send me a simple schematic for me to build? I am a newbie.

Thanks!!!

Click to expand...

Here is the schematic that i think what you exactly want.


R1= 1Kohms D1= 1N4001 T1= 220V/17V 4A Transformer
R2= 1.2Kohms D2= 6.8V 0.5W zener LD1= Green LED
R3= 470 ohms TR1= 4.7Kohms trimmer LD2= Red LED
R4= 470 ohms Q1= BTY79 or similar 6A SCR M1= 0-5A DC Ampere meter
R5= 10Kohms Q2= C106D SCR S1= 10A D/P On – Off Switch
C1= 10uF 25V GR1= 50V 6A Bridge Rectifier F= 5A Fuse

**broken link removed** a 3A (per section) dual charger that should do the trick for you. While this design is for a dual charger, each section is identical and independent, apart from the panel meter and the meter selector switch, though they do share a common front end. As such, it would be a simple matter to simplify it to a single charger section.

This charger is not designed to turn off; rather it is designed to supply a "holding" current once the battery charge is up to the recommended level.

This 3ax2-charger PDF file is 25 MB and if some of you have problems downloading it here it is in a smaller version:

Ante :roll:

OOPS! I don’t know what happened but you need only one of these!

Ante :roll: