I have a Milwaukee M12/M18 charger I opened up. My ultimate goal is to convert it into a car charger using a boost converter (I don't want to use an inverter then go to a charger, just direct to charger). I'm trying to analyze the circuit to figure out the best place to inject a DC voltage, but I'm struggling. I found a rectifier, but when I test it with my meter, it measures about 120VAC on the input and 330VDC on the output. The only label I can see on it says "HY 829" (I can't find anything online about this). So, can anyone help me find where is the best place to inject a voltage and make this board work the way I want? I'm at a loss.

 

How do you want it to work?
(If the rectifier takes 110V AC and outputs 330V DC then it is a voltage doubler)

 

I want to put 12VDC in and have it function to charge my batteries. But I did just find online some compact, 100-150W 12V inverter circuits, so that might be the better option (certainly the easier one).

EDIT: What I found is high frequency square wave (20kHz). Would that be a bad idea to feed into this charger, or should it theoretically work ok?
EDIT2: For the heck of it I put 20VDC into the circuit (connected to the 120VAC input), and I got about 19.5VDC through the rectifier.

 

I see. Does it have a 110V/230V selector switch? If so, it will really need at least 300V DC. If not, I don't know why it uses a voltage doubler, I would have expected a "universal" power supply which works from 90V to 240V AC.

 

No selector switch.