• My circuit circuit is below so you can understand what I'm saying.
  • I want to make a lead battery charger that can control the charging voltage and current (no discharge.) I have a circuit that measures both that works, so thats not a problem.
  • In the circuit I posted you can see that I use a two diode full wave rectifier. It is done with a center tapped transformer. This center tap goes to the negative terminal of the battery and the other two outputs of the transformer to the anode of the SCR. The cathodes of the SCR are connected together and go through a shunt resistor for measuring the current, then a fuse, and then to the positive terminal of the battery. (This is thought for lead batteries.)

My doubts:

  1. I am measuring the current while charging. Can make the code control PWM signal for the opto to maintain the current as if it was a "Constant Current Supply?" This is because I want to charge the battery in the best way possible, you know, it has a constant current charging, then a constant voltage, etc.
  2. Is there a better way to achieve what I'm looking for? Better in a more budget way, without changing the base circuit? Can I improve the circuit with little changes?


  • \$\begingroup\$ I'd like voltage&current specified. (The higher the power, the less welcome deviations from sine (and PF 1). A battery friendly SCR charger would have used many phases (3 at least) and a choke. This century I expect HF PFC&transformer.) \$\endgroup\$
    – greybeard
    Jun 6 at 15:10
  • \$\begingroup\$ @greybeard The batteries are from 6V to 24V, and the maximum charge current is 30A. I dont know the way of doing like you said with 3 phases and a choke... Preferably i will stay with this topology, i will be reading something about what you said. \$\endgroup\$ Jun 6 at 15:16
  • \$\begingroup\$ Please show the full circuit including the transformer and both battery terminals. \$\endgroup\$
    – Andy aka
    Jun 6 at 15:22
  • \$\begingroup\$ @Andyaka Posted! \$\endgroup\$ Jun 6 at 15:35
  • \$\begingroup\$ PWM signal from a microcontroller: What frequency/cycle length are you aiming for? \$\endgroup\$
    – greybeard
    Jun 6 at 16:26


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