I'm trying to build a basic car battery charger.
The charger will use a 14.4V, 4A SMPS to charge the battery.
The SMPS output will be directly connected to the battery terminals [other suggestions?]. The SMPS will be a flyback convertor and I have two options in its design:
- either to take feedback from the 14.4V output using opto-isolator technique.
- or to have a separate feedback winding
Consider this situation:
The battery EMF is a stiff source (right?) say at 12 Volts.
Now if I am using option 1, the SMPS controller will never be satisfied from the feedback, because the output is forced to be 12 Volts by the stiff battery EMF, whereas the SMPS controller is constantly wanting the output to be 14.4 volts.
So the duty cycle and the output current will peak. It would be an over-load situation.
So I concluded that option 2 is the way to go.
Am I right here? Or missing an ingredient?
If you have tips about design please do not hesitate to mention.
-Mike[Klaus, Tim, Petrus and others, thank you for answers to my previous posts]