How do you calculate how to charge an electrolytic capacitor? What resistor to use? Etc? What is necessary?

you decide what current is safe, say 1 amp.

Then R = E/I where E is the battery voltage, and I is 1 amp in this case.
Power dissipation is E*I

You can calculate how long it takes to charge, by 6*R*C, and if that is too long, you can think about a smaller resistor, but 1 amp will charge most caps quickly.


But, the easier way, unless you are dealing with huge caps or very high voltages, is to just use a 100 ohm 5 or 10 watt resistor for everything.

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It would be helpful to know what size capacitor and to what voltage you wanted to charge it to. Basically you charge a capacitor by supplying a current to it. As you do the voltage increases up to the charging voltage compliance limit.

If you wanted to charge a one mcrofarad cap to 10 volts it would be quite different than if you wanted to charge a 10 Farad cap to 2 volts.

You can use a multimeter to measure the increasing voltage on the cap as you charge it. You would use a DC power source to supply the charge, through a resistor to limit the surging current.

Don't exceed the voltage rating of the cap and be sure to observe the cap's polarity!