Author Options:

The rite resistor to charge this super capacitor. Answered

    Hello I was wondering what resistor you guys would recomend for use in a capacitor charging circut. I can follow common sense for a small 160uf 300v photo capacitor. But this cap has a rating of 3,700uf and 600v. And considering its in issue, (which I believe it may be,) assume your giving it 18v of power from let's say... a drill battery.

                                                     Thank you.


The forums are retiring in 2021 and are now closed for new topics and comments.

11 years ago

No "right" answer for this, of course. We don't know your requirements--length of charge time, etc. Or the max current draw the battery can handle--that's the single largest safety concern (for charging the cap, anyway.)

Try plugging values into this cap charging calculator.

As a baseline, let's guess 100 ohms. That yields:
-- max current draw of 180mA, which should be within the safe range for the battery. You'll need to check this, though.
-- a time constant (RC) of 0.37 seconds

The charge (Q) should approach maximum somewhere around 4RC (four times the time constant.) Or about 1.5 seconds charge time.

You do realize that the max voltage of the charge is the voltage you feed it? Your cap may have a 600V rating, but you won't exceed 18V with this setup...