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Charging capacitors with different currents? Answered

How does charging a big capacitor with a high current affect it rather than a low current? Certainly time taken decreased. What are other effects, and is it as safe as using a low current?

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Best Answer 7 years ago

Depends on the type of capacitor.
Large electrolytic capacitors that are being charged for the first time after
months or a year of being discharged, should be slowly charged because
the voltage barrier between adjacent plates is a chemical barrier  that must have time to erect the proper withstanding voltage shield or the capacitor may fail and actually damage the plates permanently and short itself out of
existence.
 There after the charge rate will no longer be of worthy of concern.

A

Within the capability of the capacitor to cope with the current it will charge faster - think of it as a bucket and your filling it with water faster flow means faster filling.

HOWEVER as the capacitor fills the filling flow is opposed by the charge in the capacitor and so drops off on an exponential curve.

A capacitor charges in Capacitance x (charging) Resistance time in seconds.
It is considered fully charged after 60% RC has passed. So you can work out the effects of changing the current flow (value of R)

A high, single pulse is OK - every few seconds kind of thing. Repetitive charging (like at main frequency) at very high currents will heat the capacitor and you may destroy it eventually.