Thread: Best recharge practices.

I’ve heard that it’s best to mostly discharge a battery before recharging. Is this true?
I would like to keep my various devices topped off, for convenience. But, I have several USB battery banks, and could readily alter my charging behaviors in consideration of device longevity.
And, of course, here’s a chance for a battery science lesson.

Originally Posted by GiantEvil

I’ve heard that it’s best to mostly discharge a battery before recharging. Is this true?
I would like to keep my various devices topped off, for convenience. But, I have several USB battery banks, and could readily alter my charging behaviors in consideration of device longevity.
And, of course, here’s a chance for a battery science lesson.

The answer very much depends on the battery chemistry. Lead-acid batteries should be kept topped up for longest life. Just to keep us on our toes, though, nickel-cadmium batteries suffer from the formation of crystals if kept topped up, and must be discharged fully from time to time to prevent loss of operating capacity. Lithium-ion batteries eat themselves at the highest rate when topped up, so keeping them at roughly 50% charge yields the longest shelf life.

A separate consideration is that the "fuel gauge" needs to track a battery's changing characteristics with age, and that requires an occasional full cycle or two of charging and discharging to keep the gauge properly calibrated. Just be careful not to leave lithium batteries in a fully discharged state. Protective circuitry can engage if the voltage drops too low, forever preventing recharge (persistent deep discharge can encourage the formation of internal short-circuits in lithium chemistries, so such circuitry is needed to prevent converting batteries into flame throwers).