Small Portable Battery Charging

[pjphilli (Peter)]

Hi

With the old NiCad portable batteries we learned that the battery should be fully discharged before recharging because of "memory effect" of charging a partly discharged batterty.

I am wondering what charging procedures apply to modern batteries such as NiMH and Lithium Ion?

For instance, when at home I usually let my IPad (Lithium Ion) battery
fully or near fully discharge before completely recharging. However, when I take it out I like to top up the partly discharged battery so that the IPad keeps working for the entire outing. I see that Apple advises letting the IPad battery discharge fully and then recharge at least once a month.

So is there a problem (or "memory effect) with battery life if NiMH or Lithium Ion batteries are recharged when not fully discharged?

Cheers Peter

[MrB (Simon)]

Originally Posted by pjphilli

I see that Apple advises letting the IPad battery discharge fully and then recharge at least once a month.

My understanding of this is so the battery management chip can recalibrate.
With many partial charge/discharge cycles it can report a false state of the batteries remaining charge.
The occasional full charge/discharge cycle allows it to know the limits and then calculate and report the remaining capacity better.

As far as I'm aware memory effect doesn't exist for lipo's (I don't believe it existed for NiCd's and NiMH's either, but that's a long story), however there is a current debate on whether lipo's benefit from a special charge for long term storage.

[pjphilli (Peter)]

Thanks for your info Simon.
Cheers Peter