charging rechargeable batteries

is it better to wait until batteries are depleted fully, and then recharging, OR is it fine to recharge batteries when it's half full or partly full?
i'm referring mostly to laptops, mp3 players, phones and the like. i guess i'm slightly concerned about improper charging.

it's the fucking same

otay

Some batteries have memory, somee don't look and see what kind of battery you use for each device. Plan your resulting behaviour accordingly.

Lithium Ion - Recharge whenever you can, fully draining the battery damages its capacity.
NiMH/NiCd - Let them drain fully before recharging, recharging when there is still a charge left will damage the capacity.

NiMH doesn't have memory problems.  With the right charger (slow, multiple charging method switching, etc.) you can top them off regularly without worries.

talking of batteries, what the hell happened to the magical 'fuel cells' that everyone was spouting off about around a year ago??

The memory effect is a myth. The damage caused by recharging NiCad/NiMH batteries before they're depleted comes from being overcharged in crappy rechargers.

>>8
As already stated, memory effect is very real for NiCd and not a problem for NiMH.  It can often be reversed, and bad chargers might make problem worse, but to claim that overcharging is to blame isn't right.

If you have experience with smart chargers not killing your NiCd batteries when you forget to discharge them fully first, you might be benefitting from the fact that some chargers have a full discharge mode specifically to avoid/fix memory effect on NiCd.

>>9
No, the memory effect is not real, or at best very rare under normal circumstances. What people call the "memory effect" is actually voltage depression, where the battery's voltage drops off suddenly (which appears to anything with a battery meter as a sudden drop in the battery's charge level). It can be fixed to some extent by doing cycles of full discharge/full charge, which is why the better battery chargers have that feature. Strictly speaking the "memory effect" refers to a different problem that occurs only when a battery is discharged to the exact same level repeatedly (as happens on satellites that spend a consistent amount of time in the earth's shadow during their orbit).

>>10
I fail to see where we are disagreeing, except that you keep saying that it isn't a problem but that "it can be fixed" regardless (with a fix that I already mentioned), and that >>8 also somehow also claimed that *problem* affected NiMH as well (which it doesn't).

There is a very good reason that many of today's better cordless phones no longer use NiCd.  Many people are accustom to putting their phones back on the charger when not using it, leaving it there most of the time.  Topping off a NiCd when it hasn't fully discharged like this leads to memory effect, especially when discharged to the same level repeatedly.  In cases like these, where such afflicted NiCd batteries are not of a standard form factor and for which external smart chargers (processor-controlled) are not easily obtainable, the typical end user usually ends up chucking the battery.

>>5
I take it that Lithium Ion is the kind of battery one finds in a laptop, right?

>>12

Right.