Am I correct in assuming that charging my PDA when it is down to, say, 25% of full charge will result in longer battery life that throwing it on the charger every night?
That depends upon the battery chemistry. For NiCd cells, it’s essentially true. NiMH and lithium cells are much more tolerant of frequent charging, however.
But IMO they are still prone to the effect. I think you shorten the overall lifespan (and the amount of time it will last on one charge) if you are constantly topping it up.
If the device regulates the charge, then it doesn’t matter. Blackberry and PDA devices regulate the charge. You won’t be cooking the cells like you would with an old NiCd charger that just pumps current w/out controlling it.
NiMH and LiON batteries don’t like being deep-cycled, just the opposite to NiCd’s.
IMO all this should be hidden from the consumer. A consumer sholdn’t need a degree in chemistry to properly charge his PDA or MP3 player.
NiMH devices that I’ve had ALL work better if the batt is fully discharged before being fully charged… I’ve tried the topping up method and found that my batteries drained much quicker when they’ve been topped up. I haven’t owned a nicd battery for years. all NiMH
What would be considered deep-cycling for a Li-ion battery (my pda displays charge as a percent) ?
Transparency costs money.
LiON’s prefer to be maintained at full charge. This is clearly impossible to achieve in practice and use the device as portable but the advice I have received is to recharge as soon as possible on any occasion and deplete the battery as little as possible.
Replacement batteries are so expensive I think it is worthwhile taking as much care of them as I am able.