batteries

[IlovePascal]

here's one thing iv neva had a concrete answer for, only ''I think''s everytime.
Can anyone tell me whether it is better to use up completely a battery every time before charging it again or if it's better to charge it up little bits often???? Does it depend on the chemicals used? on the type of battery (cellphones, rechargeable cells, ipods)????

[tanffn]

NiCd – has the crystallization / “memory” problem, therefore you need it to be completely depleted before charging it.
Zinc – has no problem of this sort (now days you’ll find this kind of batteries only in cars)
Li-ion – I’m not sure but I think it has a limit in years / number of recharges. So its better to wait between recharge but the battery efficiency won’t be effect if you don’t (unlike NiCd). You’ll find this battery in most of the cameras ipods etc.

[AthenaOfDelphi]

Zinc/Carbon batteries aren't strictly rechargeable... that said I did see a recharger for them many years ago, BUT, they have to be trickle charged at a very low current otherwise they explode.

Alkaline (Duracell to name one) are the same as Zinc/Carbon but last longer. Not sure whether its possible to recharge these.

So, in short don't attempt to recharge ZincCarbon or Alkaline batteries.

Lead/Acid (Various forms) are the type used in vehicles, alarms, solar electricty installations, boats, UPS's etc. They are pretty rugged but do require different charging methods depending on the cell construction. You should not discharge them below around 50% otherwise their life will be shortened, but properly treated a lead acid cell can last for 10-25 years.

As Tanffn says, NiCd's do suffer the memory problem.. BIG TIME. They should be fully discharged before being recharged. You should also bear in mind that if you trickle charge them (16 hours) they will last longer than if they are fast charged. They also have issues about long term storage... IIRC, if you leave them stored for a long time in their discharged state, you can kiss goodbye to them as they end up being incapable of retaining a charge. You can regenerate NiCds to a point, but its a long slow process and goes something like this... trickle charge, fully discharge, trickle charge, fully discharge and so on.

Li-Ion are great and from what I can gather don't suffer memory problems, but as far as I know, they do have a finite life in terms of charges. These are used in all sorts of situations... as Tanffn says, Ipods etc. Laptops. My Logitech MX1000 has these permanently fixed inside.

NiMh (Nickel Metal Hydride or something like that) are also dam fine. They have massive capacities in small size and don't seem to mind being fast charged. If I were using them for a digital camera... these would be my choice. I don't think they suffer memory effects... Spirit's MX-700 has these in it... overall, they get treated ok as she generally only recharges when they are dead, but they have had to be replaced (can't remember the exact age of the mouse, but it is in excess of 3 years old).

Overall though I would say that for the common rechargeables (Li-Ion, NiMh, NiCd) it is much better to use them fully before recharging because ultimately they either have the memory effect or a finite life.

[IlovePascal]

:wink: :wink: :wink: cheers!

[DGL-luke]

Isn't it with Li-Ions that their chemical structure dissolves dependent on temperature, so they have a usage time limit, not (only?) a recharge count limit?

[AthenaOfDelphi]

Not sure.... most of my in-depth knowledge (if you can call it that) relates to lead acid accumulators that I've designed charge electronics for. A quick google would probably get you some very detailed information.

[LP]

Here's some stuff I've learned about Li-Ion batteries: Li-Ion batteries lose their charge ability with time. I don't remember exact numbers, but it is about 10% of charging ability per year if you store the battery at 40% charge (optimal for storage).

Also, they lose their charge quicker with time at higher temperatures (common in laptops). In some equipment you can't easily replace the battery, like in iPOD (Apple seems to have a replacement policy, but they actually replace the entire iPOD, AFAIK), so before buying check the date of production - don't buy Li-Ion powered equipment that has been in storage for long time, even if its new.

Also, Li-Ion batteries are kind of dangerous (AFAIK they need to pass some special control before even leaving the lab) and they may explode either with overheating or having a very low charge; although, they have a circuit that disconnects the battery at very low charges (that is why you may get your battery unusable if you discharge it completely).

Li-Ion batteries also have issues with overcharging, which tend to lose the charge ability *very quickly* when being overcharged.

My suggestions are:

a) If you don't use the Li-Ion battery, keep it stored at 40% charge in cooler place. I remember reading that storing the battery in the freezer could slow down the "aging" process, but because Li-Ion batteries are hazardous, I'd avoid doing that.
b) Li-Ion batteries lose their charging ability with time permanently, so check production dates to buy only *recent* Li-Ion based equipment.
c) Keep Li-Ion battery changed in 20%-80% range to slow down the process of losing its charging ability (below 20% or higher than 80% battery loses its charging ability much quicker).
d) Don't overheat, discharge completely or overcharge Li-Ion batteries.
e) If you have Li-Ion battery stored for a long time, recharge it periodically to avoid the complete discharge (remember that battery slowly loses its charge).