Hello!

I have several questions regarding proper usage of rechargeable batteries:

1. Some people say that it is wise to keep the cells in a refrigerator when not using them, others say that low temperatures might damage the batteries. Which statement is right?
2. I have been told that -∆V is good for NiCd cells, but for NiMH, the switch-off would occur too late. Which system would you recommend for optimal charging?
3. Most people say that it is good to unload the batteries before charging in order to avoid memory effects. Other people say that unloading them might reverse the polarity of the cells. When should I charge the batteries then?
4. Do you think fast chargers (which claim to charge 2 Ah cells in 15 minutes) are good?

Regards,
Sebastian Mares

Since you can read german, i sent you some interesting remarks from c't magazine via e-Mail. Have fun!

Danke!

NiCad has crystalline memory issues. It is best to discharge them fully first, then recharge.
NiMh and Lithium do not suffer from memory problems. The can be charged at any time.
Heat is the enemy of all of these batteries. I do not believe it is necessary to store them in the refrigerator. Any benefit is minimal.
I have had excellent luck with the PowerEX batteries I bought. They work great in my son's portable video game and my digital camera. They got very good independent reviews. The MH-C205GT charger has worked like a champ.

Thomas Distributing

Okay, i'll put some answers here for everyone:


Cells really can last longer in the fridge (not in the freezer!) if you put them into an airtight bag to avoid condensation, because the lower the temperature, the slower they self-discharge. Of course they need to get warm again before they can supply their full power.


Any newer -∆U charger is ok, -∆U with timer-shutdown is better, -∆U with temperature-check is even better, CCS ("Computerized Charging System") is best.



The results of NiCd memory-effect are often overestimated and are confused with capacity losses from overcharging and deep discharging as well as normal aging of the cell. Manufacturers of rechargeable batteries find this convenient. Blame for premature failures can be shifted to the user. Should a memory effect really occur, you can get rid of it with a few discharge/charge cycles. Don't use the discharge-function for NiMH-batteries though.


The simple ones aren't. The good ones, with the aforementioned features, should make no problems.

2.9) Does the memory effect exist?
<Flame shields on> YES
Just as everyone is running around and saying that the memory effect is a myth, here I am, saying that it is true. OK, so, why is this? First of all, the term memory effect is quite unscientific. People tend to attribute any failure of a NiCd to memory.

Full text here:

NiCd Battery FAQ V1.00

The full text describes it good. The "memory effect" is not something you should worry about. People should just buy good chargers.

How to treat your rechargeable batteries:

- Do not discharge on the regular. Every discharge/charge cycle stresses the cell. Only use the discharge function if a NiCd battery has noticable lost capacity.

- Do not touch the poles. Sweat has salt which leads to corrosion.

- Only use the same pair of cells together, evenly charged.

- Don't let them drop or throw them around, i.e. in a remote control. Sudden shock can decrease capacity.

- Use a good charger! This is the single most important factor for longevity.