電池記憶效應：沒充電充過頭就沒有記憶效應。

http://www.repairfaq.org/ELE/F_Battery_info.html

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[Will regular partial discharges with complete recharges limit the charge-life of the battery?]

No. There is something known as the "memory effect", which can limit NiCd battery capacity if the battery is _repeatedly_ discharged to _exactly_ the same partial-discharge level, and then fully recharged, many times in a row. Gates[1] states that the memory effect is almost never seen in practice, because it only occurs if the partial-discharge level is repeated very precisely many times in a row.

There _is_ an effect which can mimic the "memory effect", in the sense that it makes the battery look as if it is losing capacity. This effect, known as "voltage depression", occurs if you over-charge a battery. The battery's output voltage drops from 1.2 to about 1.05 volts partway through the discharge cycle, and this may "spoof" a power-monitoring circuit into believing that the battery is exhausted.

Voltage depression is curable. It can be cured by fully discharging each cell of the battery... INDIVIDUALLY... all the way to zero, and then recharging the battery. You can do this if the battery design allows you to access the individual cells. You can't do it if you can't get to the individual cells, but only to the battery terminals.

Alternatively, you can discharge the entire battery until the total voltage drops to 1.0 volts per cell, and then recharge it... do NOT try to discharge the battery all the way to zero, or you will very probably damage it. This 1.0-volt-per-cell shutoff should be safe (in particular, it leaves a good safely margin for any battery rated at a nominal output voltage of 6.0 or less) and should discharge all of the cells well past the voltage-depression point.

You can avoid overcharging by taking the batteries out of the charger when they've been fully charged. If you need to keep NiCd batteries in a "floating" application... if they must be be kept constantly "topped up" to full charge without human intervention... then you should use a charger which is intelligent enough to switch to a low-rate trickle charge once the battery is full. I believe that a trickle-charge rate of about C/100 or so (e.g. 10 milliampere, for a 1000-milliampere-hour battery) is in the right ballpark - it will compensate for the battery's rate of self-discharge.

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• 記憶效應 是因材料而定的..我是聽電池工程師說的 -rainygan- ♀ (0 bytes) () 07/06/2008 postreply 18:28:03