Battery Q&A: Memory Effect & Voltage Depression

  • Thread starter mister_okay
  • Start date
  • Tags
    Battery
In summary, the memory effect is a problem with non-uniform plating of the electrodes inside the battery, voltage depression is mistakenly labeled as the same, and it is possible that your player will cause it to drain a bit faster.
  • #1
mister_okay
20
0
Hello everyone:)

I have questions regarding the "memory effect" and voltage depression.
1.) Could someone explain to me in layman's terms exactly what they are? I don't quite understand the explanation on wikipedia.org.

2.) Additionally, my friend told me that when you turn your mp3 player off (samsung YEPP) you should take out the battery because even with the power off, it will drain. Is this true?
 
Engineering news on Phys.org
  • #2
1) The memory effect is usually attributed to non-uniform plating of the electrodes inside the battery.

2) Your battery will actually drain even if it's not in the player. It is possible that your player will cause it to drain a bit faster, however, depending upon how it is built (is the power switch mechanical, or electrical?) Some electronics constantly consume small amounts of power. If you really want to know, hook a sensitive ammeter in and see how much current it draws when powered off.

- Warren
 
  • #3
But what exactly is the memory effect and voltage depression?
 
  • #4
Mister - one is a specific problem and the other is mistakenly labeled as the same. Since you've read the description and likely aren't building a satellite it doesn't really matter if you're using a widely accepted term (even if technically slightly off).

The battery normally offers a certain voltage, let's say 1.2V per cell. Now when fully charged and unloaded this may be 1.3V. When being used at high loads it may be 1.1V and falling as it drains. If the battery is suffering from being abused, it will read much lower, like 1.0V when you try to use it. A new battery fully charged wouldn't read 1.0V until it was say less than half full, so the equipment could mistake this for a battery that is much less full than it actually is.

This is more of a problem with rechargable batteries because an alkaline battery is generally 1.5V and the rechargable is 1.2V, thus meaning the equipment would need to be designed to work this way (and usually is). But when it comes to figuring out how much charge is left in the battery, its an educated guess and can be wrong. Having batteries that can be slowly damaged and change their behavior increases the likelyhood the guess will be more wrong.
 

FAQ: Battery Q&A: Memory Effect & Voltage Depression

1. What is memory effect in batteries?

The memory effect is a phenomenon where a battery's capacity and voltage decrease over time due to repeated shallow discharges. This is commonly seen in nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) batteries.

2. How does the memory effect affect battery performance?

The memory effect can cause a battery to have a lower capacity and voltage than its original specifications, resulting in shorter runtime and reduced device performance. It can also lead to premature battery failure if not addressed.

3. Can the memory effect be reversed?

Yes, the memory effect can be reversed by fully discharging and then fully charging the battery several times. This process is known as conditioning and helps to restore the battery's original capacity and voltage.

4. What is voltage depression in batteries?

Voltage depression, also known as voltage sag, is a temporary decrease in a battery's voltage during high current discharges. This can be caused by factors such as high temperatures, old age, or high internal resistance in the battery.

5. How can voltage depression be prevented?

Voltage depression can be prevented by using a battery with a higher capacity than what is required for the device, avoiding high temperature environments, and properly maintaining and charging the battery. Additionally, using a battery with a lower internal resistance can also help prevent voltage depression.

Similar threads

Replies
26
Views
3K
Replies
5
Views
4K
Replies
6
Views
12K
Replies
1
Views
3K
Replies
26
Views
8K
Replies
13
Views
1K
Back
Top