Here’s a nifty trick that will show you the wear on your Dell laptop battery.
It requires that your battery have the self-test button on it with the 5 LEDs.
- You can show the percent charge remaining by pressing the self-test button.
One to five LEDs will light up showing the approximate level of charge (around 20% for each LED that shows up.)
Every-other (on-off-on-off-on): The battery fail-safe has triggered and the battery is unusable.
- You can show the percent wear by holding the self-test button for about 5 seconds.
The LEDs will light to show thecharge just like in step the point above, but after 5 seconds the lights will go off for a moment and a new light pattern will display. (No lights IS a valid display.) This indicates the percent of battery WEAR on increments of 20%.
If you get no lights, either the battery has very little wear (charges completely) or is “dead” (can’t be tested/doesn’t charge at all).
5 lights: The cells are completely worn and will not hold a signifigant charge.
Of course, you can always go into your systems BIOS and take a look at the battery health there, but this is great is you’re picking up a battery and want to check it out before installing it in your system.
This test only works on Dell batteries (as far as I know — other manufacturers may have something similiar) and only genuine Dell batteries. Not cheap imitations.
You can find more information on Dell batteries at the Dell Laptop Battery FAQ