Battery degradation

While my M1530 is plugged in, does the battery life still get worse or is it only while I am using the computer on its battery? Only because the majority of the time I want to use my laptop as a desktop and was wondering whether it was best to take the battery out whilst it isn't in use.

 

Batteries will degrade over time no matter what. But they degrade faster while you use the battery over and over. It will still degrade even if you leave it out of the laptop.

 

Taking the battery out will marginally improve it's life.

In theory the best way to store it is at 40% of its charge in a cool (5-10C) place. In practice I'd just leave it in the laptop.

 

Have a little read of the battery guide for more info:

http://forum.notebookreview.com/showthread.php?t=91846

But it's best to discharge it to about 40-50% and store it in a dry bag in a cool, shaded place. Leaving it in does make it degrade faster and they're a lot of money and hassle so I recommend making it last as long as possible.

One up for having a battery is that if the power goes off, you've got a while to save your work but in practice it's better to get an APC and take the notebook battery out.

Have fun!

Matt. I

 

I have a dell 4 year warranty taken out on the xps im expecting tomorrow, I know the battery will degrade, but if at some point it just stops working, do you think i can get a replacement?

 

Batteries are considered consumables and have a 1 year warranty. If it stops working completely within a year they'll replace it but anything beyond that is considered normal wear and tear.

 

I think you're worrying too much oocon!!!

Enjoy your new laptop!!! In three years if you're even thinking of still keeping your "old" M1530 instead of upgrading to the latest and greatest, that's when you can go out and "splurge" and buy a new battery

 

Batteries any more are pretty smart in taking care of themselves so you won't have to take any special care with them. Just know the more you use it the faster it will degrade.

 

i blame the law of entropy

 

Very interesting. Thanks for posting that judgedee.

 

For my M1330, I have two batteries originally. Within three months, one of them lost about 20% of its capacity. Then I called Dell and the TECH SUPPORT dept. sent me a replacement battery (I think it's a refurb one). After receiving it, I returned the old one then found out that the replacement battery had an even LOWER capacity than the previous one. This time I called CUSTOMER CARE and the rep. sent me a NEW battery (manf. in Jan 2008) with nothing needed to be returned. So now I have THREE 9-cell batteries of M1330 =w=

 

The batteries in laptops now are all lithium ion polymer cells.
These batteries are 3.7 volts per cell when they are dead. A 3 cell lithium ion polymer cell (or lipo) is 11.1 volts dead but over 12 volts fully charged.

What happens to the battery over time is that the charger does not perfectly balance the voltage in each cell causing one of the cells to reach its maximum voltage while another is not yet charged. All the charger does is charge to a certain voltage. One cell may be higher than it should and another lower than it should but the voltage of the overall battery is where it should be when fully charged. By using the battery for a certain amount of time, the current draw is equal from each cell. This means that the same amount of voltage is taken out of the fully charged cell as it is from the cell that is slighly less than fully charged. Over time this builds up and one of possibly a few cells get lower and lower voltage when fully charged this causes the battery to not be able to reach it's full potential over time.

Because a cell can only hold so much voltage, over time the batteries voltage when fully charged is less and less. Once a lithium cell reaches a voltage of below 3.7 volts it is very rare that this cell will ever charge again. I have a laptop with this type of battery and 2 of the cells died to below 3.7 volts. so the battery never reaches a full charge and now over a few years all of the cells are dead. Literally if you have the battery in and unplug it from the wall it does not last any longer than if the battery is out. It is instant.

Basically to get the longest use of your lipo battery do this

-when you first receive your laptop, fully charge the battery without using it (as hard as this is to do, because you want to play with your toy, it will help in the long run)
-for your first 5 batteries or so, do not drain the battery below 40% once it reaches a charge anywhere between 40% to 50% start charging it. Wait until it is fully charged then unplug the charger.
-after this you can charge it while it is at any percent an it will cause minimal long term effect but lipo batteries need conditioning (breaking in) to reach their full potential)
-never when using your laptop for long periods of time decide to just leave it plugged in. This is the worst thing to do. over a long period of time your battery will develop a memory. lipo do not develop this as easy as nicad or nickel metal hydride batteries but they do do it. This means if you leave your battery plugged in for say a month straight your battery will think that fully charged, is its maximum discharge which is a hard concept to grasp but it is true. When you unplug it the battery will think that it can not go below the voltage it is at and die very fast. (this can be fixed to an extent by cycling) which is charging to 100% discharging until your laptop is about to shut off.

If you are using your laptop for a long period of time and do not want it to lose power then take the battery out and plug it in. Hope you understand this. It may take a few reads through (which will be really boring to read this more than once ) but it will save your battery.

Still get a new one for free a few weeks before your warranty is up (one year for the battery) just say it doesn't last near as long as it did when you got it and you'll get another one. You can only slow down this degrading. you can not stop it.