Browse by Category
YOU ARE HERE: e-Battery Knowledge Base » Laptop Battery & Accessory » Calculating laptop battery run time

Calculating laptop battery run time

Laptop batteries have two main ratings on them: Volts and Amperes. Because size and weight of laptop batteries is limited when compared to larger batteries such as car batteries, most companies show their ratings with Volts and Milliamperes. One thousand Milliamperes equals 1 Ampere. When buying a battery, select batteries with the most Milliamperes (or mAh). Batteries are also rated by Watt-Hours, perhaps the simplest rating of all. This is found by multiplying the Volts and the Amperes together. For example:

14.4 Volts, 4000mAh (Note: 4000mAh is equal to 4.0 Amperes).

14.4 x 4.0 = 57.60 Watt-Hours

Watt-Hours signifies the energy needed to power one watt for one hour. This?laptop battery can power 57.60 watts for one hour. If your laptop runs at 20.50 watts, as an example, this laptop battery could power your laptop for 2.8 hours.

How helpful was this article to you?

Related Articles

article I just received my NiMH batteries. Do I need to charge them prior to using them for the first time?
Yes, before you use your new NiMH batteries for...

  11-5-2007    Views: 868   
article How long will my battery lasts between charges?
This is the most famous client's question, and...

  8-14-2007    Views: 1741   
article Why my camera reports a low battery after only ten minutes of use?
Digital cameras are power high-drain devices....

(No rating)  8-11-2007    Views: 515   

User Comments

Add Comment
No comments have been posted.

e-Battery Knowledge Base content at is only for reference. does not evaluate or guarantee the accuracy of any e-Battery Knowledge Base content.

Copyright 2007