Bigger is Better, or is it?
To put it simply, more cells means more power. In other words, a battery with a higher cell count means longer life. A 6-cell battery can outlast a 4-cell battery. But does that necessarily mean that one is “better” than the other? Depending on the brand and make of the battery, a 4-cell can last from 1.5 to even 3 hours, but that will vary due to specific details like screen brightness, battery power settings (running on low-usage or maximum-efficiency), playing games or watching DVDs/Blu-ray. Taking that into account, a 6-cell can last between 4 to 5 hours on a single charge. Again, it all varies depending on what you are doing with your laptop, or what you would like to do with your laptop on a single charge.
Difference in Cost
The problem with laptop batteries is that they are not light on your wallet. A 6-cell battery can cost about $65 more than a 4-cell battery. Using Dell as an example, their 4-cell battery starts at about $90, whereas their 6-cells are around $155.
Pros and Cons
A common complaint among some users is that a 6-cell battery tends to “stick out” physically from the rest of the laptop. This can create for a visually awkward appearance to your laptop, and in some cases may be a comfort issue. Ultimately, what it comes down to is how often you will need to run your laptop on a single charge. For example, if you are a student and use your notebook diligently to take notes and do a lot of work on your computer, it may be worth paying the little bit of extra cash to get that extra hour or two of battery life. Additionally, if you like to watch a lot of media - such as playing DVDs or Blu-ray, or if you like to do a lot of gaming, a 6-cell may also be worthwhile as multimedia usage can be taxing on a battery. However if you don’t see yourself unplugging your laptop from its AC adapter often, or don't seem to mind the current life of your battery, then upgrading may not be necessary.
Again, it has to do with what you are planning on using your laptop for, and how often you expect to be relying on the battery.
Tips on Extending Battery Life
There are several ways in which you can extend the life of your battery. Some of these require some minor tweaking, and others are through general usage. In Windows, you will see a battery icon in the far right in the taskbar. Changing this setting to save the most power (In Vista and 7, choose Power Saver) will turn off certain effects such as Windows Aero – if using a version of Windows that is higher than Starter or Home Basic (those versions do not have Aero). Also, turn down the brightness of your screen. The brighter your screen, the more battery life you are using. If you have programs running in the background that you are not using, turn them off. That will clear up CPU and RAM usage, making your computer run more swiftly and require less juice from your battery.
Most importantly, the best way to extend the life of your battery: if you ever unplug it from the AC adapter, then avoid plugging it back in until your battery is almost fully discharged. A common fear is that Windows will completely shut down when the battery life gets low. Not so! When your battery gets low, Windows will warn you, and if it gets lower than 5%, it will go into Hibernation. What this means is that everything that was stored in your RAM from your current Windows session will be stored in the hard drive. So when you plug your laptop back in, and power it back up, you will be able to continue what you were doing before your computer hibernated. Your work will be safe, and your battery will last longer.