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What Should I Consider When Buying a Laptop Battery?

Katharine Swan
Katharine Swan

When choosing a laptop battery, you should first make sure that it is compatible with your computer, and then consider the materials it's made out of. It's also best to look at the power rating and service life, since these have a large impact on its performance and lifespan. Additionally, you may want to consider whether you want a brand name or generic replacement, as well as whether you want a new battery or a refurbished one. Whichever one you choose, you should also look at any warranties offered, and make sure that it complies to safety standards.


Brand name and generic batteries are available to correspond to the model of laptop computer.
Brand name and generic batteries are available to correspond to the model of laptop computer.

The first thing to look for when buying a new laptop battery is compatibility with your computer. Most are made to work with specific models of computers, and have this information listed in their product descriptions. To make sure that one will work with your computer, you'll need to know the make and model number of your laptop; if you don't know this offhand or don't have the necessary paperwork, check the inside of your laptop's battery compartment while it is off and unplugged. You may also find the part number of the battery, located on its casing.


A couple using a laptop running on battery power.
A couple using a laptop running on battery power.

You should also consider the material that the battery is made out of: Nickel Cadmium (NiCad), Nickel Metal Hydride (NiMH), Lithium Ion (LiON), or Lithium Ion Polymers (Li-Poly). NiCad batteries are largely obsolete, since they are very heavy and don't last very long. NiMH batteries last longer than NiCads, but significantly shorter than LiONs and Li-Polys. They also weigh more, and have the "memory effect," which causes them to lose the ability to fully recharge.

Make sure your new laptop battery is compatible with your computer.
Make sure your new laptop battery is compatible with your computer.

Generally speaking, LiON and Li-Poly batteries are the best choice, as long as they're compatible with your laptop, since they are light, last longer than NiMHs, and are about a third lighter. They also charge more quickly, and are also more environmentally friendly. Regardless of which type of laptop battery you end up getting, you should make sure that the cells are manufactured in such a way that they meet international standards of laptop battery safety, like those designated by Underwriters Laboratories (UL).


The capacity, or power rating is another important consideration. This is the amount of power that the battery can produce, and is usually written in milliamperes (mAh). The greater the capacity, the longer the battery can run before it needs to be recharged, so look for the highest mAh number. Most new ones are rated to at least 5,000 mAh.

Service Life

Like other technological products, laptop batteries have a designated service life — the length of time that they're expected to work optimally. This is usually written in terms of cycles, with one cycle consisting of completely running the battery out, and then completely charging it again. Most are are able to go through between 300 and 1,500 charging cycles, and can be used after the maximum cycle count is reached, but may not hold a charge as well. Some computers come with a cycle counter built in, but there is free cycle counting software is also available online for download.

Branded vs. Unbranded

You may additionally want to consider whether you want to buy a brand name laptop battery, like the one your laptop came with, or a generic replacement one. Many brand companies and companies that make generic batteries get their components from the same manufacturers, so it may not make a huge difference, but some brand name versions meet more rigorous safety standards than generic ones, and some do use different, higher quality components. Also, some brand name versions come with better warranties than generic ones. Branded batteries do tend to be more expensive than generic ones though, so if you compare a brand name laptop battery and a generic one and find them to be largely similar, then you may want to go with the generic one.

New vs. Refurbished

Besides the issue of branding, you should also think about whether you want a new laptop battery or a refurbished one. Though some refurbished ones are very good and are often much cheaper than new ones, it's a little risky to buy refurbished, since you don't really know how old the battery is, and it may die suddenly. Also, many refurbished batteries don't come with very good warranties, so it may be worth it to just get a new one, especially if you use your laptop a lot.

Discussion Comments


Hi there.

Thanks for the advice, helpful. Especially that about preferring lithium technology to older materials.

One thing though:

mAh means milliamp hours, not milliamperes. It's the amount of energy stored, not the power.

Current x voltage is power. Power x time is energy.

Voltage is fixed for a given battery type (11V, 14V etc) so the only variables are current and time. If your machine is drawing higher current then the battery will last less time, hence the relevant feature of the battery is expressed as mAh. So if you have a 5000 mAh battery it can deliver say 0.2 amp (200mA) for 25 hours, or 0.1 amp for 50 hours. (In theory. I'm sure that in reality the efficiency of the battery will vary with the usage pattern)

I'm not a computer geek, but I am an old engineer, so energy and units is one of the few things I do know about.

All the best



I bought a battery from an online store. It has been a year and a half now, and it works well with my laptop. The price was also very attractive.



I work for Max Capacity (Brand of laptop battery) and an online laptop battery retail outlet. We are basically a newer company located in the US that specializes in building very high end replacement laptop batteries designed to compete with and outperform OEM.

I'll share a bit about what some of the main differences in quality are, and what to possibly to look for when evaluating different batteries.

About capacity and service life: A typical generic 6 cell laptop battery only holds about 4400mAh of power, which is quite low when compared to the newer generation of cells which store 5600mAh or even 5800mAh in a 6 cell battery. For example, a 5800mAh battery can power your laptop for 40-50 percent longer on a single charge.

And with respect to service life, most generics only last about 300 charging cycles, compared to 600 to 900 charging cycles for the newer generation of cells. This 300 charging cycles typically means an average service life of a little over one year, while 900 gets over three years before a new replacement is needed.

The result is you wind up paying $35 per year for replacement batteries that offer very low power capacities when one could buy a high capacity battery that lasts about three years and have the latest safety features incorporated into them.

So in the long run over a two to three year period, lower cost batteries tend to cost the same as as a 5800mAh battery that performs better and incorporates the latest safety innovations.


Because the battery needs more capacity to be used for much longer, and also the quality is also very important. I recommend a good supplier to you. My laptop is made in China, and the original battery 3E01 is only 2200mAh, is too short to use. So I needed to buy a longer used battery. I asked more suppliers and finally I got one 4400mAh battery of my own, and it only cost me $60.


I bought my IBM laptop battery online. So far it is good. I also bought an extra charger for my laptop from them.


I bought one made by Microdigital. So lucky, it's so good so far.


When buying a laptop battery, you will probably only have one or two choices that fit your computer. Choose the battery with the longest life available for your computer. I agree with it.


I needed a battery quickly to continue my web design and ordered it online It was there in under 24 hours. They had a large variety as well.


I fully agree with the li-ion comment. I'm also looking for a new battery for the same reason.


Who ever said you don't need to condition "li-ion" batteries is full of it. I am searching for a new battery as we speak because of that reason- totally shot my battery after I started leaving it plugged in at work.


I learned much from above articles. what i am interested in is whether it is safe or not when buy laptop battery from an online shop. I want to buy a battery for my IMAC and found a website where all the laptop batteries were much more cheaper than items elsewhere. I am so excited but also worried about the quality, so can anyone give me some advice? Many thanks!


What should I consider when buying an emergency battery jump starter? Three characteristics that are advertised are amps/hour, peak amps, and cranking or continuous amps. These are factors to consider when purchasing an emergency auto battery jump starter and it would be useful to understand what they mean so you purchase the best jump starter for your money.

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    • Brand name and generic batteries are available to correspond to the model of laptop computer.
      By: kalpis
      Brand name and generic batteries are available to correspond to the model of laptop computer.
    • A couple using a laptop running on battery power.
      By: Yuri Arcurs
      A couple using a laptop running on battery power.
    • Make sure your new laptop battery is compatible with your computer.
      By: .shock
      Make sure your new laptop battery is compatible with your computer.