How to Buy Laptop Battery Packs

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How to Buy Laptop Battery Packs

Travelling with a laptop lets users work and play whilst on the go, whether on the train, at the airport, or simply between school and home. The flexibility and portability of a laptop computer is its main attraction; however, its usefulness lasts only as long as its battery life. Once the battery runs out, a laptop transforms from a multitasking device into a few extra kilogrammes of dead weight that need to be lugged from one place to the next. If planning to work on a laptop for an extended period, having an extra laptop battery pack on hand can prevent such situations.

When shopping for a laptop battery pack, be it a replacement, augmentation, or backup, it is vital that it be compatible with the laptop's specifications, including battery type and power ratings. Furthermore, battery-pack form factor is also model-specific. For these reasons, buyers should have accurate information about their laptops on hand when shopping. There are a few other considerations, such as buying name-brand or generic batteries, that also need to be weighed, before deciding on the right laptop battery pack.

Types of Laptop Batteries

A laptop computer contains a rechargeable battery that is one of four types. Each type is distinguished by the specific chemicals it contains. When choosing a new laptop battery pack, buyers need to pay attention to which type they are buying, as most laptops cannot take a different battery type than the one they come with originally.

Nickel-Cadmium Batteries

An older battery type that is now rarely manufactured for laptops, Ni-Cad (nickel-cadmium) batteries were used in earlier laptop models. They had several disadvantages, including environmental toxicity when improperly disposed of, poor battery life, and what is known as a memory effect, in which batteries that were not fully depleted would remember how long they had been used and only charge to meet that shorter battery life.

Nickel-Metal Hydride Batteries

An improvement on their Ni-Cad predecessors, Ni-MH (nickel-metal hydride) batteries offer longer life, a 10 to 25 per cent larger capacity, improved efficiency, less toxicity, and have far fewer issues with a memory effect. Compared with their Li-Ion and Li-Poly counterparts, however, Ni-MH batteries are heavier and carry less charge.

Lithium-Ion Batteries

Many laptops have lithium-ion batteries, which have a 40 per cent greater capacity than Ni-MH batteries, are more efficient and less environmentally toxic, and have a low self-discharge, meaning a longer shelf-life when fully charged. Moreover, they are more compact, have no memory effect, and do not need to be fully charged to perform optimally.

Lithium-Ion-Polymer Batteries

Lithium-ion-polymer batteries are a modification of Li-Ion batteries. The difference between the two is that Li-Poly batteries have a solid ion conductive polymer, instead of the liquid electrolyte in Li-Ions. The result is a safer, more lightweight battery that can be as thin as a credit card. Li-Poly batteries cost more to manufacture, however, and have an inferior energy density compared to their Li-Ion cousins.

Determining Laptop Compatibility

A major concern for anyone shopping for a laptop battery back is whether it is compatible with their laptop. It is very important that the battery pack match the manufacturer's specifications. Batteries are generally designed to work with a specific make and model of computer, and should be matched accordingly. Therefore, shoppers should have the following information on hand:

  1. the laptop manufacturer, such as Toshiba, Sony, HP;
  2. the laptop model number, which includes the series and specific model number; for example, Sony VAIO VGN-FZ90S; and
  3. the battery part number itself.

Precise laptop model information is usually located in system information on the computer itself, which can be accessed by opening the system properties window. As for the battery part number, this should be written on the existing battery itself. Make sure the computer is unplugged and turned off before opening the battery compartment to check.

How Many Battery Cells is Enough?

One of the prominent specifications for a laptop battery pack is the number of cells it contains. Basically, each cell holds a certain capacity, and the more cells, the more charge the battery can hold. For example, a nine-cell battery pack has 50 percent more capacity than a six-cell pack, and a 12-cell pack has double the capacity of the six-cell. In general, the more cells a battery pack has, the longer its battery life. Some manufacturers specify their batteries in terms of number of cells, while others express them in Watt-hours (Wh), discussed below.

An Overview of Laptop Battery Pack Power Ratings

Aside from number of cells, batteries have three main power ratings: voltage, capacity, and Watt-hour. In general, the manufacturer specifications should indicate what power ratings the laptop can handle.

Voltage (V)

A battery's voltage expresses its potential energy in Volts (V). Common voltage ratings for laptop batteries are 7.2V, 9.6V, 10.8V, 11.1V, and 14.4V.

Capacity (mAh)

The battery pack's capacity is expressed in Milliampere-hours (mAh), where one thousand mAh equals one Ampere-hour (Ah). Typically, batteries with more cells have a higher capacity rating.

Watt-Hour Rating (Wh)

Watt-hours (Wh) are calculated by multiplying the voltage and Milliampere-hour ratings, and then dividing by 1,000. Watt-hours make it relatively easy to estimate how long a battery can last for a given laptop, given the number of watts the laptop requires to run. Simply divide the number of Watt-hours by the laptop wattage requirements, and the result is the number of hours the battery can run the laptop.

Choosing Between the Original Manufacturer or Third-Party Battery Pack

Battery packs for laptop computers can come with a high price tag, especially if they carry the same brand as the laptop. In order to save money, buyers may be considering a third-party, generic battery pack. Considering that many laptop brands use battery components from the same manufacturer as third-party companies, this seems like a good choice. However, it should be approached with caution, for a few reasons.

First, battery packs sold with the laptop brand have been subject to rigorous safety inspections. While this may be the case with generic batteries, it is not certain. In addition, there have been instances where third-party companies have falsely labelled their batteries. Overheating is a real concern: a low-quality battery pack that is not made to specification can jeopardise the laptop as well as personal safety. Finally, even big-name manufacturers at times need to recall batteries. It is good practice to register new battery packs with the company they are bought from, just in case.

Buying Used or Refurbished Battery Packs

Another money-saving option that some may consider is to buy a used or manufacturer-refurbished battery pack. However, this is not generally recommended, unless the laptop is used only occasionally. Used and even refurbished battery packs do not hold as much charge as new ones, and may unexpectedly fail without warning.

Additional Considerations and Options

Replacing a single battery pack, or buying a backup, is fairly straightforward. But for those who are trying to augment their existing battery pack, either with a second internal battery or an external, portable battery pack, there are a couple things to keep in mind. First, remember that adding battery power means adding weight, and the more cells a battery has, the heavier it is. This may be a fair tradeoff for those who require an extended uptime whilst far from a mains outlet. Another potential issue is that there may be certain requirements for adding a second internal battery, such as using a lower-power operating system. Buyers should check for these things in advance so as to avoid any unpleasant surprises.

How to Buy Laptop Battery Packs on eBay

If you are looking for a laptop battery pack to help you get more uptime from your computer, be sure to browse eBay's extensive selection. Beginning on the eBay home page, enter keywords into the search bar, such as "Sony laptop battery pack". You may want to include your laptop's model, as well. Once you have your search results, you can refine them according to things like capacity, number of cells, brand, and price range.

Read Item and Seller Information

Before purchasing an item, be sure to look closely at full listing. Check carefully for things like item condition (new, used, or refurbished), specifications, and any additional postage fees. With battery packs, it is important that you buy from a seller who is reliable and reputable. For that reason, you should also check the seller's feedback score and look through comments left by previous buyers who purchased battery packs from them. A good deal of positive feedback is likely an indication that you can have confidence in the seller and product. Top-rated sellers complete a high rate of transactions and maintain an excellent standard of customer service.


Whether replacing an old battery, augmenting the power of the present one, or buying a backup for long trips, battery packs are vital for keeping a laptop up and running. Buying a laptop battery pack requires attention to the computer manufacturer's specifications, to ensure that the battery's power ratings and form factor are a perfect fit.

There are four types of batteries used in laptops, although generally speaking lithium-ion batteries are dominant in newer laptops. In most cases, it is not possible to replace one type of battery with another. In order to find the right battery pack for a laptop, buyers should have their PC's make and model information, as well as the part number of the current battery. Battery pack power ratings help buyers assess how much battery life they can expect when using their laptop. It is recommended that consumers opt for new battery packs from the same maker of their laptop, although there are some generic batteries that are equally high quality. Following these guidelines can help buyers find the right battery pack to keep their laptop going and going.

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