Batteries and Chargers: A Guide to Powering Your Laptops and Computers

Steve Webb Steve Webb

Any computer, desktop or laptop, is only as reliable as its power supply. This is why desktop back-up batteries, laptop batteries, and chargers need to be in good shape all the time.

Batteries and Chargers: A Guide to Powering Your Laptops and Computers

When a battery or a charger fails, a new one is needed in a hurry. However, it is not always as easy as simply ordering another piece from the manufacturer. Where desktop back-up batteries are concerned, there are various types and features that a shopper should know about before attempting to choose one.

With laptop powering accessories, consumers generally have a choice between the original equipment manufacturer and third-party manufacturers. Knowing the benefits and disadvantages of each, as well as how to choose a third-party battery or charger, allows a buyer to make a wise purchasing decision. Computer UPS units, as well as laptop accessories such as batteries, chargers, and adapters, can be found at electronic goods stores as well as online at websites such as eBay. By learning to shop for these items on eBay, consumers can take advantage of the widest selection possible.

Uninterruptible Power Supply Units for Computers

An uninterruptible power supply consists of a back-up battery bundled with other technologies in order to ensure that in case of a power outage, the computer could keep running for at least long enough to close any programmes and power down. High-end UPS systems have longer back-up runtimes, allowing one to continue working for hours on end with the power out. Before shopping for a UPS, one should know about the different types on the market, the ways they can connect to the computer, and the features they can come with.

UPS Types

Although many people only know of the standby UPS and the online UPS, there are actually many more UPS types on the market. Each provides different levels of line conditioning and battery back-up to computer systems of different sizes. The size of the system is measured in VAs, or volt-amperes, a measurement closely related to watts. Knowing a little about a few basic types of UPS is essential to choosing the right type.

Standby UPS

The standby UPS is the most basic kind. It provides surge protection and noise filtration, as well as a battery back-up. It is called a 'standby' because the inverter only starts working when the power goes out. This kind of UPS is most useful for home computers and small systems up to 500 VA in size.

Line-Interactive UPS

Line-interactive UPS units have an inverter which is working all the time, unlike the standby UPS. However, it still runs from the mains, and only switches to the battery in the case of a power outage. This system provides more voltage conditioning, and is more reliable than the standby UPS. It used to be significantly more expensive but has been dropping in price. A line-interactive UPS can be used for larger systems than a standby UPS, and is a good solution for small businesses. These units have a power range of 500 VA to 5000 VA.

Online UPS

Online UPS systems are the most advanced. More than one online UPS technology is available but what they have in common is that the power is constantly fed through the battery and the inverter, and the mains is used in case the UPS malfunctions. Unlike other UPS types, there is no limit to the size of the system that can be used with an online UPS. It also provides the highest level of power protection of the three main UPS types.

The table below summarises the characteristics of different UPS types. Use it to choose the most appropriate type.

UPS Type



Ideal Uses


Low cost, surge protection, noise filtration, efficient, compact

No voltage regulation, only for systems under 2 kVA

Home use


Reliable, efficient, offers voltage conditioning

Only for systems under 5 kVA (around 10-12 computers)

Small businesses, servers


Advanced features, highest level of protection, reliable

Expensive for systems under 5 kVA

Large computer systems

As the table shows, any business with more than 12 computers should look at online UPS systems, especially if the business expects to grow. Home users can do with a standby UPS, but get more value for their money with a line-interactive system that costs a little more but offers much more power protection.

Laptop Batteries and Chargers

While a desktop computer generally stays in a single place and is easily connected to a UPS, the same cannot be said of laptop computers. The mobility of laptops means that power has to be reliably supplied from a battery or from the mains through an adapter, which also serves as a battery charger. Laptop power supplies can be divided into two basic groups: OEM products and third-party products. There are advantages and disadvantages to both that are certainly worth noting. Also, one should know about different battery types, as well as how to choose the right laptop charger.

OEM and Third-Party Batteries and Adapters

OEM products are those made by the original equipment manufacturer. These are guaranteed to work with the laptop as long as one buys the correct model of battery or charger. This guarantee is enough to make many people swear by them, despite the much higher price. Third-party supplies, on the other hand, are much more inexpensive, and are made by third-parties to fit certain laptop brands and models.

The general rule is that the lower the price, the higher the risk. However, that does not mean that OEM parts never give trouble, or that a third-party adapters never work. Paying close attention to the compatible laptop model numbers, and looking closely at the warranty offered by the seller, is the best way to buy both the quality OEM parts as well as the more affordable third-party batteries and chargers.

NiMH, Li-ion, and Li-poly Batteries

The most common battery type is the lithium ion battery but many laptops still have the older nickel metal-hydride battery. Lithium polymer batteries are the newest technology and are slowly gaining ground as well. Most laptops take just one type of battery but there are some models that can use both NiMH and Li-ion (or LiON) batteries. When this is the case, LiON has many advantages over NiMH. It has a higher energy density, no memory effect, and a slower loss of charge when not used. Older laptops may also use nickel cadmium batteries, but these are being phased out in laptops since they are heavier and carry less charge than other battery types.

Choosing a Laptop Charger

Laptop chargers can be sold for specific brands and models of laptops, or they can be universal. Universal adapters come with a set of 6 or 7 tips that connect to the laptop, and with a few voltage settings. These are especially useful when one has several laptops and wants an adapter that works with all of them. The main specifications to look at when choosing a charger for a laptop are the voltage requirements (input and output) and the tip connection size. This information can usually be found in the laptop manual. One should also know the model number of the old charger. This number is printed on the back of the charger.

How to Buy Batteries and Chargers

The best time to buy a UPS, batteries, or charger for your laptop or desktop computer, is before the power goes out and these items are desperately needed. Buying these accessories in the middle of a power crisis can result in rushed purchases that may or may not work properly. Instead, you can find all the necessary accessories on eBay from the convenience of your home, and relax knowing that your powering needs are covered in case of a blackout.

To find UPS units, laptop batteries, or laptop chargers on eBay, simply enter the appropriate search term in the search box on any eBay page. You can then refine the search by choosing the appropriate subcategory, or by choosing from the search criteria provided. For example, entering a maximum and a minimum price when shopping on eBay allows you to see just the specific items that fit into your budget. This is a great way to avoid overspending.

Choosing a reputable seller on eBay is as easy as looking at the seller's feedback score. For detailed information on a seller's feedback, click the seller's name and browse through his or her feedback history. eBay's feedback system provides a high level of security for both buyers and sellers.


Power solutions for desktop and laptop computers are essential to smooth operation of the system. The lack of a back-up battery can mean disaster if the power suddenly goes out. Dips and surges in the mains power supply can adversely affect electronic equipment over time as well. An Uninterruptible Power Supply, or UPS, can prevent both of those problems in the home as well as in the workplace. Different types of UPS systems are available to make sure a power outage does not mean a loss of work and information.

Laptops also need a conditioned power supply, but more importantly, they need a functioning battery and charger. As both batteries and power adapters tend to fail every couple of years, it is a good idea to be prepared in case either source happens to run out of power. A third-party battery or adapter can often do the job for a fraction of the price of the original parts, but users should know that there are sometimes risks involved with buying cheaper imitations. By learning to shop for batteries, chargers, and other computer powering supplies on eBay, shoppers can get great deals and find parts and models not usually available in stores.