Battery Information

What do the power ratings mAh, Volts, Whr and Watts mean?

Milliamp Hours or mAh represents the amount of stored energy in your battery. The higher the mAh rating the longer a battery will last. Many of our batteries have higher mAh ratings than original brand batteries. These higher mAh batteries are still 100% compatible with your laptop. It just means the higher capacity battery will last longer than the original.

Watts measures the amount of energy a device uses. This rating is commonly found on your monitor, laptop or other devices that pulls energy from a battery source. Watt Hour or Whr is the amount of power used over a period of time (1 hour). 1 Whr is equal to 1 Watt of power used for an hour.

Voltage measures the volume of electricity that is delivered to your laptop. Many laptop makers have produced batteries that have differing voltage ratings. There are no compatibility issues if your laptop and laptop battery have different voltage ratings. We carry both 11 volt and 14 volt versions of the same battery in case you are unsure.

Most laptop chargers are rated at 19 volts. The extra voltage a charger has over a battery is so the charger can simultaneously power the laptop and charge the battery (if they had the same voltage rating the charger would only have enough power to run the laptop).

Cells Voltage / Cell Formula Nominal Voltage
1 cell 3.6V or 3.7V 1 cell x 3.6 or 3.7V 3.6V or 3.7V
2 cells 3.6V or 3.7V 2 cells x 3.6V or 3.7V 7.2V or 7.4V
3 cells 3.6V or 3.7V 3 cells x 3.6V or 3.7V 10.8V or 11.1V
4 cells 3.6V or 3.7V 4 cells x 3.6V or 3.7V 14.4V or 14.8

Can You Revive a Dead Laptop Battery?

The simple answer is no. Just like a car battery, your laptop battery is a component that is guaranteed to wear out over time. If your laptop battery is not working after charging or is more than 2 years old it may have already experienced its life of 300-500 recharges.

Do not try to disassemble the laptop battery or try the DIY methods listed out there. If your laptop battery is less than 2 years old but doesn’t hold a charge as long as it used to, you can calibrate your laptop battery to regain the full power capacity.

If your laptop does not power on even while plugged into the wall charger, you may need to replace your AC Adapter. There may also be other issues with your laptop, such as a faulty power connector or fried motherboard. 

Should I buy a used Laptop Battery?

We at do not recommend or sell used laptop batteries. Buying a used laptop battery is like buying a used car battery and won’t improve battery time much more than your current one. The life of a rechargeable laptop battery is about 300 to 500 charge and recharge cycles, or about 3 years. A used laptop battery may not be any better than the non-functioning one you are currently seeking to replace. And compared to the cost of a brand new replacement laptop battery they are not a bargain. 

How can I extend my laptop battery run time?

Your new laptop battery will have an average run time of 1 1/2 hours to 3 1/2 hours depending on what applications you are running. Functions that require more power will deplete your battery faster. You can extend your battery run time by minimizing the main power draws on your battery – the LCD brightness levels and the use of your CD or DVD drive. Also, some notebooks simply use more power than others. 

You can prolong your laptop battery life by adjusting the power management selections within your operating system software. If you are a Windows user, you can go to the control Panel and select power options. In this area you can choose when and how you can maximize your laptop battery settings.

How can I minimize the power my laptop uses?

Your laptop battery life depends on the power capacity of your laptop battery and the amount of energy your computer draws. You can maximize your laptop battery life by changing the amount of power your computer draws while in battery mode. 

Tips to Reduce Power Usage and Maximize Laptop Battery Run Time:

-Reduce the brightness of your laptop screen. The screen is the biggest battery drain.
-Avoid using the CD or DVD drive as the motor consumes a fair amount of power. 
-Turn off your wifi finder if you’re not connected to the internet.
-Remove any devices plugged into your USB ports or other ports. 
-Close unused programs or apps

If you are a Windows OS user, within the Control Panel section you will find Power Options. In this section you can change power use and low power alerts. Windows users will also be able to lower the brightness of the LCD panel and extend the battery life considerably. You can also extend your battery life between charges by minimizing the use of your CD and DVD drive operation.

If you are a Mac OS user, within the System Preferences go to the Energy Saver to access the battery and power adapter settings. You will be able to adjust graphics, screen, disk and sleep settings that improve battery usage and laptop performance.

What is the difference between lithium, lithium-ion, NiCad and NiMH batteries?
Lithium and lithium-ion batteries are often confused with the older NiCad batteries found in power tools and other household items. With NiCad batteries you had to run the battery all the way until it was dead. Lithium-ion batteries use superior technology that allow for multiple (shallow) recharges and should not be run all the way empty. 

What is the difference between Lithium and Lithium-ion batteries?

The main difference between lithium and lithium-ion batteries is that lithium-ion batteries are rechargeable. Lithium batteries use lithium in its pure chemical form whereas lithium-ion batteries use lithium compounds

What is the difference between Lithium-Ion batteries and NiCad or NiMH batteries:Lithium-Ion (Li-Ion) has become the new standard for portable power in consumer devices and laptop batteries. Li-Ion batteries produce the same energy as NiMH battery but weigh approximately 20%-35% less. This can make a noticeable difference in devices such as cellular phones, camcorders or notebook computers where the battery makes up a significant portion of the total weight. Another reason Li-Ion batteries have become so popular is that they do not suffer from the “memory effect” at all. They are also environmentally friendly because they don’t contain toxic materials such as Cadmium or Mercury.

What is the difference between NiCad batteries and NiMH batteries?

NiCad (nickel Cadmium) batteries are best known as the battery type that has the memory effect. In order for these batteries to work efficiently, the battery must be completely discharged before recharging. If you recharge these batteries while there is still power stored in the cells, your battery will reset itself so that it now only holds the amount of power stored from the last recharge. Many electric tooth brushes, power tools and other consumer items still utilize NiCad battery chemistry. If you have devices with NiCad batteries, you will save yourself some aggravation and money by having a fully charged spare battery to insert while you recharge your depleted battery. NiCad batteries are the least expensive to produce, but because of the memory effect problem, these type of batteries are slowly being phased out with other improved battery materials.NiMH batteries are less prone to develop this problem and thus require less maintenance and conditioning. In addition, NiMH batteries can store about twice as much energy as NiCad batteries without adding any additional weight. NiMH batteries are also environmentally friendlier than NiCad batteries since they do not contain heavy metals (which present serious landfill problems). Note: Not all devices can accept both NiCad and NiMH batteries.

How to Calculate Laptop Battery Run Time

You can calculate your laptop battery life by dividing the battery capacity (Watt-hours or Whr) from the power consumption of your laptop (watts).

Calculate Battery Life 
Watt Hours / Watts = Battery Life (in hours)

Example: 60 Whr / 20 Watts = 3 Hours

Laptop Battery Life Calculator 
Enter the Watt Hours and Watts to calculate your battery life in hours. If you don’t know the Watts or Watt-Hours, use the formulas below.


Calculate Watt-Hours
Whr= Volts x mAh / 1000

Example: 14.8 Volts x 4060mAh / 1000 = 60.09 Watt-Hours (rounded up) 

Calculate Milli-Amp Hours 
mAh = Whr x 1000 / Volts

Example: 60.09 x 1000 / 14.8 = 4060 mAH (rounded down)

How to Extend the Life of your Laptop Battery

Prolong the life of your battery by using it more!When your laptop is plugged into the wall it runs on it’s primary power source, the power cord. Lithium-ion laptop batteries go into standby mode when they are plugged in. Exercise your battery by letting it go unplugged at least once a week. Keeping your laptop plugged-in all the time the battery will become out-of-shape, giving you shorter run-times and lower performance. This is the most common reason lithium-ion batteries wear out. Of course, never burn, disassemble, mutilate or short-circuit laptop batteries.
Don’t run your battery all the way to 0%The second most common reason why laptop batteries wear-out or fail is that they are frequently discharged all the way to empty. If a laptop battery is run below 3% it can damage the battery and may not be able to operate correctly. 

Research shows that Lithium-ion batteries last longer when they have shallow discharge and recharge cycles. It does not harm the battery to only use it for 5-10 minutes and then plug it back in to the power cord. Rechargeable batteries will self discharge when not in use over a period of time.Fully charge your laptop before first useYour new battery comes in a discharged state for shipping. Recharge your laptop battery at least 5 times so you can get the full capacity of the battery.Recharge your battery before letting it get to 20%Studies show that batteries will last longer when they are recharged at 20% battery life and are charged to 80%. This will maximize the life of your battery.

The average run time for most laptops is 1.5 hours to 4 hours depending on the laptop model and what applications are being used. Laptops with larger screens tend to have a shorter battery run time. 

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