Knowledge Base

Laptop Battery FAQ

This article has information to common questions about laptop batteries including how to choose the best battery for you; battery life and how to make your battery last longer between charges; how to install and charge your battery, and much more

Note: Like most laptops, Dell laptops use lithium ion batteries, which can swell for a variety of reasons such as age, number of charge cycles, or exposure to high heat. While a swollen pack does not represent a safety concern, damaged or swollen components should not be used. Should you have an issue with a battery pack swelling, we recommend discontinuing use and replacing it with a Dell authorized battery.

Note : Please click on the title of the section you want to open below, in order to see the contents.

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All rechargeable batteries wear out with time and usage. As time and cumulative use increase, the performance will degrade. For the typical user, noticeable reduction in run time generally will be observed after 18 to 24 months. For a power user, reduction in run time generally may be experienced prior to 18 months. We recommend buying a new Dell laptop battery when the run time does not meet your needs.
Information on Extending the Life of your Battery.

A Higher Watt hours (Whr) on the same system under the same operating conditions will generally deliver longer battery run time. For example, if you compare the same system, running the same applications, the 53Whr battery would provide approximately 65% more run time than the 32Whr battery.

When choosing a battery, the main quality that you need to consider is the amount of energy that can be stored in a battery. This is measured in Watt- Hours (Whr). For longer runtime per charge, choose a battery with a greater Whr rating

If you want Choose Trade off
Longer runtime Higher Capacity Higher cost
Heavier weight
Lighter weight Lower Capacity Lower runtime
Lower cost Lower Capacity Lower runtime

Note: When used under the same conditions, a lower capacity battery will wear out faster than a higher capacity battery because it has to be charged more often.

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The battery charges in the laptop when the laptop is connected to an AC power source via the AC adapter. The charge time varies depending on the system. If the system supports ExpressChargeT™ , the battery typically will have greater than 80% charge after about an hour of charging, and fully charge in about 2 hours with the system off.

For a system advertised as having the ExpressCharge™ feature, the battery typically will have greater than 80% charge after about an hour of charging and fully charge in about 2 hours with the system off.

No, the battery is designed to stop using the charger when it reaches full charge.


Is it easy to install a battery? Yes, very easy. First, make sure all open files are saved. Be sure to remove the Ac Adapter and that the computer is off before trying to install or replace a battery.

Click here for your Service Manual for instructions on how to replace your battery.

Dell has a rigorous qualification process by which all Dell batteries are validated to ensure proper function, performance and safety. Some non-Dell batteries are available in the market with claims of compatibility with Dell systems. Dell cannot verify these claims, nor the safety of using them in a Dell system. Dell strongly encourages our customers to use only Dell laptop batteries advertised as appropriate for their laptop model. Only Dell laptop batteries come with a 1-year warranty, are engineered for optimal safety and performance for Dell systems, and are supported by Dell technical support for the length of the warranty period.

In some laptop systems Dell offers a battery that can be used in the optical drive media bay (DVD/CD drive bay). This enables the use of two batteries, potentially extending the available run time.

If I install a modular bay battery, are my primary and modular bay batteries working at the same time to power my laptop computer?

No, the modular bay battery is used first, then the system automatically switches to the primary battery. This is a deliberate design to allow the most amount of run time to remain in the primary battery in case the modular bay battery is removed and replaced with an optical drive.

Note: For Latitude Exx20/30 models (eg. E6420 or E6430) the primary battery is drained before the modular battery is used.

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Most Dell batteries have an LED indicator that allows users to see how much run time and how much overall battery life are available at the touch of a button. To check battery charge, press the button and the number of lights that appear will tell you charge status. If all lights appear, you have a fully charged battery. Each light that appears accounts for approximately 20% charge. To check the battery health, press and hold the status button on the battery charge gauge for at least 3 seconds. If no lights appear, the battery is in good condition and approximately more than 80 percent of its original charge capacity remains. Each light represents incremental degradation. If five lights appear, approximately less than 60 percent of the charge capacity remains, and you should consider replacing the battery. You can find out more about this in the guide linked below :

When storing for more than 4 days these guidelines can better preserve the life of your battery :

  • Do not store batteries for long periods plugged into or attached to any power source. This includes AC adapters and laptop security carts plugged into an outlet.
  • Laptop batteries, including those stored in laptop systems, should maintain an Operational Storage Temperature of 0° to 35°C (32° to 95°F).
  • Batteries may be stored in the laptop or outside of the laptop.
  • Charge batteries before storing. The recommended charging time should not exceed 1 hour. Typically, this should charge the battery to between 80% and 100%. (Some discharge will take place over time. Stored batteries are expected to discharge 10-15% over a four month period, for your information.)

Some Dell laptops have a battery that attaches to the bottom of the system, providing additional runtime for the laptop.

There are several things you can do to make your battery last longer :

  • Choose the right battery. Under the same use conditions, a lower capacity battery will wear out faster than a higher capacity battery because it has to be charged more often.
  • Use the notebook's power saving controls to reduce battery use in your normal day. For example, turn the Bluetooth off if it is not needed; reduce the screen brightness when conditions permit.
  • Avoid exposure to extreme temperatures. If the system is exposed to extreme cold or hot temperatures, allow it to warm up/cool down before use and before charging.
  • Contrary to last decades' batteries, modern lithium ion batteries do not need to be fully discharged to maintain health.
  • All batteries wear with use and time. When you find the runtime is no longer satisfactory, it may be time to purchase a new Dell battery.

No, with current lithium ion batteries this practice does not improve the runtime of the battery. This practice is a holdover from the days in which NiMH batteries were used.

While not required, it is recommended to fully charge your battery.

No, the battery has built in controls which stop the charging process when the battery is full.

Dell advises you to check the health of your battery regularly. Battery life will decline over time. Batteries are a consumable item. Follow the Guide linked below to see the current status of your systems battery health :

The quick answer to this is that it depends on the age of your system. Older systems do not have the capability to test the battery in the PSA diagnostics. However since the Enhanced PSA diagnostics were introduced on the Latitude E3 systems, the diagnostics have included tests for the battery. To find out more about this subject please check out the guide linked below :

Dell considers Batteries to be a consumable item, because All batteries degrade with time and use. The warranty is very similar to common auto warranties which exclude consumable items such as tires. Dell supplies separate warranties on it's batteries and you can check up on this using the guide linked below :

Dell's standard battery warranty is one year. Batteries are a consumable item. All batteries degrade with time and use. The warranty is very similar to common auto warranties which exclude consumable items such as tires. For copy of Ltd Hardware Warranty, write Dell USA LP, Attn: Warranties, One Dell Way, Round Rock, TX 78682 or see .

To find the MSDS for a specific battery, refer to the Product Safety, EMC and Environmental Datasheet published within the drop-down menus at this website.

If you are seeking a Materials Safety Datasheet for a product(s) which is no longer available for purchase, e-mail mailbox with the laptop computer name and the battery part number for the relevant product(s) included in the body of the e-mail.

Battery Charge Reporting in Windows

When the battery charge is fully charged to 100%, the Charge Field Effect Transistor (FET) will stop charging the battery. Afterwards, the battery will naturally discharge during use. When the battery charge drops to 95%, the Charge FET will begin to apply a trickle charge to the battery and again charge the battery to 100%. This is working as designed and is intended to extend the physical life of the battery.

Battery Charge Reporting in System Setup

If you enter the System Setup utility (BIOS), the battery charge should be reported at 100%. If it is not, charge the battery until it reaches 100% in the BIOS.

Note: For information on entering the System Setup (BIOS), refer to Dell Knowledge Base Article: "What the BIOS Is and How to Access it on a Dell Computer " Article ID: sln129956.

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If a laptop is stored for an extended period of time with the battery in the system, the battery may not charge as expected when AC power is applied. The battery indicator LED may signal a fast flashing 4 Amber, followed by single steady Blue (or Green depending on the system) pattern (Figure 1). This pattern signifies a ‘Temporary failure’ of the battery. On older laptops, the system battery indicator LED may not illuminate, and it just does not charge the battery. The cells within the battery packs trickle discharge over time but the firmware of the battery pack still think it is fully charged. The cells eventually reach a level of close to zero charge, and the battery's firmware is still thinking it is fully charged. When powered on with the system, it performs an integrity check and it generates an error as there is a mismatch between the firmware's indicated power level and the actual cell charge.

Figure 1 : Temporary Battery Failure Indication

Solution : The following procedure may recover the battery pack :

  1. Physically remove the battery pack from the system and leave it out for 1 minute, which allows sufficient time for the batteries firmware to resynchronize with the actual cell charge state.

  2. Insert the battery into the system at this point, and leave it on charge for an extended period of time. Approximately 12 hours will be sufficient to recover the battery pack to its peak performance.

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battery and power support Visit our Battery and Power site for additional resources and information.

Article ID: SLN128667

Last Date Modified: 04/13/2018 03:34 AM

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