This is a brand new HP ProBook 4421s extended run premium grade replacement battery. The additional cells in this cartridge will protrude to the bottom of the laptop about 1 inch. This will have the effect of raising the rear of the laptop. The superior South Korean cells inside the battery cartridge will provide longer run times between charges as well as a longer service life than cheaper batteries. In addition, Li-ion batteries are not subject to the memory effect common with older fbattery technology. This means you can recharge your HP ProBook 4421s laptop any time without diminishing your battery capacity. This HP ProBook 4421s laptop battery replacement is typically superior to the original battery and is 100% compatible with your HP ProBook 4421s notebook computer. The battery is individually tested before shipment and backed by 30 day complete satisfaction guarantee and a 2 Year warranty.

Check your current battery to ensure you are ordering the correct battery. It should match the picture above. This battery will provide about 3 hours to 4.5 hours of run time with this computer battery when new, depending on your energy use.

This battery replaces the HP ProBook 4421s series laptop batteries and a host more which are listed at the extreme bottom of this web page.

Laptop Battery Express only deals with brand new premium computer batteries. We never carry recycled or used batteries. We only use the highest quality cells inside the battery pack so you will have a long service life (300-500 recharge cycles). We do not use cheaper battery cells which can wear out in a little as 3 to 6 months. Our inventory turns rapidly and you will always receive a freshly manufactured battery.

How to care for your HP ProBook 4421s battery.

You can extend the life of your laptop battery significantly through the proper care and handling of your battery.

• Any new HP ProBook 4421s laptop battery should first be fully charged by leaving it plugged in overnight. Once a computer battery is fully charged it will no longer accept any more power. It is a common practice to leave laptops plugged in after they have been turned off so that the battery has a full charge the next time you use your laptop. It is probably fully charged within 5 hours.
• A brand new notebook battery is in a weakened condition since it has not been conditioned yet. Condition and break in your new battery by performing 5 partial discharge and recharge cycles the first week you receive your new battery.
• Run on battery power without the AC adapter cord at least once a week to keep the battery cells active and at their peak potential. When your laptop is plugged into the power adapter the battery goes to "standby mode" while your laptop runs directly on electricity from the wall outlet.
• Even though your HP ProBook 4421s battery indicates it is fully charged, your battery will return to a weakened state again in a few months if it does not get some exercise through partial discharge and recharge cycles while running on battery power alone.
• If your battery has not been actively used 2 months or more, condition your battery again with 5 partial discharge & recharge cycles to increase the batteries capacity and run time.
• Don't run your battery all the way to empty. Your battery will have a longer service life if it receives shallow discharge and recharge cycles. Research has shown that the useful life of the battery will be much longer if you begin to recharge the battery any time before reaching 20% of the remaining power capacity. Recharging the battery even after 10 minutes will not reduce the battery's life span as lithium batteries do not have the memory effect which was found in older NiCad battery technology. NiCad batteries have never been used in laptops, even the earliest models.
• Never run your battery below the 3% critically low warning point. If your battery is run below this point it may not have enough energy to recharge. This may effectively "kill" your battery.

How can I extend my HP ProBook 4421s battery run time?

You can extend your battery run time by minimizing the power drain on your battery. A 6 cell battery will run approximately 2 to 2-1/2 hours when the battery is new. Even longer times can be achieved by minimizing the power consumption of your laptop. Here are the top ways to reduce your power consumption.

• Reduce the brightness of your laptop screen. This is the main drain on your HP ProBook 4421s battery by far.
• Avoid using the CD or DVD drive as the motor consumes a fair amount of power.
• Turn off your wireless finder if you are not using the internet.
• Remove any devices plugged into your USB ports or other ports.
• Close out programs you are not using. By minimizing the load on your CPU, sometimes you can avoid having the cooling fan turn to its high speed mode.
• Increase your memory to at least 4 Gigabytes. This creates less work for your hard drive. Data is temporarily written to your hard drive when your memory is not sufficient to hold all the data on the many pages you may be accessing.