This is a brand new HP Business NoteBook nx8420 replacement battery. There are two key components inside your battery pack to look for when buying a new computer battery. The quality of the battery’s lithium-ion cells and the quality of the computer chip set in the battery pack. This battery is built with the best components, not the cheapest.
This battery contains the very best Li-ion cells on the market from Samsung. An important specification to look for with rechargeable batteries is the mAh (mili amp hour) rating or Whr (Watt Hour). This battery is rated at 5200 mAh or 58 Whr. This is the highest rating available for a 6 cell battery pack. The higher the mAh rating, the longer your battery will run before it needs to be recharged again. There are no compatibility issues if your existing battery is rated at 4400 or 4800 mAh or a lower Whr. Simply put, more is better. And yes, this battery is probably better than your original!
The other key component inside the battery pack is the computer chip set that contains the program interface with your laptop’s battery meter software and important safety features that monitors when to charge and stop charging your battery. We use Texas Instruments top notch components for this.
When choosing a laptop battery, cheaper is not better. Cheaper batteries use inferior Chinese cells that typically wear out in just 3 to 6 months.  The main indicators of inferior Chinese cells are the low price of the battery and a lower mAh rating. Inferior batteries also use inferior computer chip sets inside that can lead to compatibility issues with your laptop. Although every brand of laptop battery is hand assembled in China, the key to getting a great battery is knowing what components are inside.
Laptop Battery Express is a US based business with knowledgeable support staff to assist you before and after the sale. Yes, we have a phone number and real people answer your call! Free technical support is available if you need additional help in diagnosing power problems with your battery, ac power adapter or battery meter software.
All our products carry a full 2 Year warranty and every battery is charged and tested before it ships.
We provide a 30 day money back guarantee if you are not completely satisfied. We are so confident in the quality of our batteries, we will pay for any and all shipping expenses if our product fails to perform in the first 30 days you have our battery, even if it is not our fault. (PS- if your laptop will not turn on at all when plugged –in, you need a new ac power adapter found at the bottom of this page) Feel free to call for tech support.

You can expect about 2 - 3 hours of run time with this computer battery when new, depending on your energy use. The higher capacity battery cells inside this cartridge have an energy capacity of 5200 mAh. This battery will be compatible with batteries rated at 4400 & 4800 mAh capacities while providing up to 20% more run time.

This battery replaces the HP-Compaq Business NoteBook nc8200 nc8230 nc8430 8510p 8710p nw8200 nw9440 nx9420 NW8240 NW8440 NX7300 NX7400 NX8220 NX8410 NX8420 8510w 8710w 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 Business NoteBook nx8420 battery.

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

• Any new 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 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 Business NoteBook nx8420 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 Business NoteBook nx8420 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.