Tips to help you to to get your samsung NP940X3N battery work longer

It's normal for your battery to not charge more than 97 percent when powered on. This prevents overcharging and prolongs the life of the battery. However, if your battery just isn't lasting as long as it should, you may need need to perform a battery calibration.

Close any programs that are in use.
Save any work you may be doing, and then close all running programs or applications.

Disconnect the AC Adapter.
Smart Battery Calibration will not run when the AC adapter is connected.

Restart and run Samsung BIOS configuration.
Restart the PC, and then press F2 when the SAMSUNG logo appears. This will start the Samsung BIOS Configuration.

Run the Smart Battery Calibration.
Click Advanced on the left-side menu, and then double-click on Smart Battery Calibration on the right-side menu. The battery will be discharged by the PC. The process may take up to 5 hours depending on the capacity and remaining battery life. To cancel the operation, press the ESC key.

Charge the battery.
After the battery has been completely discharged, connect the AC adapter to your PC and charge the battery. You can use the PC while the battery charges, or leave it off until fully charged.

Source from https://www.samsung.com/us/support/search/?searchTerm=Series 9 Notebook NP940X3N&page=1&sort=relevance&SiteType=support&SupportTopics=Power %26 Battery&ModelCode=N0052760

Here is the brand new samsung NP940X3N laptop battery detail we have for now, it is brand new, and it should be allowed to replace with part number AA-PBTN4LR. 

Price: 105 USD

Voltage: 15.4V

Capacity: 3530mAh (54Wh)

Battery cells: 2-cell

Chemical: Li-ion

Battery Color: white

Condition: new original battery

Warranty: 9 months

The battery is available here: https://www.storebattery.co.nz/samsung-aa-pbtn4lr-15.4v-3530mah-laptop-battery-store-for-new-zealand-p-210242.html