Dell Latitude 5590 Battery Replacement

Introduction

This is the battery model GJKNX, the 68 watt hour battery. This also applies to the other capacities as well, this one being the biggest.

Turn the laptop onto its back, screen facing down onto a protected surface to avoid scratching
Using a Philips 1 bit, unscrew the 8 screws that hold down the cover. They are captive, so they will not fall out
Carefully pry off the back, starting from the back until it comes off completely

After removing the back cover, locate the battery connector and single screw. The screw will be to the far right of the battery, right next to the outer chassis
Remove the screw, and disconnect the battery by carefully pulling the connector's fold out strap. If it is difficult to remove, insert a thin rod and use your hand force to pull it off carefully

Lift up the battery from the motherboard side. It comes out at an angle.
The new battery may not include a cable. If it does not, then carefully remove the cable from the battery that was just removed, and connect it to the new one. It can be connected only one way, do not force it in.

Insert the new battery, ensuring that it is inserted at the same angle used to remove it, inserting the bottom first, then the top that is closest to the motherboard
Reroute the cable, and ensure that it is not sharply bent
Reconnect the battery, and reinstall the screw. If the new battery has no screw, then the old one can likely be reused.

After screwing the battery down and routing the cable, clip the back cover to the system, then refasten all 8 screws
If the battery manual says to do a break in period, then proceed to breaking it in.
To check the battery, enter the BIOS and check. Press F12 before boot, and it will show a startup interrupt screen. Use the arrow keys to navigate to BIOS Setup. Press enter, then go to Battery Information and verify that the system detects the new battery