Instructions of removing the DELL Precision 5520 battery

Last time we shared how to install a new DELL Precision 5520 battery, today we'd like to share how to remove a battery. This instruction is from https://www.dell.com, so this would be the correct instruction, no doubt.

NOTE: Discharge the DELL batteries as much as possible before removing from the system. This can be done by disconnecting the DELL AC adapter from the system (while the system is turned on) to allow the system to drain the DELL Precision 5520 battery.
Follow the procedures in Before Working Inside Your Computer .
Remove the Base cover
Perform the following steps to remove the DELL Precision 5520 battery:
Disconnect the DELL Precision 5520 battery cable from the system board .
Remove the seven M2x4 screws that secure the DELL Precision 5520 battery to the computer .
Lift the battery off the computer .
Do not apply pressure to the surface of the battery
Do not bend
Do not use tools of any kind to pry on or against the DELL Precision 5520 battery.

DELL Precision 5520 battery

DELL Precision 5520 battery

Brand new DELL Precision 5520 11.4V 4649mAh laptop batteries

Voltage: 11.4V

Capacity: 4649mAh (56Wh)

Battery cells: 3-cell

Chemical: Li-ion

Battery Color: Black

Condition: new original battery

Warranty: 9 months

DELL Alienware 17 R2 14.8V 6200mAh laptop battery original battery

DELL Alienware 17 R2 14.8V 6200mAh laptop battery

Original Battery DELL Alienware 17 R2 Series Battery Detail：

Price:N$187.40 Save: 29% off (Including taxes)
Voltage: 14.8V
Capacity: 6200mAh (92Wh)
Battery cells: 8-cell
Chemical: Li-ion
Battery Color: black
Condition: new original battery
Warranty: 9 months
Status: In stock
Tested before shipping: Yes

Compatible with following DELL laptop model: 
DELL ALW17ED-1828T,DELL ALW17ED-3728,DELL ALW17ED-1728,DELL  ALW17ED-4838, DELL ALW17ER-4838, DELL ALW17ED-3828, DELL ALW17ED-4738,DELL ALW17ER-4738, DELL ALW17ED-2728, DELL ALW17ED-4718, DELL Alienware 17 R3,  

Compatible with following DELL battery model number:
DELL 6JHDV, DELL 6JHCY  

Factors Affecting Battery Life

As batteries age they gradually lose their capacity as their function is performed. The constant charge and discharge eventually leads to failure. Components corrode over time, electrical shorts occur and vibration causes damage; all eventually causing failure. Overcharging and undercharging of a battery will also have a bearing on battery life.
Battery Inspection

Check electrolyte level - fluid below the tops of the separators indicates overcharging or poor maintenance. Overcharge condition may be due to incorrect voltage setting, low voltage caused by heat or internal defects, or old age deterioration.

Is there electrolyte on the top of the battery? This can indicate overcharging or overfilling.

Is the battery loose in the carrier? This can cause failure from vibration.

Does the battery have signs of damage or mistreatment? This can also cause failure.
Discharged (flat) Batteries

A flat battery should be checked with a hydrometer. A low Specific Gravity reading of 1.220 or less in all cells indicates a discharged battery and it must be charged before further examination and testing can occur. The discharged condition may be due to a problem in the electrical system (slipping alternator belt, faulty regulator or alternator, high resistance due to corrosion). Internal shorts may also be due to manufacturing defects or shorts through the ageing process or vibration damage.
Early Warning Signs

Batteries often fail when least expected. The usual warning is a slower than normal battery ability to crank the engine. Other less noticeable factors, such as changed driving patterns and colder/hotter weather will all have an effect on the life of a battery. Encourage your customers to ask for a ‘FREE Battery Test’. It’s good public relations and if the battery is near failure, it may avoid the inconvenience of a roadside breakdown.