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Black rectangular lithium-ion laptop battery with label showing 11.4V 42Wh

GOLDIX

GOLDIX WY9DX 42Wh 11.4V laptop battery for Dell Latitude 5420 5520

SKU CH-RJ53-X768F

42 Wh 11.4 V lithium-ion replacement battery for Dell Latitude 5420 and 5520 series

  • Battery typeLithium-Ion
  • Battery voltage rating11.4 V
  • Battery capacity42 Wh
  • Product colorBlack
  • Product typeBattery
  • Compatible withFor Latitude 5420 5520 Series
  • 42Wh capacity powers Dell Latitude 5420 and 5520
  • 4V lithium-ion cell matches original voltage spec
  • Replaces WY9DX RJ40G 005R42 31CP5/57/78 part numbers
  • Brand new condition ready for immediate installation
  • 12 month coverage included with purchase

GOLDIX WY9DX 42Wh battery for Dell Latitude 5420

This replacement battery supplies 42Wh at 11.4V using lithium-ion cells in a black housing. It fits Dell Latitude 5420 and 5520 series laptops and replaces part numbers WY9DX, RJ40G, 005R42 and 31CP5/57/78.

Lithium-ion chemistry and 11.4V nominal voltage

Lithium-ion cells degrade over time and lose capacity after repeated charge cycles. The 11.4V rating must match the original specification exactly or the laptop will not recognise the pack. No higher-capacity alternative is offered in this form factor.

Direct swap installation with screw access

The pack installs by removing the bottom case screws and disconnecting the old cable. Common issues include forgetting to detach the connector before prying the pack loose and stripping the small case screws during reassembly.

How it compares

Measured against everything we stock in Laptop Chargers & Batteries, at today’s prices. Recalculated every night.

Price $34.99
Pricier than about 62% of the 27,790 comparable items (median $30.99).

Specifications

Product
Brand nameWY9DX
Model nameWY9DX
Part number31CP5/57/78
Product colorBlack
Product typeBattery
Power
Battery typeLithium-Ion
Battery voltage rating11.4 V
Battery capacity42 Wh
Compatibility
Compatible withFor Latitude 5420 5520 Series

Questions about this item

How do I know the 42Wh 11.4V version is the right one for my Latitude 5420 or 5520?

Match the original part numbers — this battery replaces WY9DX, RJ40G, 005R42 and 31CP5/57/78, all listed for the Latitude 5420 5520 series.

What does the 42Wh rating actually give me in daily use on a Latitude 5420?

The 42Wh capacity at 11.4V is the factory-spec energy rating for these models, so runtime will match the original battery when new.

Does the battery use a standard Dell interface and will it charge to 100 % in the laptop?

Yes — it is built to the same 11.4V Li-ion specification and fits the Latitude 5420 5520 charging circuit, so it charges normally.

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