GOLDIX
GOLDIX WY9DX 42Wh 11.4V laptop battery for Dell Latitude 5420 5520
42 Wh 11.4 V lithium-ion replacement battery for Dell Latitude 5420 and 5520 series
- ColorBlack
- TypeBattery
- Compatibilityfor Latitude 5420 5520 Series
- Battery TypeLithium-Ion
- Battery Voltage11.4V
- Battery Capacity42Wh
- 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.
Highlights
- 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
Specifications
| Brand | WY9DX |
|---|---|
| Model | WY9DX |
| Part Number | 31CP5/57/78 |
| Color | Black |
| Type | Battery |
| Compatibility | for Latitude 5420 5520 Series |
| Battery Type | Lithium-Ion |
| Battery Voltage | 11.4V |
| Battery Capacity | 42Wh |
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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