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Manufacturer: Dell Last updated: 2026-09-29
Dell RJ40G Replacement Battery Review
Dell RJ40G replacement battery, the 63Wh 4-cell 15.2V pack for the Dell Latitude 5420, Latitude 5520 and Precision 3560.
Dell's Latitude 5420 spec sheet lists this 4-cell 63Wh pack as the larger of two battery options, at 238 mm long versus 207.9 mm for the 3-cell 42Wh pack (Dell WY9DX). Parts-People sells it as the Dell OEM RJ40G and lists M033W, 1K2CF and 75X16 as older codes for the same part.
Our verdict
Reviewed by Burooj Alam. Rated by us, not by users.
Best for
- Latitude 5420 and 5520 owners who want the longer-running battery
Not for
- Latitude 5420 units built for the 3-cell 42Wh battery, unless you confirm the larger pack fits
Specifications
What these specs mean| Brand | Dell |
|---|---|
| Battery Model Code | RJ40G |
| OEM Spare Part Number | RJ40G, 0RJ40G |
| Nominal Voltage | 15.2 V |
| Cell Count | 4 |
| Series Configuration | 4S |
| Capacity Wh | 63 Wh |
| Capacity Basis | OEM Label |
| Length | 238 mm |
| Width | 95.9 mm |
| Thickness | 5.7 mm |
| Compatible Models | Dell Latitude 5420, Latitude 5520, Precision 3560 |
| Replaces Part Numbers | M033W, 1K2CF, 75X16 |