Dell Latitude D420 JG917 Replacement Battery 11.1V 5800mAh

Dell Latitude D420 / D430 — 11.1V Li-ion Replacement Battery (JG917)

This is an 11.1V, 5800mAh (64.38Wh) lithium-ion battery for the Dell Latitude D420 and D430 ultraportable notebooks. It replaces OEM part numbers JG917, JG176, KG126, KG046, 451-10365, and several others in that cross-reference group. The connector and BMS pinout match the original Dell battery slot directly.

• D420 and D430 platform compatibility: Both models share the same battery bay dimensions, connector pinout, and SMBus communication protocol. The BMS in this cell speaks the same handshake the EC firmware expects, so the system accepts it without throwing an unknown device warning on first boot.
• Bench tested on actual hardware: We ran this cell on a D420 unit through a full charge-discharge cycle. The BMS held the charge termination voltage at 12.6V, protection kicked in correctly at low-cell cutoff, and the SMBus reported accurate state-of-charge data back to Windows throughout.
• First-cycle calibration on the D420: After installation, run one full discharge to hibernate cutoff, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell chemistry and clears the inaccurate "poor health" warning that appears after every cell swap on this platform.

BIOS reporting battery health as poor immediately after replacement

The D420 BIOS stores learned capacity data in EEPROM tied to the previous cell's cycle history. When a new cell goes in, that stored data no longer matches actual cell behaviour, so the BIOS flags health as degraded. This is not a fault with the replacement battery. Run one complete discharge-to-hibernate followed by an uninterrupted charge to 100% — the learn cycle overwrites the stale EEPROM values. After two or three calibration cycles the health indicator returns to normal.

Laptop shuts down at 20–30% shown on the fuel gauge

The fuel gauge IC on the D420 estimates remaining capacity using a model built against the old cell's internal resistance curve. A new cell has a different resistance profile, so the gauge loses accuracy under load — it reads 25% while the cell is actually near cutoff voltage. The laptop shuts down not because the battery is faulty but because the voltage drops below the EC's threshold before the gauge catches up. Run two to three full discharge-and-charge calibration cycles and the fuel gauge IC will re-map its model against the new cell. After calibration, shutdowns at falsely high percentages stop occurring.