Which RTC battery fits the HP ProBook 640 G4? OEM part numbers

2 RTC batteries are documented for the HP ProBook 640 G4: 857798-001, L23943-001. 2 of 2 come from OEM documentation (partsurfer.hp.com); last checked 2026-10-23. Not bench-tested: match the number on your old RTC battery and any constraint before ordering.

Part number	Part	Constraints	Confidence	Last checked
857798-001	HP RTC (CMOS) battery 857798-001	Listed for 1 of 8 checked HP ProBook 640 G4 product numbers (4LU94US), so it is configuration-specific. HP description: "ASSY, RTC BATTERY". Confirm your product number on HP PartSurfer before ordering. OEM parts list only; not bench-tested.	OEM documented	2026-10-23
L23943-001	HP RTC (CMOS) battery L23943-001	Listed for 7 of 8 checked HP ProBook 640 G4 product numbers (4FY94US, 4LK98US, 4RH61US, 4FT98US, 4PA87US, 5XC03US, 5LH83US), so it is configuration-specific. HP description: "SPS-RTC BATTERY". Confirm your product number on HP PartSurfer before ordering. OEM parts list only; not bench-tested.	OEM documented	2026-10-23

Where do these HP ProBook 640 G4 RTC battery part numbers come from?

2 of 2 fits are from OEM documentation (partsurfer.hp.com); each row links its source. Last checked 2026-10-23.

Are these RTC batteries tested in the HP ProBook 640 G4?

No. Fits come from manufacturer or retailer documentation and are not bench-tested. Check the part number on your old part and any listed constraint.

All documented parts for the HP ProBook 640 G4.

Other parts for the HP ProBook 640 G4

Power Adapter (5) · Battery (1) · Display Bezel (2) · Cosmetic Plate (3) · Fingerprint Reader (2) · Display Cable (3) · Palmrest (2) · Screen (6) · Display Back Cover (2) · Bottom Cover (2) · Fan (1) · Heat Sink (2) · Hinge (2) · Keyboard (7) · Speakers (1) · Touchpad (4) · Camera (1) · Wireless Card (7) · Card Reader (1) · Microphone (1) · I/O Board (1) · SSD (8) · Power Cord (35) · Cable (1) · Power Button (1) · Motherboard (10) · Service Part (4) · Memory (3) · Antenna (1) · Hard Drive (5) · Screw Kit (1)

For AI agents: the same list as JSON from the free MCP server at /mcp (tool get_model_parts, model hp-probook-640-g4) or the keyless JSON API.