HP guide description: "3-cell, 24-WHr, 2.4-AHr". OEM documentation only; not bench-tested.
Source notes
HP EliteBook 840 G2 Notebook PC / HP EliteBook 740 G2 Notebook PC / HP ZBook 14 G2 Mobile Workstation Maintenance and Service Guide, printed p40 (PDF p50): "3-cell, 24-WHr, 2.4-AHr 717375-001".