Simple Guidelines when Repairing HP 740715-001 Battery Packs

Only connect cells that are matched in capacity. Do not mix cells of different chemistries.
Never charge or discharge Li-ion batteries unattended without a working protection circuit. Each cell must be monitored individually with a protection circuit.
Include a temperature sensor that disrupts the charge current on high heat.
Apply a slow charge to a repaired pack to bring all cells to parity.
Pay attention when using an unknown brand. Elevated temperature hints to an anomaly.
Li-ion is sensitive to reverse polarization. Observe correct polarity.
Do not charge a Li-ion battery that has physical damage, has bulged or has dwelled at a voltage of less than 1.5V/cell for some time.
Check a repaired pack for self-discharge. Intrinsic defects often have high self-discharge.

Source from http://batteryuniversity.com

HP 740715-001 Battery 

HP 740715-001 Battery 

Brand new HP 740715-001 14.8V 2620mAh laptop batteries

Voltage: 14.8V

Capacity: 2620mAh (41Wh)

Battery cells: 4-cell

Chemical: Li-ion

Battery Color: black

Condition: new original battery

Warranty: 9 months

Product link: http://www.storebattery.co.nz/hp-740715-001-14.8v-2620mah-laptop-battery-store-for-new-zealand-p-126045.html