Replace your worn-out battery with a brand new battery for the HP CS03XL battery for the HP EliteBook 745 G3 (generation3) 840 G2 850 G3 and ZBook 15U G3 models.
HP also has these same model names that are G1, G2. These are different laptops and use different batteries.

We use the highest quality lithium-ion battery cell technology in our batteries. The superior Samsung cells and Texas Instruments components last longer, charge faster, and weigh less than cheaper, lower quality batteries.

Each battery is tested, inspected and backed by a full 2 Year warranty. We provide a 30 day money back guarantee if you are not completely satisfied.

You can expect about 2 hours to 4 hours of run time with this HP CS03XL battery when new, depending on your energy use.