The Compass Battery Module uses high-energy Lithium Thionyl Chloride double-D size batteries in a stack of eight with 150° C (302° F), 165° C (329° F), 180° C (356° F) temperature ratings available.

The cells are diode protected to prevent reverse power charges, and are protected by a 5 Amp fuse on the power line. The battery pack will run an MWD system for over 150 hours at a standard pulse rate with a Tensor Pulser, and 80 hours with a gamma probe added.

With an upgraded Compass Pulser, a battery pack will operate the MWD system for over 450 hours and over 300 hours with an added gamma probe.

Source - https://compass-mwd.com/battery-module/

Compass Directional Services Ltd.