The data conditioning and data storage devices that are used in an MFL tool require power to operate, as well as some sensors. So, the battery power that is available limits the mileage that can be inspected at any time. Most tools use rechargeable battery systems; the capacity of these systems and the energy requirements for the operating systems define the maximum inspection length. The design of the power system must account for the effects of shock and vibration. The system must also meet the size and shape constraints inside the inspection tool.

Several types of standard battery packs are available. Proprietary designs may use nickel cadmium cells, and lead acid cells. These cells are usually connected in series to produce the desired voltage. Encapsulation of the battery units reduces shock and vibration effects. These types of battery packs have been used successfully for years and is considered extremely rugged and reliable. The power capacity of nickel cadmium cells is not as high as some other battery types, but nickel cadmium cells are rechargeable, which reduces inspection costs.

Several types of batteries provide a higher energy level. Various inspection vendors have tested alternative batteries, such as silver-zinc and lithium systems. These batteries provide higher data recording capacities to allow longer inspection distances or they support the use of sensor, conditioning, and storage systems that require more power to operate. Most of these batteries are not rechargeable and require safe disposal methods.