Anti-idling regulations have led to increased demand on the batteries’ ability to provide power for accessory equipment on a truck. Auxiliary Power Units (APU) allow drivers to operate hotel loads while the truck isn’t running. These are very convenient but it is important to choose the correct batteries for the application for fleets to get the most return.

The typical role of a battery pack on a heavy-duty vehicle is to start the truck. This means fleets are usually looking at CCAs to determine which battery to purchase. With APU batteries, the CCA rating isn’t what determines if a battery is good for the application. According to Purkeys’ Sales and Service Engineer Charley Gipe, a battery’s reserve capacity is what should be considered when choosing APU batteries.

APU batteries need to supply power for a long amount of time, while drivers use their household items. This means APU batteries need to be able to cycle better than ones required for starting. Reserve capacity is determined by how many minutes the battery can maintain voltage above 10.5, so a battery with higher RC will be able to run accessory items longer. By choosing the right APU batteries they will last longer, which will reduce battery costs overall.