Idle reduction is about cost savings and driver comfort.
Battery-powered heating, ventilation, and air conditioning (HVAC) systems help fleets deal with cab climate control, by providing climate control to the truck cabin while the truck is parked. Fleet users benefit because the systems are quiet and produce no emissions, but they may not provide enough cooling capacity for long rest periods or when operating in very hot temperatures.
They can be powered by a set of batteries on the tractor or come with a plug-in capability for battery charging and/or operation while connected to an electrical power source. They are also called battery APUs and battery EPUs.
Battery HVAC systems need no diesel fuel and produce zero emissions
They are quiet to operate and require few moving parts
They reduce fuel costs associated with idling and have lower maintenance costs
They have limited ability to provide enough cooling for long rest periods
Their battery life expectancy is currently only two years
A larger alternator may be needed because of increased electrical load
Battery HVAC are among the more expensive idle-reduction solutions
Some of the systems operate on 12V power generated from a bank of Group 31 Absorbed Glass Mat batteries and use an inverter to convert DC power to AC power. Others simply operate on 12V DC power. Cooling capacity ranges from 4,600 to 10,000 Btu/hour.
Battery HVAC systems are one of the anchor technologies of an overall idle-reduction strategy. Here are some of the common fleet strategies for adopting these systems successfully.
Best Practices Study
As part of a CK Commercial Vehicle Research project, a small sample of maintenance directors and vice presidents of maintenance at heavy-duty fleets were asked about their idling practices. Fleets who responded to the survey were most dissatisfied with battery HVAC systems as an idle-reduction solution.
Executives from 11 for-hire truckload carriers were personally interviewed to find out about their idle-reduction practices. No single technology was used by all 11 of the fleets, but six have battery HVAC systems on their vehicles.
Here are comments from several of the survey respondents
- In hot weather, battery HVAC systems only last a certain period of time especially if the driver is also using it to run other devices in the cab.
- I like the direction the battery HVAC is going in, but they are too expensive right now.
Internet Fleet Survey
In conjunction with Michelin, the study team surveyed 200+ members of Michelin’s Fleet Forum. When asked what idle-reduction technology they would purchase, 15.7% said battery HVAC systems, but more than half the respondents said they had no experience with battery HVAC systems.
Internet Owner-Operator Survey
In conjunction with Kevin Rutherford’s “Let’s Talk” truckers’ satellite radio forum, the study team surveyed owner-operators and small fleets. 63% of the survey respondents said they had no experience with battery HVAC systems.
When asked why they chose battery HVAC systems for idle reduction, here is what some of them said:
- You get reasonable climate control with a minimal investment.
- If the system is set up correctly, it saves money in the long run.
- There is no extra motor to deal with.
There are already a wide variety of payback calculators for any given type of idle-reduction system. In an effort to meet the industry’s need for more information, we have also developed a high-level payback equation to aid fleets in choosing the right combination of technologies.
Some truck manufacturers offer battery HVAC systems as factory options. Here is a breakdown of what the truck manufacturers offer:
Battery HVAC systems are seen by some as zero-idle solutions because they do not use any kind of engine when in operation. These systems capture energy produced by the truck engine’s alternator when the truck is running and stores it in AGM batteries. When the truck engine is turned off, the energy stored in the batteries can be used to power air conditioning and hotel loads and in some cases heating systems. To get the most from battery HVAC systems, drivers should pre-cool their trucks, pull curtains between the cab and sleeper and use window shades.