Horseless power

Some idling options, such as IdleAire, don’t require buying a single piece of equipment. Others, such as gen sets and inverters, require electricity producing equipment and additional appliances such as block heaters and climate-control units. Here are some present and emerging technologies.


Until recently, truck stop operators had little incentive to electrify their parking lots. But attitudes are changing, prompted by a growing demand from customers and a proliferation of anti-idling ordinances.

George Strickland, director of engineering and construction for Travel Centers of America, says his company ventured into electrification in 1995, when it applied for permits to construct a plaza near Willington, Conn. “We agreed to outfit 40 spaces with electrical hookups,” he says. “But in the four years since the site opened, few truckers have taken advantage of the service. Many of them felt the outlets were more of a nuisance than anything.”

Strickland attributes the low use to poor advertising and few trucks wired for shore power. Price certainly wasn’t the problem. He says the facility charges about $2 per night.

Nevertheless, Strickland is optimistic that electrification will gain acceptance among truck stops and fleets. “Until recently, they were too busy hauling freight and more worried about having enough equipment and drivers,” he says. “But now, with fuel prices up, I think there’s a real incentive for them to re-evaluate the situation.”

Rick Tempchin of the Edison Electric Institute also believes the tide is turning. “We haven’t yet nailed down the perfect business model for selling electricity to truckers,” he says, “but at least we have all the pieces to the puzzle.” These include growing user interest, proven truck infrastructure and card-swipe, point-of-purchase systems to reduce the burden on truck stop personnel.


IdleAire Technologies has developed a system that offers every possible utility short of running water -sort of a cross between truck stop electrification and Park ‘N’ View-type service.

After nearly three years of designing and testing, IdleAire launched a pilot program with three units at a New York Thruway rest stop. The program was such a success that IdleAire is dismantling those spaces and planning to build modules for 44 spaces along the Thruway.

The IdleAire module, at the end of a flexible tube suspended from an overhead truss, inserts into the truck window. It provides heat or air conditioning, a telephone line, Internet access and AC electricity, both indoor and outdoor for engine block heaters. “It has to be convenient for drivers if we’re going to change their idling habits,” says Tom Badgett of IdleAire.

Company officials also hope to appeal to truck stop owners, who will pay no installation or maintenance costs, yet share in the revenue, helping to offset a slight drop in fuel sales. At the New York Thruway, eight hours of IdleAire sold for $9.75, paid for with the swipe of a credit card.

Badgett says IdleAire has signed contracts with several truck stop chains, which he declined to name, and plans to begin installation in March.


The auxiliary power unit comes in two general forms. One is a gen set providing 110-watt power for in-cab devices such as climate control systems, block heaters, refrigerators and microwaves. The other drives the truck’s regular DC devices and climate-control systems, but it does not provide 110-watt power.

Auxiliary generators have long been a favorite power source among hard-running, long-haul truckers because they offer complete freedom from external hookups. Gen sets have small diesels and some form of electrical generator. Although this duplicates equipment already on the truck, gen set engines sip, rather than gulp, fuel – around 0.2 gallons an hour, says Truck Gen’s Klaus Holze.

Such generators typically cost between $5,000 and $10,000. Truck Gen’s generators produce 110-watt power, relying on auxiliary heaters and air conditioning units to control the climate. Webasto, a maker of auxiliary heaters, offers an online calculator at that helps you figure how much money you’re losing through idling and the savings that can be achieved with Webasto heaters.

Both Pony Pack and Auxiliary Power Dynamics, unlike Truck Gen’s generators, offer devices that supply DC electricity to the truck’s climate system while keeping the engine warm. The Willis Auxiliary Power System, made by Auxiliary Power Dynamics, generates electricity, provides air conditioning, pumps air, monitors batteries and pre-lubes the truck engine with warm oil. “We run everything except the driveshaft,” co-owner Eldon Willis says.

Willis says his product is unique because it can start and stop the truck’s engine to maintain air pressure, coolant temperature and battery voltage. Just as important, he says, it comes with no weight penalty. This is accomplished by swapping the truck’s normal electrical starter for a much lighter air-driven model, also eliminating the need for multiple starter batteries. “We’re the only company that can put a unit on a truck and not add any weight to it,” he says.

The Willis system sells for roughly $6,500, not including installation. The price is comparable with that of other gen set brands.

Pony Pack circulates heated coolant from a small diesel engine through the truck’s large diesel engine to keep it warm, siphons some of that same hot coolant from the large diesel engine so the driver can operate the truck heaters, and runs a refrigerant compressor to circulate coolant so the driver can operate the truck air conditioner. The Pony Pack also uses an alternator to keep the truck’s battery charged.

The Pony Pack engine uses about 0.18 gallons per hour. It costs $5,600 before installation and weighs about 300 pounds.

Truckers with shore power kits can turn off their engines and plug in. While shore power kits are relatively inexpensive, access to shore power is limited.


Inverters are increasingly the device of choice for truckers wanting to use standard AC appliances. While plenty of well-built, powerful units are on the market, most truckers continue to shop on price or impulse alone, picking up low-output models at truck stops or discount stores. The results are often disappointing and sometimes dangerous.

“Many of those products aren’t up to the task of providing sufficient cab power,” says Brian Lawrence, market segment manager at Xantrex Technology, the nation’s largest inverter maker and the only one in truck manufacturers’ data books. “But they’ve been helpful in showing the industry and drivers that AC electricity is an important tool on the road.”

While low-priced units continue to dominate the market, Lawrence says truckers at least are starting to understand which features they need. Some companies still market products based on their peak-load numbers, but Lawrence says that’s deceptive because peak-load output cannot be sustained very long. Constant-load numbers are a better measurement of performance, he says.

One fairly common problem with all inverters is their ability to drain a battery set to the point that even dome lights barely glow. Such deep discharges are annoying, time-consuming and expensive. They require jump-starts and occasionally new batteries.


New engines can idle comfortably at 600 rpm, substantially lowering fuel consumption. Some engine makers go further with systems that allow drivers to optimize their idling with controls that turn an engine on or off depending on engine temperature. The devices can be retrofitted to more recent engines or added as an option to new ones.

Cummins’ optimized idle device starts an engine to maintain oil temperature. If the temperature of the engine oil drops below a certain point, the engine will crank and idle until the oil temperature returns to a designated range. The company also offers an Optional Cab Comfort control that uses a bunk thermostat to trigger idling, thus warming or cooling the cab using the truck’s climate system.

Detroit Diesel’s Optimized Idler idles automatically to maintain engine oil temperature and battery voltage. In Thermostat Mode, the engine cranks to maintain cab temperature. The system reduces idling by about 50 percent, says Tom Diefenbaker at Detroit Diesel.

Caterpillar offers a Driver Comfort Control System as a retrofit. It will start and stop the engine to maintain in-cab temperature. The system also monitors engine temperature and battery charge to automatically start the engine and recharge the batteries.

Such devices can add $750 to $1,000 to the cost of a new truck. Some truckers say the constant starting and stopping of an engine can disturb sleep.


Starting batteries are the most common source for truckers’ electrical power needs, largely because they’re always connected. This sort of use, however, can cause trouble because these batteries are designed to deliver a lot of energy in brief intervals, then be recharged. Creature comforts drain them slowly and more deeply, resulting in premature failure.

Some truckers try to solve the problem by mounting an isolated deep-cycle battery to supply cab electricity. But such arrangements have their own problems: wiring complexity, extra costs and weight, and inefficient and inadequate recharging.

Several battery makers – Interstate and DayStarter among them – have introduced starting batteries that are better able to handle deep and frequent discharging.

“We call ours an ECL – extreme cycle life – battery,” says Gayle Kimbrough of Interstate Batteries. “It’s not a deep cycle. It is a starting battery with a higher cycle life. It is able to take a little bit deeper discharge than a typical starting battery and take a lot more of them.”

Auxiliary power units like this Truck Gen generator provide power to climate systems and appliances at a fraction of the cost of idling.


Jim Burke has a different solution for battery-related issues: super capacitors. These are basically electrical storage devices so robust that just one can easily spin a large diesel engine. Burke, vice president of Kold-Ban International, says a super capacitor could free up space in a truck’s battery box, allowing truckers to use multiple deep-cycle batteries for their in-cab devices.

Super capacitors, developed by the Russian military, are about half the weight and size of a Group 31 battery. Burke says they differ from batteries because they don’t rely on a chemical reaction to produce energy. “That means ambient temperatures don’t affect them,” he says. “They’re equally powerful at room temperature or 40 below.”

Capacitors haven’t attracted a lot of buyers, mainly because they cost about $1,000. Burke says the extremely high-duty cycle of capacitors, reportedly 250,000 starts, evens out the costs over time.


Cab Comfort, a division of the Dometic Corp., has a unique option to idling: a pair of absorbed glass mat batteries that supply electrical current to a heat pump. The batteries, called Kwyatt Power, and the heat pump, called Duo-Therm, are designed to work together, although it is possible to run the heat pump with shore power or an auxiliary generator and to operate other electrical appliances with the AGM batteries.

Al Haimbach, Cab Comfort’s vice president of sales, says the company started selling AGM batteries because it needed a reliable, accessible power source for its heat pump. Truck starting batteries weren’t up to the task, and too few truckers had gen sets or shore power connections. He says Cab Comfort’s batteries will deliver about 15 hours of electricity in normal conditions, or eight hours if the heat pump is running constantly. They’re isolated from the starting batteries but are still recharged by the truck’s alternator.

“Typically, you’ll be able to recharge our batteries in two to three hours when you’re running down the road,” Haimbach says.

AGM batteries were designed for the aviation industry. They reportedly deliver 30 percent more amp hours than standard starting batteries and provide greater longevity. “Our engineering department discharged them 50 times a day, and they still lasted more than three years,” Haimbach says.

The entire system weighs 370 to 450 pounds. It sells for about $3,500, including installation.


Alternative power sources don’t get any more futuristic than fuel cells. NASA has used them for years to supply electrical power to its spacecraft. A fuel cell basically cracks its source fuel into protons and electrons to generate electricity. The devices will operate on a variety of fuels – hydrogen, gasoline, kerosene, methane, methanol, diesel fuel, etc. – and produce almost no emissions.

Freightliner has been working with XCELLSiS and Ballard Power Systems to develop fuel cell technology for heavy trucks. The companies unveiled a hydrogen-fired auxiliary power unit capable of producing 1.4 kilowatts – enough to run a 7,500-watt air conditioner, television, VCR, coffee maker, interior lights and more.

Bill Gouse, a Freightliner engineer, says the prototype “works remarkably well and makes about as much noise as a laptop computer.” Still, he says, there is a lot of work to do before such hardware reaches the market. Today’s fuel cells are extremely expensive and rather fragile.

Rick Cooper, CEO of XCELLSiS, agrees. “There is a widespread market for fuel cells, but I think trucks will be the first applications,” he says. “The cost of saved diesel fuel alone would justify the product.” Cooper says fuel cells could be ready for commercial use in four or five years, but he won’t even guess at their eventual prices.