Bringing electrical power to the people on the road
Today's truck-based offices are equipped with the works - telephones, computers, fax machines, televisions, VCRs, microwaves, refrigerators. Suddenly, the big question on that handy new fold-out desk is, "How do we power all this stuff?"
One solution is to use the same power that office workers use to drive their equipment, alternating electrical current, or good old AC. Several converging factors may make the use of AC a viable option for fleets in the very near future: truck-stop electrification, the availability of high-performance inverter/chargers, and the growing economic and social pressures on fleets to dramatically reduce engine idling.
"Until recently, bringing AC power to trucks has been a chicken-and-egg sort of problem," observes Gerald Baron, executive director of the Truck Stop Electrification Alliance (T-SEA), an organization formed to facilitate cooperation among the various stakeholders in the truck-stop electrification process. "In the past, if you talked to truck manufacturers about installing AC outlets, they'd ask, 'Why? There's no place for trucks to plug in,'" Baron recalls. "When you discussed installing AC power hookups at truck stops, it was the other side of the same question, 'Why should we electrify? Trucks aren't equipped to use AC.'"
Today, truck stops and OEMs - with Freightliner Corp. and TravelCenters of America, and Volvo Trucks North America and Petro Stopping Centers leading the way - are forming alliances of their own to serve that most-mobile businessperson, the driver. This has the potential to radically alter power problem parameters because the whole solution no longer necessarily has to fit on the frame rails.
The availability of high-quality, commercial-grade inverters for trucks is also lending support to the AC power option. Inverters for converting 12 VDC into household AC have been around for some time, of course, but the lack of standard testing and certification requirements for consumer-grade machines has muddied the purchase decision for aftermarket buyers and given inverters a mixed reputation for performance.
"The result is that manufacturers have each come up with their own performance ratings," explains Kevin Hagen, manager of new business development for Trace Engineering, Arlington, Wash., a supplier of inverter/chargers for heavy-duty trucks. "Early engine horsepower ratings had the same problem," he adds. "No two manufacturers rated the same way, so it was impossible to make comparisons.
"Now, according to Underwriters Laboratories (UL), the independent agency that writes the safety standards, the true rating is what the inverter will deliver continuously at its rated ambient temperature," Hagen says. "Unfortunately, many of the light-duty, 'plug-in' inverters don't use the standard, so the only way to be sure about power rating is to look for units listed to UL 458."
What should an inverter/charger do for drivers? Trace's own Truck Series inverter/chargers, for example, are designed to convert battery DC power to AC to run equipment, electronics, appliances, and other conveniences. The battery protection feature in the Truck Series units shuts down the AC output before battery voltage drops too low. With a "shore power" cord drivers can also plug into any AC power, and the Trace units will pass AC to all appliances plus charge the batteries at the same time. Not bad.
Fleet owners have good reasons to encourage AC availability. According to Argonne National Laboratory, idling costs up to $4,000 in profits per average longhaul truck. That's $4,000 per truck, per year. Maybe "AC" really stands for "additional cash."