Specs that Payback

| July 01, 2009

Size makes a difference. “Select component sizes for the job,” Zehnder says. “If you don’t need heavy-duty components, don’t spec’ them. You’re paying for them every time you fill up.”

Harrington proposes a possible exception, oversize brakes. “One area to improve the performance of your vehicle is to consider a larger steer axle brake (16 by 5) and larger rear brakes (16.5 by 8.62). The advantage is more brake surface that actually increases the distance between relines.”

Larger brakes run cooler and increase wear miles significantly. If these brakes allow you to trade your vehicle without a reline, this option could pay. Front disc brakes offer extremely long maintenance intervals. Having stability control makes sense, too.

Bud Radowick, manager of fleet performance at Thermo King, says many fleets using the Thermo King diesel-powered auxiliary power unit have safely lengthened their oil change intervals by 10,000 miles because truck engine idling drops below 5 percent. He adds that the elimination of up to 30,000 hours of idle time, which a buyer can see via the engine control module, enhances resale value.

Truck manufacturers recommend an APU as a means to reduce operating costs and enhance resale value. Volvo supplies one designed to be easily removed and installed on your next vehicle, Bio says.

Harrington says, “The new path is toward electrically driven HVAC systems that operate off of a second set of batteries. These provide eight to 10 hours of performance and have the batteries recharged during normal driving. Combine them with a shore power connection and an inverter/charger and you have a lower carbon footprint.”

Manufacturers say one solution is to use an adequate set of absorbed glass mat batteries, which accept charge more quickly and handle deep discharge cycles better than traditional lead/acid batteries. Warmkessel says Mack’s Idle-Free system meets Technology and Maintenance Council recommended practice standards, which guarantee adequate overnight heating and cooling even in extreme conditions. It has four AGM batteries that are separate from the starting batteries.

Zehnder says Kenworth’s Clean Power system combines a shore power connection, an inverter and a storage cooler for overnight air-conditioning. A separate 110-volt A/C compressor recharges the storage cooler using alternator power sent through the inverter as you drive.

In any battery-powered overnight system, International’s Morino recommends a four-battery setup with 2,600-2,700 cold cranking amps and deep-cycle capability. “You need a balance between CCA and re-chargeability,” he says. Peterbilt’s Marko says, “There is strong interest in AGM batteries these days. These accept volt drop better than a lead/acid battery and will handle this kind of usage, while performing reliably and giving long life.”

Whenever using overnight battery power, use an oversize alternator big enough to do the job.

Another recommendation from International is to set up remote voltage sensing at the batteries to help the alternator adjust its output to conditions. Add a low-voltage cutoff and shore power connection, and you’re in business.

Peterbilt’s Marko specifies LED running, marker or interior lights. These will reduce maintenance requirements and save fuel. Zehnder recommends high-intensity discharge headlamps, an option that increases headlamp life as well as visibility.

The manufacturers also say that items like unitized hubs (standard on some Volvo front axles) and low-maintenance, permanently greased driveshafts more than pay their way.

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