Wired For Profit: Today's Electrical Systems
August 2010, TruckingInfo.com - Feature
The more things change, the more they stay the same. Nowhere better does that expression resonate than with heavy truck electrical systems.
A cut here, a splice there: Today's complex electrical systems won't tolerate jury-rigged repair jobs. There are fewer and fewer user-serviceable systems on trucks. (Photo by Jim Park)
One of the biggest challenges is integrating emerging technology into legacy infrastructure - the seven-pin-based wire-and-harness systems that have hardly changed in decades. New technology emerges almost daily, but unless it can be made to work within or alongside existing technology, it'll never see service on a truck chassis.
You cannot make wholesale changes to electrical infrastructure because of the need for backward compatibility. What we are seeing instead is more creative use of existing hardware.
Take wire, for example. It's no longer just a conduit for electrons. Thanks to multiplexing, it's also a pathway for messages, fault codes, activation signals, and more. There's less wire aboard most power units today, which is good, but systems are still prone to malfunction and failure due to common problems like corrosion and breakage. And don't even think about tapping into or adding loads to a multiplexed circuit. Something as benign as a chicken light can sideline a truck.
Starting and charging systems are expected to deliver as they always have, yet they work harder today than ever in a more hostile environment. Under-hood temperatures are greater, demand on batteries is greater, and today's engines are harder to turn over. On top of that, anti-idle laws have increased starter duty cycles, while hotel loads and electric climate control are taxing batteries and alternators to their limits.
In other words, it's a fine time to be in the electrical business.Heat-sensitive components
Despite all the advancements, electrical problems still dominate the truck repair world (with the exception of tires). They are primarily weather-related, says Jerry Bodkins, a master-certified technician who works at Travel Centers of America's Youngstown, Ohio, location. He's also a master instructor at TA's technician training facility in Ohio.
"Hot or cold, wet or dry, it doesn't matter," Bodkins says. "When we see extremes in weather and temperature, the bays fill up. Heat and cold are both real hard on batteries, starters, and alternators. Our number one area of concern is the electrical system, and that's probably never going to change."
Bodkins says heat has always been a concern relative to alternators, and that situation worsened in the months following the introduction of the first exhaust-gas recirculation systems to meet emissions regulations starting in October 2002.
The hotter electrical products run, the less reliable they are over time. Largely, that's been remedied by more robust alternators, says Kent Jones, vice president of heavy-duty sales and marketing at Remy International.
"Alternators engineered to pre-2004 (pre-EGR) under-hood requirements were built to handle temps in the 93-degree C range (about 200 degrees F)," he says. "Today we need something capable of handling temps in the 110- to 115-degree range (230 to 240 F). Ten degrees doesn't sound like much, but it sure was hard on alternators."
You might need to stock three different specifications relative to temperature or output, Jones says. "Locally rebuilt product or will-fit units may not meet today's fleet requirements."Hard starting
The changes wrought by the Environmental Protection Agency's emissions reductions mandates have had another impact on engines: Tighter tolerances and extremely high pressure fuel injection mechanisms have added load to the starter motor's job, and by extension, to the batteries.
Bodkins says he has seen more battery failures at relatively young service life in post-EPA 2007 engines. There's really high demand for cranking amps with the new engines, he says, and that has prompted a few OEs to install absorbed glass mat (AGM) batteries.
"There's more punch in the new batteries than the older lead-acid batteries," he says. "They get the job done, but they bring a few other issues to the table. They are completely different batteries. They require different testing equipment, and different charging equipment. You can't just push amps into them like you could with a lead-acid battery. And you have to be careful jump-starting them."
On top of that, anti-idle regulations are taking their toll on batteries and starting systems. Jones says idling restrictions mean engines aren't running all the time anymore, which places two demands on the system.
"One, any electrical demand during engine-off time is coming from the battery. If the alternator isn't running, it's not producing any charge. Funding those electrical requirements is taxing batteries harder and harder," he notes. "And two, where once a driver might have started the truck only a few times a day, today we're shutting the trucks off every time we stop, and that's increased the number of starts to 20 or 30 or more per day. That will shorten the life expectancy of a starter."
In the mid-'90s, alternators produced 100 amps at 12 volts. By 2000, we were up to 130 amps at 12 volts. Now, the specifications call for 160 amps for a standard truck. Trucks with electric climate control systems and large hotel loads are calling for greater than 200 amps.
"We've come a long way in 10 years, doubling the alternator and starter output and dealing with the elevated temperatures," Jones points out. "The concern for the aftermarket is ensuring replacement parts are up to the task. Customers are naturally going to be concerned about cost, but you can't shortchange them on capacity."Lightening the load
Truckers haven't caught too many breaks in recent years, but one that comes to mind is LED lighting. It's common today, and for good reason. LEDs are bright and clear, and hardly ever burn out. Peterson, for instance, warrants its Piranha brand LED lamps for 100,000 hours. And most importantly, in the context of this discussion, the current draw on a full complement of LED lighting is about 10 percent of a similar incandescent system, Peterson says.
Brad Van Riper, senior vice president and chief technology officer at Truck-Lite, believes the days of incandescent lighting are waning. Certain Truck-Lite lamps are no longer available, and more will be discontinued in the next few years, he says. "The basic Edison-based 60-watt incandescent household light bulb is slated to be obsoleted by 2014, in favor of the compact fluorescent and possibly LED-based lights that will screw into the same sockets," he says.
Fleets that have a good handle on their costs and watch the frequency of change-outs have seen the value of switching to LED, Van Riper says, "I guess if you're looking only at the upfront costs, it could be a barrier, but there's no doubt the lifecycle costs of LEDs are a fraction of incandescent."
When CSA 2010, the federal government's new way of rating carrier safety, comes into full play next year, fleets might become more concerned with lighting failures than cost. Two of the top 10 equipment violations are lighting or electrical-related, notes Page Large, national fleet sales manager at Grote Industries. "At six points apiece, bad lighting could cost a lot more than money."
Grote also offers white LED interior lights for trailers, now featuring motion-sensing on/off switches. The light stays off until it senses motion, so when a driver is moving about inside the trailer, the light stays on. "When the door is closed, or when the driver is out of the trailer, it goes off in three minutes," says Scott Robertson, Grote's program manager for white lighting.Power management
By now, you should have a sense of the tremendous demand we place on our electrical systems. The burden is unlikely to lessen going forward, so the solution has to include better power management.
To get the most out of the electrical system, we'll need a smart technology to manage batt