Alternators and batteries have become more powerful to handle these larger loads, but many technicians are getting caught up trying to analyze complicated systems and making unnecessary repairs when many problems can be solved by remembering a few basic steps.
The role of the technician is evolving to include more electronics knowledge, and while there are new gadgets to help them do a better job, keeping your techs focused on the fundamentals of electrical systems is your best bet for running a productive and profitable shop.
Power-packed alternators are as popular as ever these days, and Pete Sremac, commercial market manager for the Evanston, IL-based alternator manufacturer C. E. Niehoff & Co., says their brushless design helps maintain an efficient electrical system for big rigs that need plenty of juice for long hours of idling.
"When you've got a 10-kilowatt or a big alternator like that, the difference in efficiency can equate to several horsepower because it takes about 25 horsepower to drive an 18-kilowatt alternator," he says. "Now you're getting into something that's more significant that begins to be noticeable in fuel consumption. It adds up over time and we've done some calculations in fuel savings over time based on full output from these large alternators (heavy-duty transit bus), and you can save about 1,000 gallons a year, depending on the duty cycle."
It's all part of the drive to satisfy the growing demands of the industry, says Sremac.
"Years ago, 200 amps on a bus was OK, but now it's 300 or 400 or more," he says. "It's the same with emergency vehicles—they are looking 400-500 amps as a normal electrical output. Radios and computers don't take a whole lot of power, but they've got a whole lot of them. It all adds up."
C. E. Niehoff engineer James Becker says the result can damage even powerful batteries.
"An alternator may be rated at 400 amps, but at idle speed you're only getting half of that," he says. "So where does all this extra power come from? You're depleting your batteries."
The real killer of electrical systems is when a driver shuts the truck off but doesn't turn loads off, says Bruce Purkey, President of Purkey's Electrical Consulting and the long-time Vice-chairman of TMC's electrical study group.
"Truck load haulers run their 14 hours and shut the truck off, and now they want to have air conditioning, their inverters, television, popcorn—they want the comforts of home," Purkey says. "And then when they do that—and 26 states have enacted anti-idling laws—they shut all the truck off so guess what has to take all the load? The batteries. You're going to shorten their life."
These increased loads are driving the need for more consistent power from reliable batteries. Technical product manager Kalyan Jana from the Reading, PA-based stored energy manufacturer Enersys says sturdy dual-purpose batteries like their Odysseys can reduce at least a few headaches for fleet managers.
"They can lead a more peaceful life—they won't have to worry as much about batteries," Jana chuckles. "For short-term, high-rate discharge for engine start application, it (can deliver) very high-energy pulses—at the same time, if you take it down to 80 percent of its capacity, provided you charge it properly, it can do that 400 times."
Dual purpose batteries have been in the consumer market for only the past four or five years, Jana says, so he ends up spending significant time educating buyers about the value of this more expensive option.
"You have to pay more up front, but think of the time you'll save because you don't have to do periodic maintenance checks, you don't have to go in and clean out the battery tray because there's no acid crud," he says. "You can lay these batteries on their sides—the battery tray will remain clean. All those maintenance costs are gone."
Jana says duals are growing in popularity among fleet managers because they have gotten sick and tired of dealing with battery problems.