needed. On the alternator, pay close attention to
the cooling ports.
“You can typically just brush those areas clean
of dirt and debris,” Hopko says. “Also, be sure
to regularly check alternator belt tension and
If corrosion is present, a more thorough cleaning
will be needed. Th at’s why it’s important to
regularly inspect the connections before anything
gets out of hand.
On that note, Steele says an occasional steam
cleaning is something fl eets can benefi t from.
“We see many bus transit customers doing
this monthly,” Steele says. “A lot of sand, salt, oil
and other road grime gets up under the hood. If
you have loose joints or connections, this can
become an even bigger problem. You don’t need
20 Fleet Maintenance | June 2018
a pressure washer or any
special solvents to help
keep it clean. A nice, hot
bucket of water will
oft en do.”
cleaning and maintenance
for not only electrical
system longevity, but
also vehicle effi ciency.
Energy is taken
out of the engine
to create electricity.
wastes that energy.
Th us, reduced voltage
drop increases energy
effi ciency. And, increased
energy effi ciency increases
“It’s probably not enough to
notice every time you fi ll up,” Steele
says. “But if you put on 100,000 miles
in a year, that’s going to add up.”
Choosing the right replacement
At some point fl eets will likely need to replace
a starter and/or alternator—or perhaps want to
upgrade to a more effi cient option.
“Always go with an OEM-quality product,”
MAHLE’s Hopko says. “Th ere are many aft ermarket
products out there that say ‘new,’ but
are inconsistent when it comes to quality.
You’ll never go wrong when dealing with top
To that end, Hopko says reman is a solid option,
so long as the starter or alternator is remanufactured
using OEM-quality parts. Whichever route
fl eets choose to go, Hopko has one other piece of
advice: Don’t skimp.
“When you have to replace a starter or alternator
on a Class 5 to Class 8 truck, it’s important to
choose one with at least the same amperage and
kilowatts,” Hopko says. “Some fl eet managers
want to save a few bucks, but that isn’t a good
idea. You’re always better to have too much than
Th is means adjusting and increasing the specifi
cation output accordingly, also referred to as
“oversizing” the starter or alternator.
Starters are fairly straightforward. Gearreduction
starters have become the most
common due to their lower power consumption
and increased torque. Th ey cost more, but the
benefi ts are generally perceived to outweigh the
“Gear-reduction starters put less drain on
battery charging systems,” Hopko says. “So you
really shouldn’t skimp here either. Th ink about
this: A refrigerated unit could lose a full load, and
that would be far more costly.”
Beyond that, a higher-kW starter should be
considered if operated with high parasitic loads
on the engine or in cold-climate regions.
“When in doubt, go with a higher cranking
output,” BorgWarner’s Steele says.
Alternators are more dynamic and give fl eets
more to think about.
“You have a choice between internal and external
fans,” Hopko says. “Regulators are multi-function
and must integrate with the vehicle’s
computer system. Th at can be problematic from
a compatibility standpoint. It’s important to have
a good supplier to help match the right alternator
to your vehicle and its application.”
Application is an important consideration.
One thing to be aware of is if conditions have
changed since an alternator was last spec’d for
a given vehicle.
“If average loads have increased, you’ll want
to upgrade to a higher-output machine,” Steele
says. “A good rule of thumb is to size the alternator
so that the average alternator demand is less
than half of the rated output. When upgrading
to a larger-output alternator, cable sizing should
also be checked to assure it will meet the voltage
drop requirements at the rated output.”
So how does a fl eet identify a vehicle’s average
“As a rule of thumb, long-haul trucks, and even
sleepers, generally average 50 to 70 amps over
time,” Steele says. Th us, fl eets would want a 100-
to 140-amp alternator at the very least.
Fleets also have to consider usage patterns and
the eff ect they have on battery drain.
“Th ere are always peaks, like when running a
microwave or TV,” Steele points out. “Sometimes
and connections can
save a lot of time and
» A vehicle’s electrical system is pretty
straightforward, but there’s a lot going
on within that chain of events. Thus,
there’s a lot that can go wrong.
Image courtesy of BorgWarner
» Delco Remy’s 40SI High
Output Brushless Alternator.
Photo courtesy of BorgWarner