Fleet Maintenance - 20

Multi-voltage vehicles

Successfully implementing multiple voltages
throughout a heavy duty vehicle will require
innovation in order to deliver the different, and
proper, voltages to select components. For example, consider vehicle lighting. Commercial vehicle
lighting supplier Optronics has designed a voltage
reducer that is inside each light in order to address
this need in a multi-volt environment.
"Say there are 48V coming in and the light
only needs 12V to operate; it will go through a
component [such as a voltage reducer] to step
that voltage down to the 12V that it actually
needs to run that light," says Kyle O'Dell, director of engineering and new product development, Optronics. "Most LED lights are running
off [of a] lower voltage than even 12V. So really,
you're stepping the voltage down anyway ... If
you design a light for a 48V system, it's just like
designing a light for a 12V system. You're just
going to use different circuitry on the front end
to get that voltage to the correct output for the
LEDs to function properly."
Currently, Optronics delivers voltage reduction
capabilities in their lighting to the Australian
commercial vehicle market, a market that is
already operating in a multi-voltage reality with
12V and 24V systems on single vehicles throughout the country. O'Dell confirms the company is
working to develop voltage reduction within their
lighting capable of operating in a 12V to 48V range
for the North American market.
Potential problems may arise when components are added to multi-voltage environments
with varying degrees of wiring. Organizing and
designating wiring throughout a multi-voltage
vehicle to indicate and set aside specific voltages
per wire may help to alleviate potential issues
when implementing new componentry.
"One thing you need to caution people on is
when they do reduce wire gauge size, they need
to make sure that they're not going to add accessories to it in the future that would overload that
system," O'Dell warns. "No matter what the voltage
system is, you need to be careful on your harnessing to size it properly for anything that you would
add in the future as options to those vehicles."
Another option aside from voltage reduction
capability per component would be custom
harnessing per vehicle. USA Harness manufactures custom power distribution centers (PDCs)
to accommodate vehicles with varying voltage requirements. USA Harness is a division
of Optronics.
Custom PDCs can negate the guessing game
that may come with installing components into
a multi-voltage vehicle. Different vehicles have
varying electrical demands. O'Dell speaks to
the range of electrical demands required of an
armored courier and the solution USA Harness
delivers in such an instance through the creation
of custom PDCs.
"In the case of armored couriers, there are over
100 circuits," O'Dell explains. "We build custom
power distribution centers where we break down
voltage for certain things and leave voltage
higher for other components. We can tailor that
design where you can have multi volts [with dedi-

20 Fleet Maintenance | April 2020

»Vehicles operating with larger air compressors,
additional hydraulic systems, and other electrical
demands benefit from the organization custom
power distribution centers and harnessing offer.
Image courtesy of USA Harness

cated connection sections], where one section is
a 12V [and] another section is 48V. On the PDCs
for these armored cars, there are actually four
different fuse block sections, so you could run
on four different voltages."
USA Harness also sees the utilization of custom
PDCs viable in car carriers, heavy duty tow vehicles, and work trucks; vehicles operating with
larger air compressors, additional hydraulic
systems, and other electrical demands benefit
from the organization custom PDCs offer. As
commercial vehicles further integrate technology and electrical systems, customized PDCs
may offer efficient, safe, and simple installation
options. Creating designated areas of connection
for varying degrees of voltage helps to navigate
the installation and maintenance of electrical
components and minimize the risk of issues,
such as: installing components to wiring that
deliver improper voltage, damaging components
that do not feature voltage reduction capability
should they be installed into a wire delivering too
high of a voltage, overloading wiring with voltage
demands, and more.

Maintenance considerations
with higher voltages
When it comes to higher voltage and multi-voltage systems, the procedures, practices, and tools
used in electrical maintenance will be changed
to ensure safety and efficiency.
Prysmian Group's Kelly serves as the chairman of the Society of Automotive Engineers
(SAE) Cable Standards Committee, as well as the
chairman of the SAE Truck and Bus Electrical
Systems Committee.
"At the SAE Truck and Bus Electrical Systems
Committee, we are analyzing all of the old documents, reviewing what should stay 12 [volt], what
should be updated to include the multi voltages,
and what needs to be written that hasn't been

written yet," Kelly says. "And we're on the path.
We actually developed a roadmap; we had a
multi-voltage task force that was created that
identified all the needs, [and] gave advice and
recommendations [on] how to get there. We've
taken that roadmap and we're beginning to follow
it and beginning to do that work."
Kelly is also sponsoring a proposal, titled
SAE J3176.
"It's cable marking for circuit identification and
multi-voltage power distribution systems ... We
need to communicate to the technicians clearly
so that they know what they've got and how they
can quickly analyze and go after repair. Part of
the goal ... [is] to standardize this regardless of
truck brand," Kelly says.
The proposal determines standardizing cable
coloring to represent different voltage levels. Red
cables would indicate 12V, yellow cables would
indicate 24V, and blue cables would represent
48V. Orange cables would indicate 60V or higher,
signifying high voltage. The idea is to eliminate any
misinterpretation of the voltage a technician would
be handling when servicing electrical wiring. The
proposal also sets forth color standardization for
the grounds. 12V, 24V, and 48V will have black and
white-colored grounds; the differences per voltage
will be indicated through striping patterns.
Kelly is also working with the Technology
and Maintenance Council (TMC) to develop
new Recommended Practices (RPs) for handling
multi-voltage system maintenance procedures.
Purkey's Rambeaux speaks to the TMC RPs
already in place that are more important now
than ever as vehicles transition into a multi-voltage environment.
"For example, in TMC, we have RP 129, which
is voltage drop testing from batteries of the
starter or from the alternator cables back to the
battery. You can have the best battery in the
world, the best [vehicle] in the world, and the
best alternator in the world; if you don't have
good cables, nothing's going to work right,"
Rambeaux says. "Very few fleets do those tests
now. If we went to 48V, we get to make those
battery cables a lot smaller. It's going to become
even more important because now if instead
of a 2W battery cable, [you] maybe [have] a 1W
cable; that is a lot less cable, and when it does

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