ownerdriver.com.au AUGUST 2019 27
“THE IDLEPRO ALTERNATORS DELIVER
INDUSTRY BEST OUTPUT AT LOW ENGINE
SPEEDS.”
Any alternator’s advertised output rating is at a
stabilised 24°C (SAE J56 standard). The alternator
output achieved at the normal under bonnet
operating temperature of the truck (~125°C) will be
considerably less than the advertised rating. It is
important to ensure the output of the alternator at
operating temperature will exceed the combined
electrical loads of the truck and the electrical
accessories that are installed.
Using an example of a road train departing at
6pm from Townsville to Mount Isa, let’s assume the
electrical accessories listed in Table 1 are working
for the majority of the 10-hour trip. The electrical
requirement at this stage is approximately 155A.
When the truck stops at a set of traffic lights
or a rest area, the alternator output is about 70
amps at idle, which implies that the batteries are
discharging to assist the alternator in providing
power to the system.
Upon arriving at Mt Isa, the battery may be
further discharged, at times to less than 10.5
volts. A deeply discharged battery (below 11.9
volts) may not start a truck or potentially may
even damage the starter motor because the starter
motor does not get the required voltage to engage
or disengage correctly.
The costs to maintain an adequately rated
electrical system are minor when compared
to downtime, loss of contracts, penalties and
component replacement.
To ensure the correct alternator is fitted to the
application:
- assess the electrical accessories on your truck
(refer to Table 1) - ensure the alternator output (amps) at operating
temperature is able to cover all the electrical
loads of the vehicle. The type and the rating
of the alternator you need will depend on the
nature of your transport application and the
amount of time your engine idles - it is important to note that ensuring the
alternator will provide high output at low
rpm is critical to exceeding the electrical load
requirements found in modern vehicles fitted
with aftermarket accessories and options.
PACCAR Parts recently added the new Prestolite
IdlePro range of alternators to its distribution
network.
“We are seeing a number of new and older
vehicles that have higher electrical loads due to
the nature of their application upgrading to these
high-quality alternators,” Mohan says.
“The IdlePro alternators deliver industry best
output at low engine speeds (63 per cent efficiency
at idle) thus reducing loads placed on the batteries
and also reducing wear and tear on starter motors.
We want to educate more operators on upgrading
the electrical systems, to ensure a balanced and
reliable charging system.”
Figures 1 and 2 compare the performance curve
of various alternators at 650rpm and 1,450rpm.
This output is measured at normal under bonnet
operating temperature.
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systems and engine performance through their
various features that help extend battery life
and increase vehicle uptime. They are available
in 170, 190, 210 and 240 amp ratings with both
J180 hinge mount and pad mount. They come
with a warranty of two years/500,000km
(conditions apply).
IdlePro alternators can be purchased at
57 PACCAR Parts and TRP dealerships across
Australia and New Zealand. Supported by skilled
technical product assistance staff, the PACCAR
Parts dealership network will support customers
promptly and efficiently.
PACCAR Parts dealers stock a wide range of
genuine and name brand replacement truck parts
to fit all Kenworth and DAF models, as well as most
other heavy duty truck and trailer makes. PACCAR
Parts prides itself in sticking to its three principles
FIGURE 1
FIGURE 2
- unmatched stock availability, quality parts and
reliable technical expertise.
Look out for a price promotion on the IdlePro
alternators in the PACCAR Parts July-August
catalogue. For more information or to enquire on
stock availability, please contact your local dealer
or visit w w w.paccarparts.com.au/find-a-dealer.
PACCAR Parts would like to thank Prestolite Electric
and Centur y Yuasa for their technical advice and
contribution to this article.