Heavy Duty Trucking, January 2018

Jacobs says 24 volts might take us out 10 or 15 years but then wed be at capacity again with very limited potential for expansion Going right to 48 volts would last longer before having to upgrade again It also gives OEMs a lot more flexibility in how they design vehicles The Australian trucking industry uses both 12 and 24 volt electrical systems because they use both European and North American equipment Mathew Jenkins global engineering and sales director for lighting system supplier Optronics International is based in Australia and has some first hand experience using both systems Australia leans to the 12 volt architecture he says Our trailers are 12 volt but some of our power units are 24 volt That forces us to deal with reducing voltages but that is fraught with other problems Voltage reducers are not linear he says They will take 24 volts and turn on and off very quickly producing an average voltage of about 11 volts over time Thats very much like how an AC circuit works so devices like electronics motors LED lighting etc do not respond well to that sort of signal Voltage drop over distance like with our multi trailer road trains makes it even more problematic In North America we can avoid those challenges making the jump only once if its carefully orchestrated As an industry we should have gone to 24 volts years ago says Bruce Purkey chief creative engineer at Lowell Arkansas based Purkeys Electric Wed be further ahead than we are today but wed still be close to the same capacity limits on the system 24 volt systems would still not be up to some of the advanced technologies engineers are talking about today Purkey suggests going to 24 volts would help but it would be costly and of limited value in the long run because of future demands on the system When one looks at mild hybrids and the likes 48 volt electrical systems for accessories can be desirable says John Bennett general manager of global product strategy and advanced engineering for Meritor They will require roughly four times less current than a 12 volt system reducing the amount of copper required and reducing costs With mild hybrids 48 volts could also mean all electrified components operate at the same voltage simplifying the system Hurdles for 48 volt migration Systems operating at 48 volts would open up huge possibilities for fuel savings and emissions reductions while fundamentally transforming the basic vehicle electric and electronic E E architecture and the way Class 8 trucks are designed and built Switching to 48 volts would probably take close to a decade and would come with a long list of challenges But that list would still be significantly shorter than the list of opportunities In December 2015 the Future Truck Committee of the American Trucking Associations Technology Maintenance Council issued a discussion paper on the topic Exploring the Potential for 48 Volt Commercial Vehicle Electrical Systems Changing the Electrical Electronic Face of Trucking In it the authors outlined some of the challenges While 48 volts is not far from 12 volts in physical terms real world issues are a cause for concern Current 12 volt designs wont automatically work at 48 volts even simple fuses will not migrate let alone dimmers and active load controllers Some fuse panel and harness makers have found that common 12 volt mini and maxi fuses do not behave properly at 48 volts They can fail to interrupt excessive currents properly causing serious overload conditions Also interconnection technologies have evolved for optimal cost and performance in a 12 volt environment The present design of connectors circuit breakers and relay contacts may not be optimal at 48 volts Therefore manufacturers must re evaluate component suitability for the higher voltage JANUARY 2018 HDT 61 WWW TRUCKINGINFO COM Thinner wiring can be used with 48 volt systems That opens up opportunities for component packaging and truck wiring SOURCE TMC SYSTEMS