Loads on the electrical systems of today’s heavy-duty vehicles have increased significantly. This makes it very important that electronics be spec’d and maintained as a system rather than as individual components working together. That was the first message that BorgWarner’s Brian Thompson shared with the audience at a recent NationaLease meeting.
When troubleshooting a vehicle’s electrical system, you will need the proper tools and know how to use those tools properly. Thompson recommends having a multimeter, carbon pile, clamp-on ammeter, and microprocessor-based tool for troubleshooting the electrical system.
He reminded the audience that batteries have several key functions:
- Cranking the vehicle.
- Providing off-key power to supplement loads when the electrical load exceeds the alternator output.
- Acting as a shock absorber for the electrical system absorbing and smoothing out transient voltage fluctuations.
Batteries need to be protected from heat, which shortens their life, and from vibration. In addition, batteries only have a set number of cycles and deeper cycles significantly reduce battery life.
See also: Clark: Prepare today to service the vehicles of tomorrow
When checking the condition of the batteries, you are determining state of charge, which is a measurement of the specific gravity of the electrolyte and the condition of the plates. Thompson says that a fully charged 12-volt battery will read approximately 12.6 volts or more and that 12 volts is “essentially a dead battery.”
When it comes to alternators, proper spec’ing is critical, so work with your OEM and component supplier to make sure you get the right alternator for your needs. When determining the size of the alternator you need, factor in the vehicle’s application. Also look at whether it has an APU, a battery-powered HVAC system, a lift gate, or other miscellaneous accessories. Accessories use more power than you think.
Thompson provided the following statistics:
- Using a microwave oven for 10 minutes consumes 18.3 amp-hours.
- Charging a laptop for 120 minutes uses 14.6 amp-hours.
- Watching television for 120 minutes consumes 7.33 amp-hours.
It's likely that a sleeper tractor could have all those devices or more in them.
Be diligent in performing preventive maintenance on your vehicle’s electrical system. Check the integrity of wire connections and the wiring harness and ensure all connections are clean. Replace damaged or corroded wiring as needed or you could experience excessive voltage drop.
To ensure a long life for your vehicle’s electrical system, remember to treat it as a system, make sure you spec it for the vehicle’s need, and follow manufacturer recommended preventive maintenance schedules.
Jane Clark is vice president of member services for NationaLease. In this position, she is focused on managing the member services operation as well as working to strengthen member relationships, reduce member costs, and improve collaboration within the NationaLease supporting groups. Prior to joining NationaLease, Clark served as area vice president for Randstad, one of the nation's largest recruitment agencies, and before that, she served in management posts with QPS Cos., Pro Staff, and Manpower Inc.
