03Delco Oversizing and Alternator Tech Tip130003232021
TECH Tips CATALOG NUMBER 03 www.midwestwheel.com Order NLINE ™ www.midwestwheel.com Order NLINE ™ Fuel Savings If you choose an alternator that has approximately double the rated output of what your system requires, then you are essentially oversizing your alternator. For example, most on-highway vehicles have about 65 to 85 amps of electrical loads turned on when operating. While an alternator may be rated for a specific output, it runs most efficiently when it’s operating at roughly 35 to 50 percent of that rated output. A more efficient alternator always decreases your fuel consumption. Longer Alternator Life With an oversized alternator only using 35 to 50 percent of the alternator’s rated output, you are reducing the amount of strain on the alternator. This means the alternator is running much cooler and isn’t being tasked as much either. And this all results in increased bearing grease, rectifier diode, and stator insulation life. Benefits of Oversizing an Alternator Better Battery Life Another added benefit of oversizing the alternator is the positive impact it can have on your batteries. You’re able to reduce the depth of a battery’s discharge— also known as cycling. That’s because an oversized alternator produces more output at lower speeds, including idle. That increased output prevents the battery from having to help supply the load—and this keeps it at a more ideal state of charge. The battery cycles less, which translates into better battery life. With three to four batteries per vehicle, you can see how extending battery life can be a big benefit. When making the smart decision to oversize your alternator, keep in mind that the original alternator cables may need to be upgraded to realize the full value. When managing a fleet, the goal is always to get the most out of your equipment. We’ve got an innovative way for you to do just that: oversizing the alternator.