OEM alternators can be more expensive than aftermarket alternators, and the price disparity causes many businesses to opt for the cheaper option.
But you might be getting just that – a cheap option.
Why cheap alternators are the wrong choice
Aftermarket alternators are sold as less expensive OEM replacements, but they aren’t always good replacements because they are not identical to the OEM unit. Buyers are often unable to spot the differences in quality, unless they inform themselves.
This is what you need to know about aftermarket alternatives to OEM alternators.
- Output isn’t always sufficient. Some aftermarket alternators don’t generate enough power to handle the entire vehicle’s electrical load. The maximum output may be the same as the OEM version, however what about at engine idle. This is typically where the power is needed and many aftermarket options will fall short here. The vehicle will then draw power from the battery, thereby discharging the battery making it inoperable the next time you need to start your engine.
- They are notorious fuel wasters. Some aftermarket alternators are not designed to be energy efficient (OEM alternators are). A more efficient alternator uses less engine drive power to charge the battery and run the electrical system.
If you replace a high quality OEM alternator containing a high efficiency diode with a basic aftermarket alternator containing cheap diodes, you’ll probably see fuel efficiency drop by about 2%. It amounts to maybe $50 a year, which doesn’t sound like much. But when you consider that an OEM alternator may cost $50 more than an aftermarket alternator, the OEM pays for itself in 1 year with fuel savings, and lots more over the next several years of use.
- They are often loud and obnoxious. Aftermarket alternator manufacturers may use cheap roller bearings, and you can hear it when the engine is running. Cheaper bearings also have a shorter lifespan, so you’ll replace it again long before your OEM alternator.
OEM alternators are built for the real world
All OEM alternators are built to work in the real world, where your vehicles operate in rough, bumpy, vibrating conditions.
They’re built with features like:
- Chassis suspension systems, isolating alternators from sudden jolts that damage bearings.
- Gel-supported electrical connectors, protecting connectors from the elements and stopping them from shaking apart.
- Bracket designs limiting lateral movement and protecting moving parts.
- Rough working conditions lead to damage in every vehicle component, including the alternator.
Very few aftermarket alternators are protected from vibration as effectively as OEM alternators.
You won’t notice this sort of feature right away, but it will be the difference between buying another aftermarket alternator in 2 years or buying a new OEM alternator in 15.
Are OEM alternators worth buying? Absolutely. We think it’s the smartest financial move for businesses anywhere in the world.