Choosing the Right Inverter and Wiring Harness is Critical

A few considerations when selecting a DC-AC power inverter for your tractor include inverter type, power rating, and the correct wiring harness. Cutting corners on quality and installation can result in catastrophic failures that no fleet or driver would want to experience.

Burned truck from a faulty inverter installation


Burned truck from a faulty inverter installation

Inverter Basics:

There are two basic types of inverters: pure sine wave and modified sine wave:

Pure sine wave is the same electricity that you receive from your utility company. Some devices such as medical equipment, electric tools with motors, and charging devices require utility-quality power that comes from a pure sine wave inverter. Most other items such as TV’s and microwaves can be operated from a modified sine wave inverter.

While most inverters are very efficient, they lose power capacity while converting from 12 volts DC to 110 volts AC. Fleets should provide drivers with a list of approved devices and power requirements so drivers can ensure that they are protecting the truck as well as meeting their power needs. Trouble can start when an operator tries to run all of their devices at once and does not succeed.

Inverters have their limits and consume a lot more power than you think. For example, a 1500-watt inverter with full output will draw roughly 150 DC amps per hour from the batteries. With that amount of current, it would not take long to run down the vehicle batteries. Inverters should be used for short time periods to power devices that cannot be powered efficiently with DC power. The high current that an inverter draws means that it must be connected directly to the vehicle batteries. It cannot be controlled by the vehicle’s low voltage disconnect (LVD) system.

It is also important to make sure the correct wiring harness is being used. Cables that are the right length and cable size allow for optimal power transfer from the batteries to the inverter.

Tips for Selecting and Installing the Right Wiring Harness:

  1. When routing the cables, they must be kept away from heat sources and moving parts. Un-noticed damage to the cables can result in loss of function and a highly undesirable outcome to the vehicle.
  2. Wiring harness kits should include a properly rated fuse cube so that the entire circuit is protected.
  3. Kits should also have ground wire for the inverter case, wire ties for secure fastening, and wires should be encased in color matching and convoluted tubing to provide added protection.
  4. Terminal ends should be made of tin-plated copper with the correct hole size for the cable and it should be fused to the cable with a dual-wall heat shrink tube and glue, which provides excellent protection from corrosion.
  5. In the cab, use plastic dome nuts to protect the cable installation as it goes through the metal of the cab.

Inverter and Custom Wiring Harnesses:

Purkeys produces wiring harnesses and inverters with all of these features built-in. Our inverters include electronic controllers that operate as timer or LVD. The controller gives the driver comforts of home for a reasonable period while protecting the vehicle batteries from deep discharge. We only use welding cable to provide the greatest flexibility for routing the cable.

To learn more about our wiring harnesses and power inverters, contact one of our technical experts today or visit our inverter product pages.

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