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Understanding the Differences Between Diesel and Electric APUs for Trucks

As trucking technology advances, the debate between diesel and electric Auxiliary Power Units (APUs) continues to gain traction. Both types of APUs offer unique benefits and drawbacks, making it essential for truck owners and fleet managers to understand their differences. This blog post delves into the history, cost, key players, and maintenance aspects of diesel and electric APUs, providing a comprehensive comparison to help you make an informed decision.

History of Diesel and Electric APUs

1. Diesel APUs

Diesel APUs have been around for several decades, emerging as a solution to the problem of truck idling. Initially, truck drivers had to keep their engines running to power the cabin's HVAC system and electrical devices during rest periods. This led to excessive fuel consumption and engine wear. Diesel APUs were introduced to provide an alternative power source, running on diesel fuel but consuming much less than the main engine. These units have since become a staple in the trucking industry due to their reliability and established technology.

2. Electric APUs

Electric APUs are a more recent innovation, gaining popularity over the past decade. Early electric APUs utilized Absorbent Glass Mat (AGM) batteries, which provided a cleaner and more efficient power source compared to diesel units. However, the true game-changer came with the advent of lithium-ion batteries. Lithium batteries offered higher energy density, longer life cycles, and reduced weight, making electric APUs even more attractive. As environmental concerns and fuel costs continue to rise, the shift towards electric APUs is accelerating.

Price Comparison

1. Diesel APUs

Diesel APU

Diesel APUs generally have a similar and slightly higher upfront cost compared to electric APUs. Prices typically range from $10,000 to $15,000, depending on the brand and specific features. However, the ongoing cost of diesel fuel and regular maintenance can add up over time, impacting the total cost of ownership.

2. Electric APUs

Electric APUs, particularly those using lithium-ion batteries, range from $5,500 to $15,000. Electric APUs can offer significant savings in fuel and maintenance expenses. The total cost of ownership can be lower in the long run due to reduced operational costs.

Key Players in the Market

1. Diesel APUs

Thermo King: A leading manufacturer known for reliable and efficient diesel APUs.

Carrier: Another major player offering durable and high-performance diesel APUs.

RigMaster Power: Provides a range of diesel APUs with a focus on fuel efficiency and reliability.

2. Electric APUs

Polar Fox APU: Specializes in electric APUs with advanced lithium batteries, offering quick installation and multiple design options.

DClimate: Known for their electric APUs utilizing AGM batteries, providing a green alternative to diesel.

Bergstrom: Offers electric APUs with advanced battery management systems for optimal performance and efficiency.

Maintenance Considerations

1. Diesel APUs

Diesel APUs require regular maintenance similar to that of a small engine. This includes oil changes, fuel filter replacements, and periodic inspections. While diesel APUs are generally robust, they can be prone to issues such as fuel injector clogs and exhaust system problems if not properly maintained.

2. Electric APUs

Electric APUs, especially those with lithium-ion batteries, require significantly less maintenance. There are no oil changes or fuel filters to worry about, and the primary maintenance involves checking the battery health and ensuring the electrical connections are secure. Lithium-ion batteries have a longer lifespan and more charge cycles compared to AGM batteries, reducing the frequency of replacements.

Performance and Efficiency

1. Diesel APUs

Diesel APUs are highly efficient in terms of fuel consumption compared to idling the main engine. They can provide consistent power for extended periods and are effective in extreme weather conditions. However, they do produce emissions and can be noisy, which might not be ideal for all situations.

2. Electric APUs

Electric APUs are virtually silent and produce zero emissions, making them an environmentally friendly option. They are particularly effective in regions with strict anti-idling regulations. Lithium-ion battery-based APUs offer superior energy efficiency and longer runtimes compared to AGM batteries.

Polar Fox Electric APUs: A Superior Choice

Polar Fox stands out in the electric APU market with its advanced lithium battery technology. These APUs are designed for quick installation, minimizing downtime and getting you back on the road faster. The starting price of $5,500 makes them a competitive option, especially considering their long-term cost savings and environmental benefits.

Key Features:

Advanced Battery Management System (BMS): Ensures optimal battery performance and safety.

Quick Installation: Engineered for easy and fast installation.

Multiple Designs and Capacities: Tailored to meet various customer needs.

Competitive Pricing: Starting at $5,500, offering excellent value for money.


Choosing between diesel and electric APUs for your semi truck depends on your specific needs and priorities. Polar Fox Electric APUs, with their advanced lithium batteries and user-friendly design, present a compelling option for modern truckers looking to optimize their operations.

For more information and to explore our range of electric APUs, visit Polar Fox APU.

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