Truck Component

Idle Free Electrified APU (battery-powered)

Idle Free Systems · Apu · Battery-electric APU

Class 8 In production

Apu

Manufacturer

Idle Free Systems

What this component does

Idle Free Electric APU is a battery-electric alternative to diesel APUs — uses a large auxiliary battery pack (charged while the truck is driving) to power cab heating, cooling, and electrical loads when parked, with zero diesel consumption. Zero emissions = best California ACT compliance among APU options. Limited duration: typical 8-10 hours of operation before battery depletes. Best for drivers who park at shippers or truckstops with plug-in availability for recharging.

Specifications

Manufacturer: Idle Free Systems
Category: Apu
Subtype: Battery-electric APU
Truck class: Class 8
Production: 2010–present
Applications: Sleeper cab — battery-electric heating/cooling/power (no diesel)

Design and engineering

Lithium-ion battery pack (typically 12-15 kWh) mounted in chassis. Inverter for 110V output. Electric A/C compressor. Optional electric bunk heater or diesel-fired heater for cold-weather operation. Charges from main alternator while driving + optional plug-in 110V.

Generations

Idle Free Original (2010–2018)
Lead-acid battery era.
Idle Free Lithium (2019–present)
Lithium-ion battery pack — longer life, lighter weight.

Reliability and longevity

Lithium-ion battery typically lasts 5-8 years before degradation. Newer than diesel APUs — less long-term data.

Common problems

Limited duration vs diesel APU (8-10 hours vs unlimited with diesel + tank). Cold-weather performance limited (battery + electric heat consume more energy in winter). Battery replacement is expensive ($3K-6K).

Maintenance schedule

Battery state-of-charge check annually. Cooling system PM. Inverter check.

Pros and cons

Pros

✓Zero emissions — best CA ACT compliance
✓No diesel consumption
✓No engine wear (no moving parts beyond compressor)
✓Quieter operation than diesel

Cons

!Limited duration (8-10 hours)
!Battery replacement expensive at end of life
!Cold-weather performance gap vs diesel
!Requires plug-in for full-shift recharge

Trucks that use this component

Other Apu components

Frequently Asked Questions

What is an APU?

APU (Auxiliary Power Unit) is a small auxiliary engine or battery system mounted on a Class 8 sleeper-cab tractor that provides cab heating, air conditioning, and 110V electrical power without running the truck's main engine. Idle Free Electric APU is a battery-electric alternative to diesel APUs — uses a large auxiliary battery pack (charged while the truck is driving) to power cab heating, cooling, and electrical loads when parked, with zero diesel consumption. Zero emissions = best California ACT compliance among APU options. Limited duration: typical 8-10 hours of

How much does an APU save in fuel?

A diesel main engine consumes 1.5-2.5 gallons per hour at idle. A diesel APU consumes 0.2-0.4 gallons per hour — saving 1.5-2 gal/hour. At \$3.50/gallon diesel and 1,500-2,000 hours of annual idle time, an APU saves $5,250-\$14,000 per year per truck. Payback period: 8-24 months depending on usage. Electric APUs save additional fuel because they consume zero diesel during operation (battery is charged while driving).

Is an APU required by law?

No — APUs are not federally required. However: most US states have anti-idling regulations limiting how long a truck can idle its main engine while parked (typical limit 5-30 minutes depending on state). California, Texas, New York have the strictest rules. APUs provide the cab climate control that anti-idling rules would otherwise eliminate. Many fleets and owner-operators consider APUs essentially mandatory for over-the-road sleeper-cab operations.

How much does an APU cost?

New diesel APU (Thermo King TriPac, Carrier ComfortPro): \$9,000-\$13,000 installed. New battery-electric APU (Idle Free, EV-eAUT factory-fit): \$8,000-\$15,000 — slightly cheaper now that battery costs have come down. Diesel-fired bunk heater (Espar Airtronic D2 — heat only, no A/C): \$1,500-\$2,500. Used APUs (5-year-old): 40-55% of original price. Theft is a recurring fleet problem — APUs are easy to steal from parked trucks and have a strong used market.

How long does an APU last?

Diesel APU service life: 12,000-15,000 operating hours before major overhaul. Battery-electric APU: 5-8 years before battery degradation requires replacement ($3,000-$6,000). At 1,500-2,000 hours per year, diesel APUs last 6-10 years before major service; electric APUs last 5-8 years before battery replacement. Both require regular PM.

Diesel APU vs electric APU?

Diesel APU (TriPac, ComfortPro, RigMaster): Unlimited duration, works in any climate, mature technology. Drawbacks: EPA Tier 4 emissions complexity, \$0.20-0.40/hour diesel cost, ~400 lb weight, theft target. Electric APU (Idle Free Lithium, OEM factory-fit): Zero emissions, zero fuel cost, quieter, lower maintenance. Drawbacks: 8-10 hour duration, cold-weather range limits, battery replacement expensive at end-of-life, requires depot 110V/3-phase for full recharge. California ACT mandates and emissions trends favor electric for long-term fleet planning.

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Idle Free Electrified APU (battery-powered)

What this component does

Pros

Cons

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Frequently Asked Questions

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