Blackburn Energy has developed an on-board charging system for heavy electrical loads such as battery-powered HVAC units and liftgates. Using a 200-amp alternator driven from the truck’s driveshaft, the RelGen system can eliminate idling for charging purposes while charging auxiliary batteries three times faster than a standard engine-mounted alternator, according to the company.

Blackburn’s RelGen uses a high-efficiency 200-amp alternator mounted on the inside of the frame rail just behind the transmission. It is driven by the truck’s driveshaft through a specially designed center bearing. The alternator and the drive mechanism are protected from the elements by a stainless steel cover and powder coated steel mounting plates. 

CEO and founder Andrew Amigo says there are several advantages to drawing on a kinetic power source other than the engine.

• At highway speeds, the drive shaft turns faster than the alternator drive on the engine — thus more energy can be captured.

• The mid-ship position places the alternator closer to the batteries, shortening the cable run and minimizing voltage drop.

• To match the output of the RelGen system, truck owners would need to upgrade the stock alternator and re-cable the charging system to accommodate the higher amperage.

“For the same price as upgrading the alternator and re-cabling the entire truck, you can install RelGen Hybrid Charging and get the maximum performance from your HVAC system or liftgate batteries,” Amigo says.

Powering Liftgates and Truck HVAC

To validate its claims, Blackburn Energy commissioned the Department of Mechanical Engineering at the University of Massachusetts–Lowell to verify the performance of the RelGen technology. Researchers found that with the truck’s starting batteries and alternator completely disconnected from the RelGen and its battery load, in a liftgate application, the battery state of charge never dropped below 80% at the end of the day over a 30-day period. Based on eliminating idling to keep the liftgate batteries charged, researchers estimated fuel savings alone would provide a payback in less than a year.

Evaluations with an electric HVAC system showed RelGen could fully recharge a depleted four-battery AGM pack after less than four hours of driving — roughly half the time it takes for a standard factory-installed alternator to charge the hotel-load batteries.

With a dedicated hotel-load battery pack, there’s no need to maintain a reserve charge for starting, so it can provide longer run times for the HVAC system.

The system is also available in a hybrid configuration that charges only when the truck is coasting or braking to produce zero-emissions energy for the batteries. That setup comes with a telematics unit that records times, locations, and duration of the charging events for carbon credit reporting.

For fleets considering an alternator upgrade to support electric HVAC or liftgate charging, Blackburn Energy says RelGen is a more cost-effective option from the start, and it provides greater charging capacity than typical high-output alternator configuration — while reducing charging related idling to charge batteries. It can be installed by skilled mechanics in about four hours or at dealer mod shops, according to the company.