Mack MD Electric enters production

Mack Trucks has begun adding battery-electric medium-duty models to its MD series of diesel trucks, which has been sold since 2020.

At a demonstration staged at the Sonoma Raceway in northern California, company executives said Mack’s MD Electric trucks entered production in October and will begin appearing at dealerships early next year.

Class 6 and 7 MD-E trucks use a Sea Electric powertrain consisting of a 260-continuous-horsepower motor, two or three lithium-ion batteries and controllers operating at 400 volts, said George Fotopoulos, vice president of Mack’s E Mobility division. Ranges are 140 or 230 miles, enough for the vast majority of routes that midrange trucks cover, studies show.

The E models also get the same Meritor front and rear axles used in diesel models. Motors are separate from the axle differentials. Cabs and chassis, complete with air brakes, are likewise taken from the diesels with changes limited to what’s needed to support electric propulsion, Fotopoulos said.

Subscription

Because electric trucks cost about twice as much as diesels, Fotopoulos said the company is setting up a “subscription” finance service, called Mack ElectriFi, to ease the monetary side of acquisition.

ElectriFi will lend or lease charging stations and other infrastructure needed to “fuel” the trucks when they’re returned from their routes. It also will assist buyers in dealing with electric utilities to supply sufficient power and/or in installing solar panels and wind turbines to generate their own power.

In addition, Mack is preparing dealers to support the e-trucks by establishing standards for special tools, parts, equipment and training. Under ElectriFi, operators can obtain all-inclusive maintenance service for varying terms. Monthly payments are based on miles run. The per-mile charge gets lower as miles increase, he said, and agreements can be extended or ended at the end of terms.

There is no minimum number of MD-Es required to set up an ElectriFi subscription, Fotopoulos said, adding that “just one truck is enough.” He expects fleets to ease into the e-truck world with orders for twos and threes. News reports say that consumer interest in electric cars has flattened, but “there is huge interest” in electric trucks from fleets, Fotopoulos added.

The drive

Two MD-Es were available for brief drives around the raceway’s hilly, curvy road course to show off the e-truck’s power and ease of driving. The trucks had no bodies or loads, which allowed close inspections of the electric powertrains mounted between frame rails but limited realistic driving impressions.

Still, it was obvious that the MD Electric is quick and quiet. That’s true of most e-trucks, as an electric motor makes strong torque right from the start, and it works quietly. A diesel has to rev up to develop its maximum power and torque and makes noise doing it.

That drowns out most rattles and squeaks that the driver now hears in an electric truck. This MD-E’s cab did rattle and squeak a little, which might or might not bother drivers. I think most guys and gals would simply appreciate the overall quietness.

The Mack MD-E seemed to handle about the same as the diesel versions I’d driven a few months earlier. The cab sits high, and the general feel is close to that of a heavy truck, but without a Class 8’s bulk. A selector offers push buttons for drive, neutral and reverse.

The electric motor directly turns a driveshaft connected to the rear axle’s differential, and there is no transmission, aka “gearbox,” between them. So the motor winds out from zero to 70 mph, according to Mack’s specs, driving through a short propeller shaft to a standard differential housing 5.73:1 gears. I managed to get up to 45 mph or so on straightaways before slowing for turns.

Accessories and features

Of course the E’s instruments are somewhat different. There are no engine condition gauges, and the diesel’s tachometer is replaced by an E’s big dial that shows how much battery energy is either being consumed or replaced during braking or regeneration.

I frequently pressed on the brake pedal or just backed off from the accelerator while approaching curves and turns and watched the needle swing to the right, indicating charging. Three regen levels can be set by a twist switch on a stalk protruding from the steering column. Retarding at Level 3 is strong and should save a lot of wear on brake linings.

All of Mack’s accessories are electrically driven. That includes a power steering pump and A/C compressor, both under the tilting hood. And the air compressor, down on the curb-side frame rail, operates the brakes and air bags under the cab and the rear axle’s suspension. It can barely be heard from inside the cab, but its chugging sound is apparent from outside.

‘Off-the-shelf’

The Sea Electric powertrain is “off-the-shelf” and is better sized for medium-duty tasks than any powertrain Mack might have obtained from Volvo Group, its corporate parent in Europe, Fotopoulos said. In that sense, the MD-Es are like the diesel MDs, which use a Cummins-Allison powertrain rather than something sourced from within the corporation.

The MD-E’s beefy motor is hung several feet ahead of the rear axle, a standard Meritor product rated at 17,000 pounds on the Class 6 version and 21,000 on the Class 7, just like on the diesel MD. The motor makes as much as 1,850 lb-ft, but torque is electronically limited, especially during starts from a dead stop.

Farther forward in the chassis are a pair of electronic controllers and two battery packs, all mounted between the frame rails and connected by hefty orange-colored high-voltage cables. A couple of black rubber hoses carry liquid coolant between the motor and a saddle-mounted heat exchanger with two electric fans.

The charging port is on the left side, below and slightly to the rear of the cab. It supports standard AC charging, which can take as long as nine hours, and fast DC charging, which can be done in under two hours. Charging infrastructure is a matter for fleets and dealer shops, and the ElectriFi plan can offer assistance for that, Fotopoulos said.

One thing visually setting an MD-E apart from its diesel siblings is its bulldog hood ornament and badges being copper-colored rather than chrome. Because the two MD types otherwise look much alike, you’ll know the e-versions by this copper hue. LL

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