Road Test: Volvo FM Electric

We spend a week working a battery-powered Volvo FM Electric - and the results might just surprise you! We were let loose with a battery-powered Volvo FM Electric tractor unit for a full week by the trusting souls at Volvo Trucks UK headquarters at Warwick. We're not sure if this was a mark of the confidence they have in us, or the confidence they have in the fool-proof qualities of their fully electric truck range.

We approached the week with a degree of trepidation because of the unique nature of the trial. We had a week-long use of a 15-tonne gross Volvo FE box body rigid back in 2021, which went surprisingly well; but taking to the road with a tractor unit pulling a range of different trailers and venturing further afield was taking things to another stage. We knew we could charge the truck from the 43 kW AC charging points in Broughton Transport's depot, as the three-phase power points are normally used to power the electric standby system on their fridge trailers.

Experience with the FE showed it would recharge overnight, but we were not sure if the same would apply with the bigger battery packs on the FM tractor. Fortunately, it worked in the same way as with the smaller rigid and the batteries were returned to 97% capacity in 8/9 hours, after being run down to as low as just 10% after a particularly busy day.

The high-capacity DC charging points that are starting to appear in a few locations, with up to 250 kW capacity, would completely recharge the FM batteries in two hours and bring it up to 80% charge in under 1.5 hours. While these type of charging points are very expensive to install, they can replenish over 50% of battery capacity in 45 minutes, making it possible recharge a truck that returns either to base or visits a charging point halfway through the driver's shift. Volvo claim a predicted range of around 200 miles (300+ km) and our experience shows this to be about right.

It's not enough for a lot of operations, but in this test we were able to keep busy both in the local area and keeping within a 50-mile radius of the depot. In addition, modern battery-electric vehicles can return power to the batteries while braking, as the electric motors become generators creating electricity while slowing the vehicle.

Range anxiety

Range is a big issue for all electric vehicles and it was the question almost everyone asked wherever we went with the Volvo FM Electric. The battery technology is evolving quickly and Volvo predict a steady increase in the available range of all their electric range.

The system uses 70% of the potential capacity of the batteries - as with mobile phone technology, 15% of the capacity at either end of the range is not used, leaving 378 kW of usable electric power. This is done to extend the life of the batteries, which is claimed to be in the region of 8/9 years, and this is improving rapidly. Volvo only really started the development of its electric range in 2017/18, and a lot of progress has been made in this relatively short time and the trucks are now in production.

The next generation of batteries will increase the range considerably. Volvo predict an increase in the order of 50% in the next couple of years and more again going forward.

Given the progress they have made in the last five years or so, we see little reason to doubt this. However, we don't see battery-electric as the only alternative power source for heavy trucks in the future: gas, hydrogen fuel cells, hydrogen-powered internal combustion engines and the modern generation of very low-emission diesel all have a part to play. But electric will certainly be one of them for specific applications and where it fits the bill, the early signs are the FM Electric and the other models in the range will do a very good job.

The very high initial cost of electric vehicles is a further issue as they are far more expensive to buy - something like three times the price of the equivalent diesel - so operators are going to need considerable incentives to make the change. The batteries are mounted in individual packs on the chassis. Each pack houses a series of trays with individual cells, each holding an electric charge.

This means as the packs age, there is a decline in efficiency - but tests have shown this is a very gradual process, rather than a total failure of the entire battery pack. While a proportion of the individual cells might have a reduced capacity, the rest continue to function effectively - unlike the first generation of electric cars, where the battery fails completely and the vehicle fails to operate. The system used in trucks by Volvo and other manufacturers mean the loss of potential range would be very gradual, allowing the truck to keep operating for as long as a decade.

Replacement of the batteries would be expensive, but it might not require a complete set of new batteries; possibly just replacement of one or two packs. Even then, used batteries can still have another life as a storage bank for electricity in depots and recharging sites.

Driving impressions

Apart from the FE rigid, we've had short spells behind the wheel of electrically powered heavy trucks on press events, but there is no substitute for going out and delivering a load with one. On our first day on the road with the FM Electric, we kept close to home - just to get used to the truck and understand how it worked.

It proved to be surprisingly effective, and later in the week we ventured out of Wiltshire and into the neighbouring counties of Somerset, Dorset and Oxfordshire. Driving the truck is simplicity itself; but even so, we took our time because of the unfamiliarity of the concept. Its absurdly easy to drive and you quickly gain confidence.

This is partly helped by the fact it is based upon the latest FM range, which are good trucks to drive regardless of the type of power unit. Once behind the wheel, everything is very familiar, but first you must switch off the power supply from the mains. The charging cable has a built-in battery condition monitor that shows the level of charge, and the tell-tale lights on the charger socket indicate if it is still charging or not.

Once the power is isolated, the cable is unplugged at both ends and stowed in the side locker and the truck is then ready for work - obviously after a conventional walk-around check is carried out. Turning the key activates the dashboard.

All looks normal save for the lack of a rev counter, plus diesel and AdBlue gauges. Turn the key a bit further and the drive system is activated; there is a slight whine as the compressor kicks in to restore pressure in the air tanks, but this soon dies off. Otherwise select forward or reverse via the normal I-Shift control next to the seat, press the accelerator, the electronic handbrake releases automatically and the truck starts moving.

But unlike any other FM, the is no noise whatsoever, save for a barely discernible whine from the electric motors. Coupling up to a laden trailer is completely effortless: just make use of the full air suspension to lower and raise the tractor unit and ease the truck back onto the kingpin. The lack of engine noise means it's not only possible to hear the jaws click on the coupling, but you can actually make out the twang of the return spring pulling the locking handle back into place!

Under control

Low-speed control is first rate: Volvo have developed a very sophisticated traction control system to both limit wheelspin and modulate the delivery of the high levels of power and torque produced as soon as the throttle is pressed.

We tended to select a lower gear than the one chosen automatically when shunting in a confined space, but this was probably more from habit with diesel trucks with automated gearboxes than any real need to improve control. As speed increases, I-Shift makes its first gearchange at about 25/30 mph, with another change into top at about 45 mph. But although the truck starts off in sixth seventh gear even at 40 tonnes or more, the high levels of power produced as soon as the motors start to turn mean it's very quick off the mark.

It will beat any conventional diesel away from the lights - even 750/770 bhp versions - because they must make at least two more shifts to get to the ratio the electric FM pulls away in. The lowest gear we saw the truck select was fourth, and that was for a fully laden start on about a 12% gradient - and even then, it pulled away without a murmur. There is no clutch to break the drive to the transmission: the three electric motors drive directly onto the input shaft of the gearbox, giving a seamless delivery of power.

It doesn't lose a lot of speed on most hills, although it does start to tail off on really steep gradients and the transmission will drop a gear or two to reduce the load on the electric motors; but it soon gains speed again as the hill eases. It climbed a local 12% gradient at 40 tonnes in ninth gear at about 25 mph, which is about on par with a 600+ bhp diesel - although it would be in a lower gear and wouldn't gain speed as quickly as the electric FM. The best way to drive the Volvo is to only use part throttle after pulling away from standstill, as flooring the pedal all the time is likely to provoke the traction control system which backs off the power.

This way, you achieve a better average speed. Approach roundabouts and junctions at a sensible pace and invariably you can take advantages of gaps in the traffic to keep moving. After a while, it becomes second nature and the whole experience is very relaxing.

The lack of noise and smoothness is uncanny; the driveline is so refined, and the transfer of power between the motors and drive wheels is silky smooth. The engineers have done a fantastic job.

Making power

The regeneration function is very interesting. Used properly, it will handle almost all the on-road braking.

It is operated by what would normally be the engine brake control with a diesel, via the lever on the steering column. It has multiple settings: firstly, it can be activated whenever the brake pedal is pressed, or alternately whenever the accelerator is released, with two levels of braking. It has similar braking power to a very effective gearbox retarder, but it will bring the truck to a near standstill.

The amount of power returned to the batteries depends on the amount of time it is applied, the weight of the outfit and the steepness on the downgrade. At full weight, descending the same long gradient that brought the truck down to ninth gear when ascending, returned 3% more power to the system. We found the best way to use the system on urban roads was to build up speed, lift right off and let the truck roll without power as much as possible, then apply the regenerative system progressively approaching junctions and roundabouts.

Probably the most interesting statistic was 24.8% of the total power used over the week was produced by the regenerative system - which means a quarter of the electricity used was generated by the truck itself.

Verdict

From a driver's perspective, we found the Volvo FM Electric a delight to drive and far better than we first imagined. The lack of noise is so relaxing and also highlights just how much noise an empty curtainsider trailer makes. While cruising at 50+ mph, it's possible to hear the muffled squeaks from the suspension bushes on rougher roads.

The overall effect is quite surprising: firstly slight irritation, then confusion because there is no engine noise, then mild amusement and very often appreciation of the benefits the truck brings. The truck attracted attention from everyone almost everywhere we went, and not just from the forklift drivers and warehouse staff - bosses came out from their offices and invariably asked the same questions. Is it fully electric?

The third answer always shocked everyone: well over GBP300,000, or roughly three times the cost of an equivalent diesel FM! This is one of the core issues for anyone contemplating the move to electric power. If society wants electric vehicles, it will have to pay a lot more for transport.

A tag-axle 6x2 will help in this respect, but the first one to go into service tares at 12,140 kg, which once again is a lot more than a diesel. But electric does work in principle. A lot more needs to change to make it a practical alternative, and we think there are many applications that are better served by other types of power.

But find the right application, secure your electricity at the right price with sufficient charging points, and then it makes perfect sense. We really enjoyed our time with the truck and are keen to try other versions. Probably the best experience was when at the big Amazon depot at Swindon, they have a strict no-idling rule; you must turn the engine off as soon as you stop at the gate and when opening the trailers doors to back on the bay.

Eventually they asked: "Why can't you switch off the engine?" We took huge delight in saying: "Because it doesn't have one!"