13 Jan Unusual: German electric grader with a Dutch touch
Published on bouwmachines.nl | Matthijs Verhagen | 19 Dec 2024
Photos: Matthijs Verhagen
At Bauma in 2022, the German grader manufacturer HBM-Nobas surprised visitors with a fully electric grader: the 16-tonne BG120 TA-E. Graders represent a small market in our country, so electric graders are even more of a rarity. Drenth Groep in Emmen (Drenthe) has now had a year of experience with the electric HBM. How is it performing in practice?
Six models
Among the major global brands active in graders, there is one smaller independent manufacturer. The German company HBM-Nobas was formed in the early 1990s through a merger between two machinery builders, and since then it has been a subsidiary within the large German construction group GP Günter Papenburg AG. The machinery manufacturing division exclusively produces graders in Nordhausen, Germany.
In the past, graders were also built for Terex, but now all machines leave the factory under the company's own brand name. There are six models, ranging from 7 to 23 tonnes. HBM proved that a smaller manufacturer can adapt quickly at Bauma 2022. At the time, the brand introduced two electric graders; one low-profile machine for use in mining tunnels and the BG120 TA-E in this field test. HBM-Nobas presents and supplies these graders as factory-electric.
A Dutch touch
In fact, the machines currently in operation have been converted from diesel to electric power on the manufacturer’s instructions. This development and conversion were carried out by a Norwegian partner, Nullutslipp AS.
There also appears to be a Dutch touch behind the scenes: the electrical components come from the Dutch conversion specialist New Electric in Breukelen, which also electrifies other road construction machinery. This is very practical for Dutch buyers. Drenth Groep is now also assisted by this company in servicing the electrical components, whilst Van Der Spek Vianen is the importer and supplier of the HBM.
All the components are located on the right-hand side of the machine. From hydraulic oil filters to inverters and the main fuse.
Operator Remco Beuving is out on the road every day with the grader. The electric HBM is now his regular machine, whereas he previously worked as a stand-in on various graders within the Drenth Group. With a range of Deere, Case and HBM graders, Drenth is one of the major players in this sector. After a year and around 700 operating hours, Beuving certainly sees the benefits of electric operation, although he remains critical of peripheral issues such as limited charging infrastructure.
Noise level
Particularly the low noise level is something he experiences in practice as a major advantage. “In the summer I work with the door open and even then the cab is still quiet. You can understand each other easily if I'm discussing something or have someone on the phone.” Moreover, because of that quietness, Beuving can hear what is happening in front of or beside the bulldozer blade, even in places where he cannot see it. “When I am fine-grading next to a concrete kerb or stretcher course, you hear it immediately if you touch it lightly and I can correct that straight away. I also hear the material rolling in front of the blade, so you know better how much is still in front of the blade.”
Despite the fact that the machine spends virtually the whole day travelling back and forth – which usually requires a lot of energy – the installed battery capacity of 325 kWh proves, in practice, to be sufficient to get through a day. “It depends, of course, on the conditions and how much material you need to move. But almost without fail, I still have plenty of battery capacity left at the end of a full day’s work. Recently I had a job in loose sand, which is naturally very demanding, and in that case the battery can run flat after five or six hours. But that sort of thing really is rare, and normally I can easily work for eight to ten hours.”
Adjust the procedure
Beuving often completes a job in one or a few days. Constantly changing work locations made it difficult at the start to establish a routine for charging. “That’s why we now have our own fast charger at a client’s site where we do a lot of work.” This company is located close to the driver’s home, making it a sensible choice from a logistical point of view too.
However, the working method was adapted to suit the zero-emission machine. Normally, Drenth outsources transport, but this proved impractical when used in conjunction with the electric machine. To ensure the charging process runs smoothly, Beuving transports the machine himself in his own semi-low-loader lorry to the job sites across the country and back to the fast charger in the evening. On his return, he connects the machine to the charger himself. The following morning, the machine is fully charged and ready for the next job.
The grader is fitted with a CCS2 charging point at the rear. When connected to a fast charger, the battery is fully charged in just under 3 hours. The built-in charger can deliver a maximum charge of 40 kW.
“I can monitor the charging via an app. If I have a job lasting several days, the machine can also charge from a temporary site supply. I limit the charging amperage myself, so that the battery trickle-charges as slowly as necessary. It doesn't need to be fast, as long as it's full by the next day. That's better for the battery and puts less strain on the power supply. Charging on the road at a rapid charger is also possible, though sometimes the charger and battery don't yet communicate properly.”
The concept works
Charging and the fact that there are sometimes some stoppages due to a breakdown are things that come with a new development, Beuving believes. Because the machine performs well in daily work and he enjoys working with it, he takes that in his stride. “The concept works, I'm just telling the complete and honest story. That side belongs to it too.” In terms of tractive power, speed and method of operation, including the options for 3D GPS, the machine is no different from any other HBM grader. In this case, Drenth chose Leica.
The electric BG120 TA-E is based on the latest HBM BG120TA-7. Compared to the prototype at Bauma, Drenth’s machine features a newer cab. Whilst it has slightly less storage space, it offers a better view of the dozer blade, as HBM has moved the door latch from the bottom to the centre of the glass door. A small detail, but a very important one, as the latch is no longer in the line of sight to the dozer blade. In terms of basic technology, the grader is practically identical to the diesel version.
Engine
HBM replaced the 149pk Perkins diesel engine with a Siemens electric motor of exactly the same power output, delivering 110 kW. The drivetrain, controls and valve block remain unchanged. The electric motor transmits its power to the six-speed ZF powershift gearbox with torque converter to drive the four rear wheels. The hydraulic pump is also connected to this transmission. It supplies oil to the electronically controlled valve block for the hydraulic functions and the hydraulic drive to the front wheels. This means the grader is driven on all six wheels.
There is no engine, but a large battery pack (325 kWh, 350 volts) fills the space under the bonnet. The 110 kW Siemens electric motor is built in beneath the battery.
To minimise rutting, the Drenth machine is fitted with wide (560/60R22.5) tyres. It is also, of course, fitted with a ripper at the rear. One difference compared with the diesel version is its kerb weight. Compared with the standard 14 tonnes, this electric version weighs 16 tonnes due to the addition of the battery pack.
Operation
When it comes to handling, too, the similarities are what stand out. Just like with the diesel version, there’s an accelerator pedal that lets you control the engine revs yourself. As soon as you turn the ignition on, the electric motor also idles. “If your blade is full and you feel it’s getting a bit heavier, you simply give it a bit more throttle, just like with a diesel,” The electric motor will then rev up a bit,” explains the operator. In the operator’s experience, the feel of the controls is no different from that of HBM’s diesel versions. This grader also has the identical electronically controlled valve block under the bonnet.
The HBM features both joystick controls and a traditional steering wheel. The dashboard looks a little dated and obstructs the view. On the right-hand side of the A-pillar are the displays for the front-view camera, the reversing camera and the electrical system.
The machine is equipped with joystick controls. At the same time, there is still a steering wheel in the cab. “Personally, I quite like that for road transport. Not all brands still have that,” explains Beuving. Specifically for road transport, the grader also has cameras on the left and right of the dozer blade, due to its length.
Certainty
All in all, HBM offers a unique machine with its electric grader. Moreover, buying directly from an established manufacturer provides peace of mind: the design has been tried and tested, and you have a single point of contact for the warranty.
That said, you can tell that, beneath the surface, the engine has not been developed from the ground up as a purely electric powertrain. After all, the powertrain – which still features a complex transmission with a torque converter – could be more efficient. In practice, however, the range does not tend to be a limiting factor. It therefore seems a sensible choice to build on the existing design, retaining the same power output whilst maintaining the proven handling and performance. Mission accomplished.
