In recent years the widespread popularity of cubicle sweepers and lime dispensers on Irish farms has grown in line with expansion of the dairy herd.

Bigger herds and limited availability of labour has meant farmers are getting busier.

To help save time and physical strain, many have turned to increased mechanisation, such as cubicle sweepers and dispensers.

The rapid growth of electrification in all types of vehicles has filtered into more and more agricultural vehicles, particularly over the past two years.

We put the Bobman Super diesel and Super electric head to head to see if the electric machine proved a worthy option over its long standing diesel counterpart.

Not one to rest on its laurels, Danish manufacturer Bobman introduced an electric version of its cubicle sweeper and dispenser in 2020, some 20 years after it first began building such units.

Considering such machines are used for relatively short periods of time each day, we put a traditional diesel-powered unit head-to-head with its electric-powered counterpart on a farm in north Co Dublin last week.

What’s the difference?

Not only are both machines similar visually, but in build and dimensions too. The one and only difference is under the seat.

Essentially, the 10hp single-cylinder Hatz engine is swapped out for a sizeable 4kW electric motor and four 12v 65Ah/70Ah batteries (lead/lithium-ion).

Like the diesel engine, the electric motor is directly coupled with the hydraulic pump.

The 12V 70Ah battery and 13hp motor setup (left) and the 10hp Hatz diesel engine (right).

Instead of filling up the 5l diesel tank, the electric models are recharged by plugging the 13amp smart charger into the dash-mounted port. Bobman quotes charging times between three and four hours to charge the batteries from 20% to 100%.

The electric model we tested was fitted with traditional lead batteries although a lithium-ion battery option is now available.

The electric Bobman with the lithium-ion battery has a total hourly running cost of €1.58 while the diesel variants is €1.50.

One of the main advantages of the lithium battery over the standard lead option is a 30 minutes increased run time and the fact performance remains constant until batteries become critically low. Machines powered by lead batteries tend to lose performance gradually as charge drops.

The other main difference between the two methods of propulsion is routine maintenance.

The diesel Bobman will require its air filters to be blown out anywhere from once daily to once weekly depending on the material being applied and usage. As with any diesel engine, typical routine engine services such as oil and fuel filters still apply.

Both machines feature the same 75cm brush and 1m scraper.

On the other hand, and music to the ears of many, is the lack of maintenance with the electric machine. Aside from occasionally blowing down dust around the motor and changing the hydraulic filter every 200 hours, it’s just a matter of charge and go. Well, until the batteries start to fade and run times reduce. After 1,500 charge cycles or approx five years Bobman recommend replacing the batteries.

As standard, Irish spec machines are fitted with selectable 1WD and 3WD. The rear 1WD leaves for a tigther turning circle.

Donal Callery, Swords, Co Dublin

Donal Callery, Swords, Co Dublin

Milking 110 cows as a new entrant last year, Donal Callery’s herd is being bumped up to 350 cows for the coming year. With such a jump in numbers and further expansion planned, efficiency and time management were given key priority.

“Based on hearing good reports around the country, we decided last autumn that we wanted to invest in a self-propelled cubicle sweeper and lime dispenser.

“We called Moreway and they brought us out both a diesel and an electric demonstration machine.

“We liked both machines, but at the time the electric demo unit was the only such version in the country. We fell in love with how quiet it was, and based on a recommendation from the team at Moreway, we decided to go with it.

“To date, we’ve been delighted with the decision. We have two sheds side by side with 450 cubicles. It takes 10 minutes to brush down and lime all the cubicles. Last year we milked 110 cows and it took one man almost an hour daily to clean down and bed the cubicles. When the machine returns to the shed where its stored, we load it again with lime and put it on charge. Its maintenance is limited to a handful of grease points”.

John Coakley, Maynooth, Co Kildare

John Coakley, Maynooth, Co Kildare

Milking 100 cows near Maynooth, John and his son John junior made the move to a diesel-powered Bobman Super self-propelled cubicle sweeper and lime dispenser last November.

“The Bobman Super has been doing a great job for us. We could never clean the cubicles as clean with a hand-held scraper.

“We went for the diesel option as it was proven and the cheaper option. The machine is used to clean and bed 100 cubicles, and scrape a small area at the top of the shed twice daily, seven days each week.

“It typically clocks up approximately four hours work each week and consumes four litres of diesel, so one litre/hour.

“We clean and bed the cubicles when the cows aren’t in the shed, so the noise of the diesel engine isn’t an issue for us. However, if we were doing this with the cows in the shed, I think the electric version would be a better option as it’s very quiet.

“In terms of maintenance, we blow out the air filter once per week and grease several points at the same interval.”

The day-to-day running costs of each system will vary massively from farm to farm, depending on farm size, layout and the demands placed on the machine etc.

Bobman says a lead battery configuration on full charge will typically last from 45 minutes to one hour, while a lithium-ion battery on full charge will last from one hour and 15 to one hour and 20 minutes.

Assuming an electricity cost of 30c/KWh (including taxes, PSO levy and standing charges etc), it will cost approximately €1.01 to fully charge (0-100%) the electric machine, with the lead battery and €0.94 to charge the machine fitted with the lithium-ion battery.

Bobman says the optimum life of both battery types is 1,500 charge cycles or five years approximately. While the batteries are expected to run at full power for much longer than five years, working duration steadily decreases.

Both the charge level and battery run hours are shown on the display.

The replacement cost of the four lead batteries is €700 plus VAT. If one battery fails for some reason, they can be individually replaced at a cost of €180 plus VAT.

The lithium-ion batteries bring about longer running times, but at an increased cost. The four batteries total €1,000 plus VAT, and again can be individually changed if need be. It is also possible to upgrade a machine that has previously used lead batteries to lithium-ion batteries, with just a new configuration to be programmed into the charger.

The smart charger simply plugs into the dash mounted connection.

Meanwhile, as stated by John, the diesel engine is consuming an average of one litre of diesel per hour. Based on agricultural diesel at today’s average cost of 92c/l including VAT, its running costs will be 92c/hr.

In terms of service intervals, the diesel-powered machine requires a service every 200 hours. This includes a change of air, hydraulic and diesel filters and engine oil replacement. The materials for this service come to a cost of €115.95 including VAT. Meanwhile, the electric-powered machine only requires a change of hydraulic filter after every 200 hours, which comes at a cost of €14.99 including VAT.

It takes the electric models between three and four hours to charge from 0% to 100%.

In terms of overall buying costs as seen in Table 2, the diesel-powered machine is the cheapest at €19,700 including VAT.

Coming in a little over €2,500 more is the lead battery machine, followed by the lithium-ion battery-powered unit which trends €2,900 above the diesel equivalent.

By using the hand throttle on the diesel machine, the throw distance of the lime could be varied independent of forward speed. However, the electric machine only had the ability to spin its hydraulic motors at one of two speeds (low or high). A dash-mounted switch was used to select between low and high, with the switch also having an impact on forward speed through restricting oil flow. Happy with the spread distance in low, we only found the need to change into the higher range when travelling from the store to the slatted shed for extra forward speed.

Overall, we found the electric version to be a lot smoother in operation, while offering full power instantaneously.

Once the diesel engine was started, it gave off a slight vibration and the engine had to be revved up to offer this same power the battery version had instantly.

The engine air filter willl need to be blew out daily or weekly depending on how dusty the material is.

The quieter and emissions-free operation of the electric version means it’s ideal for working indoors around livestock, and would be our machine of choice. The success of electric power in this instance is largely down to the fact these machines are only used for short periods of time each day. However, for those looking to keep initial outlay to a minimum, the diesel version at €2,900 less is well capable of doing the same job.