26 Dossier | Liebherr piling machines July/August 2026 | E-Mobility Engineering The diesel motor achieves between 1600 to 1800 rpm, whereas the electric motor can run from 500 to 2300. However, Liebherr has introduced an innovative frequency converter to maintain a consistent 1000 rpm at all times. “The diesel engine is always changing, running at more or less revolutions per minute. So, having a motor that can run at one speed has significant advantages,” says Mewes. “It allows also to have a constant speed of the hydraulic motor, constant hydraulic pressure, constant hydraulic oil flow and constant speed of the winches, so that’s far better for operation. “As it is a frequency-converted motor, we can adjust the frequency and control the voltage, and this is the best way to control the speed of our motor. All other components in the upper carrier – the cooling systems and so on – are running with direct current of 700 V, and we have another converter to deliver 24 V for the onboard electrics. We’re using the same systems across the board on all of the unplugged machines – the carrier is the same as we use for the LB 30 drilling rig unplugged, the piling rig unplugged and the crawler crane, and we use a lot of the same components across these machines.” Charging and operation All of the Liebherr range of deep foundation machines provide the option for plugged-in or unplugged operation, making them quite unusual in the EV space. Their relatively static operation allows on-site power to provide direct recharging while in operation – much in the same way as a mobile phone can still be used while it is plugged into a charging socket. The electricity on most job sites is between 380 to 400 V, which Liebherr converts into DC of around 700 V to charge the batteries. The system uses off-the-shelf highperformance Li-ion nickel manganese units from Akasol Batteries, which promise a life of 10 years or 4000 cycles. The standard unit provides 300 kWh of storage, with options for 400 or 600 kWh, and charging can be carried out at 400 V AC, with a maximum of 20 kW at 32 A, 40 kW at 63 A and 80 kW with 125 A. The 300, 400 and 600 kWh batteries provide Construction in the centre of cities is under increasing demand to reduce emissions All of the Liebherr range of deep foundation machines provide the option for plugged-in or unplugged operation
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