Power sources: electric, gas, diesel, hydrogen

The power source determines not only range and power, but also where the truck can be used legally and safely — especially indoors, where exhaust and particulates become a workplace-health issue.

The limit value for diesel exhaust particulates in workplace air is measured as elemental carbon (EC) and was tightened to 5 µg/m³ as of 1 January 2025 (previously 10 µg/m³). In practice, this low limit means a diesel forklift cannot be used indoors without exceeding it. Always look up the current limit value in the Danish Working Environment Authority's (Arbejdstilsynet) list of limit values.

• 01Gas (LPG): can be used, but requires ventilation indoors because of the exhaust.
• 02Electric (lead-acid or Li-ion battery): well suited to indoor use; no exhaust. Charging stations require space and ventilation according to the supplier's instructions.
• 03Hydrogen (fuel cell): emission-free in operation (only water vapour) and suitable indoors.

The traditional traction battery is an open lead accumulator with liquid sulphuric acid. It is operationally safe, but involves two serious risks that the driver must handle during charging and replacement:

• 01Hydrogen evolution: during charging — particularly towards the end — the battery emits hydrogen. Hydrogen is very light and forms a flammable/explosive mixture from approximately 4 vol-% in air. Therefore the charging location must be well ventilated, and open flames, sparks and smoking are prohibited.
• 02Caustic acid: the electrolyte is sulphuric acid, which causes severe burns to skin and eyes. When working with batteries, acid-resistant gloves and eye protection are used, and access to eyewash/emergency showers must be nearby.
• 03Short circuit and arc: the battery can deliver very high current; a tool dropped across the terminals creates an arc and burning. Avoid metal objects over the battery.

Lithium-ion batteries charge quickly, require no water top-up and do not emit hydrogen during normal charging. However, the main risk is thermal runaway: a fault, overheating or mechanical damage can start a self-reinforcing reaction with intense heat, flammable/toxic gases and a fire that is difficult to extinguish.

• 01Charge and recharge according to the manufacturer's instructions and within the specified temperature range; use only the corresponding charger.
• 02A battery that has been subjected to impact, falls, deformation or abnormal heat/smell is taken out of service and kept under observation at a distance from combustible material.
• 03Fire preparedness is different from ordinary fire: a lithium-ion fire can flare up again, and cooling with large amounts of water and isolating the device are often necessary. Follow the DBI/emergency guidance and the company's emergency plan.