What is Potential Energy Recovery?

The public perception of traditional Internal Combustion forklifts—often referred to as diesel or gasoline forklifts depending on their fuel type—is usually associated with heavy noise and environmental issues. In standard forklift operations during mast lowering, oil from the hydraulic cylinder is discharged directly back into the tank, resulting in a waste of potential energy (Note 1). This is where the Potential Energy Recovery technology of electric forklifts becomes crucial for energy savings. Below, CML will introduce how this technology works.

Note 1:  Potential energy is from an object based on its position or state that can be transformed and utilized.

How Potential Energy Recovery Works

Before diving into the energy recovery mechanism, it helps to understand how a forklift's forks raise and lower. This relies on the synchronized operation of the hydraulic system and the motor, which is split into two completely different physical processes:

Lifting Mode (Consuming Electrical Energy)

When the operator initiates a lift, the battery supplies electrical energy to the motor. The motor drives the hydraulic pump to do work, forcefully transferring hydraulic oil into the hydraulic cylinder. The pressure inside the hydraulic cylinder increases, pushing the plunger up to steadily lift the cargo. This process purely consumes electrical energy , but at the same time, potential energy is generated as the fork rises, the higher the more.

Lowering Mode (Releasing Gravity)

When the cargo/fork needs to be lowered, the system does not need to consume battery power to  do so.

Traditional Forklift Approach: The system simply opens a release valve, allowing the hydraulic cylinder to lower while the hydraulic oil flows directly back into the oil tank. The motor and pump remain completely static, wasting the potential energy.

Potential Energy Recovery Approach: The system guides this returning pressured hydraulic oil back through the pump. The backpressure drives the pump to spin backward, which in turn pulls the drive motor into reverse rotation. This turns the motor into a generator (reverse power regeneration) turning gravity back into usable electrical energy!