Which Battery is Best for Material Handling Walkie / Ride-on Forklifts?

Electric forklifts are powered by 36, 48, 72 and 80-volt battery systems, either lead-acid (Flooded or Gel) or lithium batteries. Lithium batteries must be tolerant of back-fed energy when a motor is stopped. Partial State of Charge (PSOC) operation and high-power output with a stable voltage over the entire discharge period are essential for the performance of the lift and traction system. Usable capacity increases productivity and establishes the operational period between charges. A battery monitoring system can help drive productivity and avoid unnecessary downtime. Additionally, costs for a lead-acid battery room, charging equipment, electricity, spares and maintenance, and safety and carbon footprint will need consideration when selecting a battery system type. Cold warehouse temperatures can negatively impact the lifetime and performance of batteries.

Lead-acid Batteries: packs of either 2-volt batteries are connected in series to attain 36, 48, 72 and 80-volt systems and are used parallel, if necessary, to meet useful capacity requirements. Lead-acid last up to 1400 cycles when discharged to 50% Depth-of-Discharge (Depth of Discharge - DoD) and up to 600 cycles when discharged to 70% Depth of Discharge (DoD). Lead-acid batteries have an average lifetime round-trip efficiency of 65%. Lead-acid batteries should not be disconnected from the battery charger until they have reached full State-of-Charge (SOC). They cannot be opportunity charged. Flooded Lead-acid batteries off-gas when charging and, therefore, must be charged in a separately ventilated room. They must also be topped up with water and therefore spills require containment. Charging generally takes 6-8 hours. All lead-acid-type batteries heat up during charging and require a cool-down period before use. Heat mats can support lead-acid batteries for cold warehouse operations.

Lead-acid battery failure is most commonly caused by acid stratification, extreme temperatures and destructive vibration. Acid stratification naturally occurs in flooded lead-acid batteries and leads to a decline in capacity and charge acceptance. AGM battery technology, or equalization charging (cell balancing) by a charger for flooded lead-acid batteries, will mitigate acid stratification.

Lithium Batteries: 36-volt, 48-volt lithium iron phosphate batteries (LiFePO4) are used in parallel to increase capacity. Lithium batteries last a lifetime of up to 2000 cycles when discharged to 90% Depth of Discharge (DoD). Lithium batteries have an average lifetime round-trip efficiency of 95%. Lithium batteries can be opportunity charged and need not be recharged to 100% State of Charge (SOC). Using a correctly sized lithium battery charger with or without integrated communications, batteries can be charged from 0-100% in as little as one hour without needing a cool-down period. Lithium batteries are safe: no gas, no-spill. They require no water and are maintenance-free. Heat mats can support lithium batteries for cold warehouse operation.