This article is applicable to forklift traction batteries, which are still the power source for electric forklifts. The internal structure consists of lead plates and electrolyte, requiring water addition for maintenance. Another type of valve-regulated lead-acid battery does not require water addition. This sealed battery is further divided into gel-type and absorbent glass mat (AGM) types. Thin plate pure lead (TPPL) acid batteries belong to the AGM type, which has lower maintenance requirements related to charging.
1. Forklift Traction Batteries Manual
After receiving a new forklift battery, carefully read the product manual and operate the forklift equipment according to the correct procedures. Violating the instructions may lead to unexpected damage.
2. Avoid Overfilling or Underfilling with Water
The electrode plates in the flooded battery are suspended in acid, and as the acid is consumed during use, it needs to be replenished promptly.
If the water level is too low, chemical reactions may occur when the plates come into contact with air, leading to permanent damage. Mild loss may result in reduced capacity, while severe cases can damage the battery, posing risks of overheating and combustion during operation. Low water levels are a significant cause of poor battery performance and damage. After charging, water should be added immediately, or within the last 20 minutes of charging to avoid overflow risks. When adding water, use distilled water and pour it into the mark indicating the maximum liquid level.
Every five charge cycles, observe whether the plates leak out of the acid. If so, add water before charging to ensure the plates are immersed in the acid. For time-saving, an automatic watering system can be used.
3. Check Electrolyte Levels
Checking electrolyte levels is applicable only to flooded batteries, and it is recommended to check approximately every ten charges. As the battery ages, water consumption increases with each use, requiring more frequent checks.
During routine battery maintenance, individual cells need to be inspected. If a significant difference in electrolyte levels between cells is observed, the deficient cells should be replenished.
4. Monitor State of Charge
Whether it’s a lithium-ion battery, sodium-ion battery, or lead-acid battery, it is not advisable to discharge beyond 80% of the rated capacity. Prolonged deep discharging can lead to Forklift Traction Batteries damage and significantly shorten its lifespan.
For both sealed and flooded batteries, immediate recharging is necessary when the state of charge drops to 20% to prevent sulfate formation on the plate surface, causing a reduction in capacity. Fully charge the Forklift Traction Batteries before storage.
5. Observe Temperature
Forklift Traction Batteries performance and lifespan are constrained by extreme temperatures during storage, charging, and usage. Charging is strictly prohibited when the battery temperature is below 10°C or above 45°C. If overheating or a noticeable sulfuric acid smell is detected during use or charging, stop immediately and seek advice. After charging, let the battery cool for several hours before reuse. Store batteries in a cool, dry place to minimize self-discharge.
For flooded and valve-regulated lead-acid batteries, using a dedicated charging curve is recommended for cold environments, such as cold storage. Consult local suppliers for the most suitable batteries and chargers for specific environments.
6. Keep It Clean
Use approved cleaning solutions to handle minor acid spills from flooded batteries. Acid spills can corrode terminals and other structural components, leading to electrical circuit formation and power loss. Moisture can have a similar effect on flooded and sealed batteries. Therefore, batteries, casings, and surroundings should be kept clean and dry.
Regularly check the plugs, connection lines, and output cables of all batteries and chargers for corrosion, wear, and damage. Electrical professionals should conduct inspections at least once a year, including measuring vehicle and battery insulation resistance.
7. Control Charging Time
For traditional lead-acid batteries, charging should not be interrupted once it starts, and each charge should be completed. When disconnecting, turn off the charger power first, and ideally wait for 5 minutes before disconnecting from the charger. Apart from equal charging, overcharging can lead to wastage and battery damage.
Some battery users opt for random charging during breaks between shifts. If fast charging is used, the generated heat can shorten the battery’s lifespan. This practice is not recommended for traditional lead-acid batteries, but thin plate pure lead batteries are an exception. Thin plate pure lead technology allows for fast random charging, as long as the battery is regularly fully charged, and fast random charging does not cause damage or affect the cycle life.
8. Equalizing Charge, Desulfation, and Maintenance Charging
Voltage and capacity differences may occur between individual battery cells. This can be balanced through equalizing charging: a slight overcharge should be performed every five to ten charge cycles, with the charge termination voltage higher than the normal voltage level.
During equalizing charging of flooded batteries, the electrolyte can be „stirred,“ allowing it to return to a more uniform and effective level, eliminating sulfate crystals on the plates. Batteries equipped with electrolyte circulation systems achieve this through gas injection during charging.
Equalizing charging takes a long time, and the cooling time after charging is also extended. Therefore, it is advisable to perform equalizing charging when there is ample time during weekends. Refer to the specific battery’s equalizing charge instructions and be attentive to any overheating during the process. Some chargers (e.g., Hawker high-frequency smart chargers) have automatic equalizing charge functions. Some chargers also have desulfation charging functions, which should be used before normal charging but only when necessary. Some specialized machines use high-frequency electronic pulses to eliminate sulfate crystals, but highly sulfated batteries are irreversible.
Batteries in storage or those experiencing self-discharge during parking need regular maintenance charging to keep them ready for use at any time.
