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Forklift batteries explained – different types of forklift batteries


forklift battery

Information and History of a Forklift Battery

Invented in 1859 by French physician Gaston Planté, lead-acid was the first battery technology put to commercial use. Lead-acid batteries continue to be the leading source of stored energy for forklifts, golf carts, wheelchairs, and automobiles. This is due to their reliability and relatively low cost.

Charging a Forklift Battery

Lead-acid batteries (forklift batteries) are relatively slow to recharge and must be stored in a fully charged state. Charging is required every 30 days to avoid sulfation, which can reduce the battery’s ability to recharge.

Preventing Damage to a Forklift Battery

It’s important to avoid deep-cycling a battery. When a battery is deeply discharged, it strains the battery and shortens its life. You should monitor the battery to ensure it stays above the lower discharge limit. Many forklifts will prevent over-discharge by indicating 0% charge when the battery is actually at 20%.

Life Expectancy of a Lift Truck’s Battery

Forklift lead-acid batteries typically last for 1,500 cycles or more. Maintaining proper charging and watering records can help you claim your manufacturer’s warranty. Battery companies can check how the battery was charged, watered, and discharged through a destructive cell analysis, revealing grid corrosion, depletion of active material, and positive plate growth. Good records can improve your negotiating position for warranty claims.

How Heavy Is a Forklift Battery?

Although lead-acid batteries have a low energy density compared to other battery types, their weight provides an important source of ballast. A typical 3,000 lb capacity reach truck requires at least 1,900 lbs of ballast weight to counterbalance the load. Lead-acid batteries provide both energy and an essential counterweight for safe forklift operation.

Plate Thickness and Ballast Weight

The weight of a forklift battery can also predict its service life. A thicker positive plate contains more active material, meaning it will take longer to corrode and shed as sediment. As a result, the battery’s weight is a good indicator of its lead content and life expectancy. Ask your battery supplier for the weight to compare the value for money. Forklift batteries typically have plates exceeding 1/4” (6mm) in thickness.

Sealed Lead-Acid Forklift Battery

Maintenance-free batteries are popular for use in controlled environments such as pharmaceutical manufacturing or electric pallet trucks. These batteries are sealed, with the acid converted to gel inside the cell. Valved cell caps allow for venting during charging. Over time, the loss of moisture reduces the lifespan of maintenance-free batteries. To extend battery life, manufacturers recommend operating between 40% and 80% discharge. These batteries do not last long if deeply discharged or overcharged.

Temperature of Forklift Battery

The optimal operating temperature for lead-acid batteries is 25°C (77°F). Higher temperatures reduce battery longevity. As a guideline, every 8°C (15°F) increase in temperature cuts the battery’s lifespan in half. For example, a battery that lasts 10 years at 25°C will only last 5 years at 33°C and a little over one year at 42°C (107°F).

Absorbed Glass Mat (AGM) Batteries for Forklifts

AGM batteries are often used in high-performance vehicles due to their durability and ability to withstand shock and vibration. These maintenance-free batteries use absorbed glass mats between the plates to recombine oxygen and hydrogen inside the cells, resulting in almost no water loss. However, they are almost twice as expensive as flooded lead-acid batteries.

Pros and Cons of Lead-Acid Forklift Batteries

Pros

  • Inexpensive and simple to manufacture.
  • Mature, reliable, and well-understood technology. Lead-acid batteries provide dependable service when used correctly.
  • Low self-discharge rate among rechargeable battery systems.
  • Capable of high discharge rates.

Cons

  • Low energy density – poor weight-to-energy ratio limits their use to stationary or wheeled applications.
  • Cannot be stored in a discharged condition – the cell voltage should not drop below 2.10V.
  • Limited number of full discharge cycles – better suited for standby applications with occasional deep discharges.
  • Lead content and electrolyte make lead-acid batteries environmentally unfriendly.
  • There are transportation restrictions due to environmental concerns regarding spillage.
  • Thermal runaway can occur if charged improperly.

For a comprehensive resource on different battery technologies, please visit: https://batteryuniversity.com

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