Battery Care and Maintenance for Material Handling Equipment

by Daniela Fortino September 1, 2023

A critical component of electric material handling equipment is the battery. Batteries must receive proper care and maintenance to ensure optimal equipment performance, longevity, and cost-effectiveness. This article discusses the importance of battery maintenance and best practices to ensure optimal function.

The Importance of Battery Maintenance

Material handling equipment (MHE) is designed to tackle heavy-duty tasks, often in demanding environments. These machines rely on batteries to provide the necessary power to move heavy loads efficiently and safely, ensuring smooth operation of the entire supply chain.

Benefits for proper care and maintenance of batteries in MHE are as follows:

Performance: Well-maintained batteries provide consistent power output, enabling equipment to operate efficiently and meet productivity goals.
Longevity: Regular maintenance can significantly extend the lifespan of batteries, reducing the frequency and cost of replacements.
Safety: Neglected batteries can pose safety hazards, including acid leaks, gas emissions, and even the risk of fire or explosion. Adequate care minimizes these risks.
Cost Savings: Investing time and resources in battery maintenance can lead to substantial cost savings in the long run by avoiding premature battery replacements and reducing downtime.

Best Practices for Battery Care and Maintenance

A common battery type used in material handling trucks is lead acid. These batteries are designed to provide a steady stream of power over an extended period, which is well-suited for the frequent charging and discharging cycles required in warehouses and other industrial environments.

Practicing a comprehensive battery care and maintenance routine is crucial for maximizing the performance and longevity of lead-acid batteries. Below are factors and practices to consider for optimal battery and machine function.

Charging

The charging of lead-acid batteries is heavily influenced by the state of charge and the depth of discharge. The state of charge refers to the charge level in a battery relative to its capacity. For example, a battery with 70 percent of its charge remaining has a state of charge of 70 percent.

The depth of discharge is the opposite of the state of charge. It is defined as the capacity removed or "discharged" from a fully charged battery. Therefore, a battery with a state of charge at 70 percent will have a depth of discharge of 30 percent.

Under normal circumstances, it is recommended to keep lead-acid batteries between 20 to 80 percent of the state of charge and wait until they reach 80 percent of the depth of discharge before recharging. Most new batteries provide around 1500+ charge "cycles." Charging batteries within these ranges helps minimize the number of charge cycles, increasing the battery's lifespan.

Another way to minimize charge cycles is to tailor recharging practices to operations. For example, sporadic or light to medium-duty applications may benefit from opportunity charging. This charging method takes advantage of short breaks to give the battery a partial charge, which can extend its overall life. In contrast, heavy-duty operations may benefit from scheduled charging based on usage patterns.

Overall, charging only when necessary is one of the best ways to extend battery life. It spreads the battery's charge cycles over a longer period and ensures the maximum number of productive years of the equipment.

Equalization charging is also recommended to increase battery lifespan. This process is a deliberate overcharge, designed to minimize the chances of sulfation (build-up of lead sulphate crystals) and stratification (when the electrolyte mixture settles at the bottom) common in lead-acid batteries.

Depending on the brand of charger, equalization can be done by selecting "weekend," "equalize," or "weekly" charge. Doing this approximately every five to ten cycles can help keep the battery performing at peak efficiency.

What to avoid when charging a material handling battery:

Never over-discharge a battery. This can damage the battery, causing the MHE's electrical components to run excessively hot. This can also increase recharge time outside the charger range, leading to only partial battery charges or causing the battery voltage to fall below the threshold required for the charger to activate (leading to a service call to fix the issue).
Avoid interrupting charge cycles. Lead-acid batteries cannot differentiate between partial or complete charging, so interrupting a battery while charging will still count towards the total number of charge cycles available for the machine.
Never allow a battery to sit discharged for more than a few days to avoid "sulfation." If storing a battery is necessary, it is best practice to charge it prior and once every three to six months after that to avoid damage.
Never allow a battery to die completely. It will take over 72 hours of continuous charging to return to full charge. This may also require shop service to restore full charge.

Watering

Lead-acid batteries are immersed in a fluid electrolyte solution of sulfuric acid and water. During charging, the water levels within the battery drop due to evaporation and leaks. "Watering" involves replenishing the electrolyte solution by adding distilled or deionized water. This prevents damage and ensures proper function.

Generally, new batteries must be watered approximately every ten charges for the first few years. Older batteries may require water every five charges. Regular inspections are important to ensure electrolyte levels are not depleted.

It is advised to check two or three pilot cells every five charges to see that the water level is between the minimum and maximum markers (e.g., perforated plastic Element Protector). Add only enough water to fall within the markers.

What to avoid when watering:

Do not over-water. This will cause an overflow on the next charge. The acid loss can reduce battery capacity, generate more heat, increase the evaporation rate, and increase corrosion at terminals. It will cause overflow on the next charge. Acid loss shortens run time, generates more heat, and requires shop service to correct.
Only add water after a full charge (when the battery is cooled).

Cleaning

It is essential to clean a lead-acid battery and its terminals to prevent the build-up of dirt, dust, and corrosive residue. A clean battery operates more efficiently and is less prone to short circuits.

Acid vapors escape during charge, which causes the residue to develop around the vent cap area. The residue is conductive and corrosive. If not rinsed away, the conductivity can cause the battery to discharge itself and generate additional heat during recharge. Over time, the residue will also form clumps of conductive white corrosion that will shorten the battery lifespan and lead to safety concerns if allowed to accumulate.

Rinsing the batteries as needed (or every few months) is advised to remove the acid residue from the battery.

If a battery ever overflows, take a few minutes to rinse it with water immediately afterward (baking soda optional) to prevent corrosion on top of and beneath the battery. Use enough water to thoroughly dilute the spilled acid so it is not harmful to the environment.

Ventilation

Lead-acid batteries produce hydrogen gas while charging, which could cause an explosion if exposed sparks or flame, resulting in injury or death. Ensure the battery charging area is well-ventilated to disperse any hydrogen gas emissions, reducing the risk of explosions.

Temperature Control

Batteries operate best within a specific temperature range. Extreme heat or cold can negatively impact battery performance and lifespan.

It is also essential to stop using a battery if it overheats or emits a strong sulphur smell during use or charging. This signifies a battery, charger, or lift problem that requires a service call.

Training and Documentation

Training equipment operators on proper battery handling, charging procedures, and safety protocols are essential. Keeping detailed records of battery maintenance, charging cycles, and replacements can also help track the battery's health and performance over time.

Identifying Battery Troubles

Recognizing the early signs of battery trouble can help prevent more significant issues. Here are some common warning signs to look out for:

Reduced run time: If the battery's runtime between charges significantly decreases, it might indicate capacity loss or cell damage.
Excessive heat: Batteries should stay cool during charging or operation. Overheating can indicate a problem with the charging process or battery health.
Low voltage: If the battery consistently delivers lower voltage levels, it might indicate cell imbalance or deterioration.
Corrosion: Corrosion around the battery terminals can impede electrical contact and reduce battery efficiency.

When to Replace a Battery

Despite proper care, batteries will eventually reach the end of their lifespan. Knowing when to replace a battery is essential to prevent equipment downtime and maintain productivity. Factors indicating the need for replacement include:

Reduced capacity: When a battery no longer holds a charge for an adequate period, it might be time to replace it.
Excessive voltage drop: If voltage drops drastically during use, the battery's internal resistance might be too high for effective operation.
Irreversible damage: Severe physical damage, such as cracked cases or leaking electrolytes, often warrants immediate replacement.

Lean Inc. Battery Care and Maintenance Recommendations

Proper care and maintenance of MHE batteries are crucial to ensure they perform reliably and effectively. By adhering to best practices, monitoring for warning signs, and knowing when to replace a battery, businesses can maximize productivity, leading to a smoother and more cost-effective workflow.

Below, we have outlined additional steps to charge MHE batteries for reliability, longevity, and performance.

Keep your battery:

Cool - Allow post-charge cooling to below 120 F
Clean - clean, dry batteries last longer and have fewer problems.
Watered - Keep the plates in the cells covered without overflow.
Charged - Unless using specialized chargers, charge at most once every 24 hours.
Discharged - discharge to no more than 80 percent depth of discharge (many forklifts prevent over-discharge with a lift interrupt)
Rotated - It is good practice to rotate your battery fleet if in a multi-shift, multi-battery environment.

Scheduling Maintenance

Batter care and maintenance should be a consistent endeavor. However, certain features or practices are better suited for daily or scheduled maintenance. This is discussed below.

Daily maintenance

Inspect your batteries after a complete recharge and cooling (usually eight hours of charging and eight hours of cooling). Check for frayed cables, broken connectors, etc.
Discharge to no more than 80 percent. You can fool MHE into discharging the battery below 80 percent by performing a boost charge on a break. The machine will think there is more energy in the battery than there is. This may cause damage to the battery and extra wear on the equipment. Remember, the more a battery is discharged, the higher the amps flow into the truck and the greater the wear on the MHE's electrical components.

Regular or semi-regular maintenance

Check that the battery and the charger are correctly matched. Ask your sales rep to perform an audit to be sure. They have been trained to identify mismatched batteries and chargers.
Water the battery weekly upon full recharge. Be sure the battery is filled to at least 1/4" below the vent well neck. The best water is demineralized or distilled.
Equalize charge weekly. Some chargers will automatically do this - but if you need clarification, check with your sales rep.
Twice a year, clean and neutralize your batteries. This will help prolong the life of your batteries.
At the same time, have a battery technician check specific gravity readings, cell temperatures, and voltages.

Need assistance with buying a new material handling equipment battery? Contact us at ted@leanmh.com

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