The goal of this article is to help extend the life of your batteries and improve the performance and life span of your lift truck by educating forklift operators on some of the basics of electric forklift battery maintenance for an electric forklift. Making sure your team is aware of the maintenance plan is critical for the longevity of your pallet jacks and lift trucks. A detailed battery maintenance program should be a part of any regular maintenance schedule the same as checking tires or making sure the spark plug is in proper working order. 

FORKLIFT BATTERY CHARGING

Stick to protocol when it comes to forklift battery maintenance and charging your lift trucks. Batteries have a finite number of cycles, if you charge based on convenience instead of sticking to a schedule; you can potentially shorten the battery’s life. The general rule of thumb is to recharge the battery after an eight-hour shift or when it’s discharged more than 30%. If you charge too frequently when it is not more than 30% discharged, you will shorten the battery life. The following charging tips are also considered best practices:

• If possible, let the forklift battery charge completely once you’ve started to charge it. Cutting a charging cycle short can also be harmful for the battery’s longevity. Be sure to fully recharge the battery once every day.
• Don’t let a discharged battery sit for too long - not more than a few hours to one day. By doing so, you increase the likelihood that hard sulfation will develop, which will reduce the run time and life of the battery.
• Don’t over discharge your lift truck battery. If you discharge beyond 80% you’ll be doing long term irreparable damage to the battery and significantly shorten the battery life.
• Be aware of battery temperature when charging. Excessive heat will shorten battery life by half. Keep the forklift battery as close to 25C as is practical. And charging a cold battery around 15C or less requires extra time as well as temperature compensation on the battery charger to achieve proper charge voltages. 

FORKLIFT CHARGING STATIONS

In addition to these electric forklift battery maintenance tips, for safety purposes it’s also highly recommended that a facility be set up with a designated battery charging area. This area should have clear signage, available water supply for eye washing, ventilation, a fire extinguisher and a phone in case of emergencies.  Additionally, these other safety precautions are recommended:

• Prohibit smoking near the designated battery changing area.
• Avoid wearing metallic jewelry while recharging lift truck batteries.
• Use appropriate handling equipment for lifting and moving heavy batteries.
• Wear appropriate protective equipment (safety goggles, gloves, apron, and/or face shield).
• Position forklifts appropriately and apply breaks before charging or changing batteries.
• For batteries with sealed vents, do not recharge with a current greater than 25 amperes.
• If the battery becomes hot or electrolyte fluid begins leaking from the vents, turn off the charger. When the battery has cooled, restart at a lower charging rate.
• Keep accurate records of battery watering, cleaning, inspections, and other maintenance, etc.
• Recycle or follow specified local procedures for battery disposal as they contain hazardous waste.

CHECK AND MAINTAIN BATTERY FLUID LEVELS

Having the right amount of water in your battery is very important for it to function to its full capacity. Have a schedule to check the fluid level of your forklift batteries – approximately every five charging cycles is advised. Check several cells to see if there’s enough water to cover the plastic battery element. If it’s not obvious from inspecting two or three, proceed to check all the cells. If necessary, top off the fluid.

Typically, forklift batteries will need to be topped off every ten charges if they’re brand new, and as mentioned above, should be filled to cover the plastic battery element. Batteries should only be topped off when they are fully charged. It’s also important not to overfill the battery as there needs to be some additional space to account for expansion when the lift truck battery is in use.

Water used in batteries should fall between 5 and 7 on the pH scale and within the batteries recommended levels for impurities. Check the documentation on your forklift battery for specifics on the allowed limits of water impurities. Distilled water is preferred.

Each month you should take a gravity reading of all of the battery’s cells with a hydrometer after a charge. Fully charged, standard forklift batteries typically have an ideal specific gravity of 1.285 (check your battery’s specifications for the exact number for your model).

KEEP YOUR FORKLIFT BATTERY AT A SAFE TEMPERATURE

Oftentimes forklifts are used in rather extreme environments, but for optimal battery life you’ll want to keep the operating temperature at or below 113 degrees Fahrenheit (45 degrees Celsius). If there’s no way around working in hotter temperatures, be certain the lift truck battery has a lot of circulation in the battery compartment so it can cool. Due to chemistry, the life of a battery is reduced by 50% for every 10 Dec C temperature above 25C. So 35C longevity is half of 25C and 45C longevity is half of 35C.

EQUALIZING

Some batteries require equalizing, and if so they will often have an equalizing setting on their charger. What is equalizing a battery? At its core, equalizing a battery means that you are overcharging it to remove sulfate crystals that have built up on the plates. Sulfation, as mentioned in the charging section of this article, can shorten the battery’s life. Equalizing a battery also reverses acid stratification, which occurs when the acid concentration at the bottom of the battery is greater than that at the top. Not every lift truck battery requires equalizing, so check the specifications on your battery before adding this to your forklift battery maintenance routine. For wet cell batteries, these should be equalized about once per week. Do not equalize more than the recommended frequency per operating procedures.  More is not necessarily better!

CLEANING YOUR FORKLIFT BATTERY

Cleaning the top of the forklift batteries with battery cleaner or warm water is not only a good maintenance practice; it is also required on some batteries to maintain the warranty (check your warranty documentation just to be sure). We suggest a monthly cleaning even if it’s not required by your warranty to help avoid build-up, which can cause tray corrosion, faster self-discharge and possibly even impact the forklift’s electronics. Review the safety procedures listed above when preparing to clean a battery.

ADDITIONAL FORKLIFT MAINTENANCE AND FORKLIFT BATTERY RESOURCES

• OSHA’s Forklift page
• Spring Forklift Maintenance Checklist