Home » Forklift Batteries – Hard to Maintain, How to Handle Them
Blog: Forklift Batteries – Hard to Maintain, How to Handle Them
About the Author
Dave Sherman has worked at Abel Womack for more than 30 years. With an extensive service background, he has been a Business Development Account Manager for the past 10 years.
September 18, 2023 –
Electric forklifts have been around since 1951. George Raymond and Christian D. Gibson received the first power-driven narrow aisle material handling truck patent. Batteries have not changed much since then. Cell design still has lead and acid. Plate types and manufacturing specifics have improved. Still lead—still sulfuric acid.
Sure, there are specialty lead acid sealed batteries and Lithium-ion (Li-Ion), but they are not suitable for every application or wallet. We’ll talk more about these later.
I’m guessing here, but 90% of the forklift batteries in use today are lead acid wet cell batteries that require maintenance. The maintenance is hard in that it’s dirty, dangerous, frequent, and never-ending.
An oldie but goody – maybe not
When I started as a service technician, we were taught to find the date code on the battery if we suspected a problem. Anything older than six years was immediately suspect. Even if it had the right voltage overall, and cell voltage did not drop under load, the age alone was an indicator that it might not be performing the way the forklift needed it to. If you had an overheating motor or welding contact tips, the power source had to be considered as a possible problem. That is still the case today. Although the new AC motors and electronics can be more resilient to current/voltage issues, the battery still must perform. In tall and multi-shift facilities, even more so.
Rule of thumb 1: An industrial wet cell battery is good for 1,500 to 1,700 cycles. What is a cycle, you ask? It’s the cycle of charge, cool down, and deplete.
The charge takes the battery to 100%. The cooldown is needed to maximize battery performance and useful life. The depletion is taking the battery from 100% to about 20% by running the truck. (a battery cannot be fully depleted, or it will not recover). Some applications set lift cutouts as high as 30% or 40% as batteries age to protect electric components. As the stored electricity drops, the voltage drops, and the amperage required to do the same amount of work increases, which can cause heat in the electric system, especially motors.
Basically, if you run a forklift for 8 hours a day, charge it for 8 hours, and let it cool down for 8 hours, you’ll get one cycle per day, 5 cycles per week, and 250 cycles per year. You should get 6 to 7 years of life out of it. During the last year of a battery’s performance, it performs at typically 80% of new. That is all still true today.
If you are opportunity charging and running a shift and a quarter to a shift and a half, you are using more cycles per day than a standard shift. You can figure out a 4- to 5-year life. If you are fast charging and running a shift and a half to two shifts, you use more daily cycles than a standard shift. Estimate a 3-year life.
For opportunity charging and fast charging, the battery manufacturers all require a special charger matched to the battery and a data monitor on the battery that communicates with the charger to maintain the warranty. Data monitors that “talk” to the charger can prevent overheating while charging and are great for collecting information to help diagnose problems early.
Rule of thumb 2: Equalize the charge on Friday night and add water on Monday morning.
Equalize charge on Friday because the equalize charge intentionally overcharges the battery for about 4 hours to make sure all cells come up to equal voltage. Every time a battery is charged, fluid is depleted. The water splits to H2 and O2 and vents the accumulated gas. More water must be added. Failure to equalize the charge can leave one or two cells without the required finish charge, resulting in early failure.
Water on Monday, especially during the equalized charge, but it’s true that even after a few minutes of charging, H2 and O2 bubbles are created, and the fluid expands. If you water before charging, you will likely overflow acid out of the battery; not good! The photos are examples of 4-year-old batteries that were frequently “boiled over,” resulting in a loss of acid in the cells and corrosion all over the top of the battery. The corrosion can create short circuits that can create lots of electrical problems with the truck’s circuitry. These batteries, although inside the 5-year warranty, were not warrantable.
The largest forklift users typically have battery rooms for spare batteries, with special venting where batteries are logged in, put on charge, the initial AH recorded, overall AH input recorded, temperatures recorded, and water level then checked after each charge by trained technicians. This blog is not for them. It’s for the warehouse that wants to get warehouse business done and does not want to be in the battery maintenance business.
What can you do?
If you are not swapping batteries every day and do not have a dedicated in-house person to do the required maintenance, you can assign the forklift operator to check/record the initial AH when the charger starts up and the total AH after the charge is complete. He/she is going to get very tired of these extra chores, won’t know when to flag for service, and, unless there is a problem, is just spending a lot of time logging that everything is OK.
You can train the operator to push the equalize button on the charger every Friday, or if you have a smart charger, program it to do so. There is no way for an operator to manually check the temperature while charging or during the cool down. It takes a battery monitor to capture this information.
At the very least, most places install water monitor lights and single-point water strings so the operator can do the battery watering without pulling the battery from the truck. Beware, it’s not an exact science with these systems, and overwatering/underwatering can still be a problem.
Most warehouses do not have operators pull the battery to check that all the single-point injectors are functioning. They are mechanical devices that sometimes fail. Although infrequent, if one cell is not getting water, it doesn’t take long before that cell will need to be replaced. By the way, the water monitor light only checks one cell. Be sure your forklift service provider is pulling the batteries to check the watering system is functioning correctly.
Battery problems typically fall into these categories:
It may be that your operators just can’t stop opportunity charging at lunch and on breaks. They like the extra lift speed when the battery comes off charge “hot.” Not good for the truck or the battery. That’s a life cycle gone and a higher voltage in the electrical circuits.
Perhaps the in-house person you’ve designated to make sure everything is plugged in every Friday for equalized charge and watered every Monday simply was not doing a good job.
It may be that a single-point watering system was overwatering or underwatering, unbeknownst to the in-house person.
Or the charger has a problem. Perhaps the charger isn’t sized right or is not programmed right, or just isn’t working right.
It may be a warranty problem.
Recommendations:
Know your battery company. Either subcontracted through your forklift service company or directly.
Schedule a battery technician twice annually to have the battery pulled to check the single-point water system, the water monitor, the cell voltages, and the cleanliness of the battery. These professionals can also re-train your in-house staff to do daily/weekly/monthly maintenance.
Consider a data monitor that can monitor the charging and discharging of the battery. The data monitor will monitor AH in, AH out, time on a charge, temperature, and cool down time. And which charger was on which battery. The battery company can read the reports typically with a Bluetooth download and make recommendations.
Any indication of sulfur smell or poor forklift performance should be checked out quickly. Make repairs right away. Bad batteries can burn up motors and electronics.
Consider hiring a battery company to do the watering, especially if you have the new lower maintenance type batteries that require watering less frequently.
Know the age and condition of the batteries in your fleet to better budget for replacement. Most battery companies will provide no-cost surveys to identify the fleet and its condition. Lead times for common battery sizes are short, typically 1 – 2 weeks. Lead times for others can be several months out. Nobody likes a forklift that won’t run because it’s waiting for a replacement battery. I’ve seen clients spend thousands of dollars on temporary repairs while new batteries are built.
Have your local dealership run an E-Meter to verify the power requirements for your operation.
You may ask, why isn’t my forklift technician doing all of this?
Some large warehouses do have in-house battery technicians. Most today leave the battery work to the vendor to get the best on-site knowledge for that chemical machine. Leaving the forklift technicians to focus on the electronics and mechanical issues of the forklift itself.
Also, if there are warrantable battery issues, it is best to have the battery tech dealing with it right up front.
They may be a perfect fit for your operation and may not cost that much more than lead acid, especially if you are having trouble getting a battery to last the full 1,700 cycles. The maintenance-free claim for these technologies is true. No watering. No leaking acid, and no chance that a filling system can fail. Data monitors come standard with these batteries.
The Nexsys thin plate pure lead offering is maintenance-free and likes to be opportunity charged. Note that it will have a shorter warranty and potentially a shorter run time than the equivalent-sized lead acid. It does still require an equalized charge. This technology is more susceptible to damage from over discharge than a lead acid battery would be.
The Li-Ion offering is maintenance-free and likes to be opportunity and fast charged. These typically have good warranties and do not require any equalized charge but are also more susceptible to over-discharge than a lead acid battery would be. If treated properly, some high-technology LI batteries will last 10 years or more.
Both of the above technologies are in use and do well in the right environment.
Be aware that not all Li-Ion battery manufacturers have UL ratings, and not all are “allowed” by the forklift manufacturer. Don’t get into a situation where a low-cost Li-Ion battery is causing issues with the forklift. Raymond Corp, for instance, requires extra wiring to ensure that the battery state of charge displays correctly for the operator, and if the Li-Ion battery is going to shut down, the truck is “aware” so that motors can be throttled down. They also endorse LI manufacturers whose technology minimizes the possibility of a thermal event.
Tap into the right technology today
Suppose you want to get on a maintenance program for your lead acid batteries or look at switching to one of the new technologies to get away from battery maintenance. Reach out to your local forklift dealer. We can put power measurement tools into your application to get reports that will help define which technology will work best for your needs.
Curious how a Li-Ion battery might impact your bottom line? Plug your variables into a Li-Ion ROI calculator and see for yourself if a li-ion solution makes sense for your business.
About the Author
Dave Sherman has worked at Abel Womack for more than 30 years. With an extensive service background, he has been a Business Development Account Manager for the past 10 years.
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