How To Choose The Right Forklift Battery

After determining which size forklift battery for sale is compatible with your vehicle(s), the next – and most important – consideration to take is which type of electric forklift battery technology to use: lithium vs lead acid forklift batteries. 

Commercial forklifts are generally powered by either of these two main types of batteries:

• lead-acid
• lithium-ion 

The technology behind each of these industrial batteries differs greatly, and, therefore, has a different impact on forklift efficiency. 

Lead-acid batteries are the old-school standard for powering forklifts. It is a bulky, liquid-filled unit with a removable top that generates electricity via a chemical reaction of lead plates and sulfuric acid. It’s technology that goes back to 1859, and involves regularly refilling of the units with water (which is also necessary for the electricity-generating chemical processes happening within).

Lithium-ion batteries are a newer technology, having been first used in a commercial product in the early 1990s, a Sony camcorder.  Lithium-ion batteries have many different chemistries.  One of the most popular chemistries for the material handling industry is Lithium Iron Phosphate(LFP).  It is more compact and energy dense than lead-acid.  The cells are sealed shut and require no water maintenance.  

Length of a Forklift Battery’s Service Life

Like any business expense, electric forklift batteries are a cost that needs to be dealt with regularly.

Which type of battery a company uses in its forklifts determines how often workers will have to replace the battery. Lead-acid and lithium-ion batteries have different lifespans:

• Lead-acid: 1000 and 1500 cycles
• Lithium-ion: Between 2,000 and 3,000 cycles

These are averages and may vary based on how well the batteries are maintained.

Lithium-ion batteries need to be replaced less frequently, which is a major driver for business owners to prefer them to conventional lead-acid batteries – which need to be swapped out for new ones more often.

Maintaining Forklift Battery Capacity

Both lithium-ion batteries and their lead-acid counterparts should be cared for properly if they are to perform up to their full potential. Their service life will diminish if proper electric forklift battery maintenance isn’t carried out as it should be. 

In order to maximize service life and overall battery capacity, certain measures should be taken for users of both battery types. However, lead-acid batteries require more care and attention compared to lithium-ion.

Lead-acid forklift batteries require:

• Equalizing (Cell Balancing): Traditional technology like this leads to a frequent state where the acid and water inside become stratified (separated horizontally with the acid more concentrated closer to the bottom). This state forms sulfate crystals towards the bottom of the cells and weaken their ability to hold a charge.  Equalizing will break up the sulfate crystals but if the battery has been neglected for too long the crystals will not break. 
• Temperature Control: Lead-acid batteries must be kept within a certain temperature range, or else they will have a shorter working life. On top of that, they also get very hot while charging, which requires them to be charged and stored in a temperature-controlled space.
• Fluid Level Management: These types of units must be checked to ensure they have enough water about once every 10 or so charging cycles.

Run Times For Lithium-ion vs Lead-Acid Forklift Batteries

Lithium-ion batteries are much less needy when it comes to electric forklift battery maintenance, as they equalize automatically, function well in much higher temperatures (making temperature mostly a non-issue), and don’t require any fluid level management.

For comparison:

 What one of our clients says.

Andrew Wayts - SpartanNash Equipment Maintenance

When it comes to electric lift vehicles, forklift battery specifications aren’t the same across the board. Forklift battery weight, size and voltage vary substantially, depending on which type of vehicle they are powering.

Generally speaking, forklift battery sizes are chosen based on how large the vehicle is, with different types of electric lift vehicles typically getting one of these four voltage options:

• 24-volt forklift battery
• 36-volt forklift battery
• 48-volt forklift battery
• 80-volt forklift battery

A 24-volt forklift battery would be appropriate for some of the smallest types of electric lift vehicles, such as:

• end riders
• center riders
• walkie stackers
• electric walkie pallet jacks

Meanwhile, 36-volt forklift batteries are designed for mid-sized electric vehicles, like:

• narrow aisle forklifts

The 48-volt forklift batteries are designed for large electric vehicles, like:

• counterbalanced electric forklifts
  
  

How an electric lift vehicle’s battery is recharged for continued commercial use has a major effect on how efficiently a business can operate, especially if there are any battery charging station requirements.

As you can imagine, lithium-ion batteries are the newer of the two types of battery technology, so their charging is faster and less complicated. Let’s take a look at how charging is different between these two forklift battery types:

“Opportunity charge” refers to the ability to charge on an as-needed basis, while the forklift has a little downtime (or whenever there’s an opportune moment).

• Lithium-ion batteries can be opportunity charged and don’t need to be recharged to 100% forklift battery capacity.
• Lead-acid batteries mustn’t be disconnected from their forklift battery charger until they have reached full forklift battery capacity, and cannot be opportunity charged.

Moreover, if either of these types of batteries isn’t charged correctly, they will deteriorate in quality as time goes by – with lead-acid units having much stricter guidelines when it comes to a healthy charging technique.

Forklift Battery Charging Station Requirements

The physical location of your forklift battery charger system is a much bigger consideration than many business owners realize.

Lead-acid units have specific forklift battery charging station requirements that lithium-ion units do not. After all, lithium-ion industrial batteries are plugged straight into a wall, and they don’t need to be removed from the vehicle to start recharging. There aren’t really any further actions that need to be taken in order to do a simple recharge.

With lead-acid forklift batteries, however, the units must be removed from the vehicle completely and placed onto a separate forklift battery charger – many of which have the ability to perform equalization. If there are many forklifts in operation, then there will need to be multiple chargers as well as a space for multiple units to cool down after fully recharging. This will involve employees having to regularly lift and support a full forklift battery weight on a regular basis.

Businesses that use lead-acid batteries need space to both charge and cool off multiple batteries simultaneously if they want their company to run smoothly, which often requires one or more separate rooms dedicated to just that. On top of that, lead-acid forklift batteries get very hot while charging, which necessitates a temperature-controlled space to maintain forklift battery charging station safety.

Lithium-ion forklift batteries don’t need a separate space, don’t need to cool down, and don’t require a fully-charged spare at the ready when another one fully discharges – it can be recharged on the spot.

It’s not just the charging that requires close attention and regular checks – the fluid inside of lead-acid industrial batteries involve regular work.

Lithium-ion batteries are sealed shut, and the electricity-generating chemicals inside will stay inside, requiring no liquid-related effort by forklift operators.

Lead-acid batteries are quite the opposite, on the other hand, and require an entire forklift battery watering system that employees must learn to abide by if they want the battery to function well for its maximum possible service life.

The lead-acid forklift battery watering system involves:

• Only topping off with water when it’s fully charged and cooled down
• Refilling water often enough so that the top of the lead plates is never exposed, which is approximately every 10 charge cycles
• Being careful not to overfill with water
• Leaving enough space for the liquids inside to expand, which happens when the battery is in use
• Use water between 5 and 7 on the pH scale

There are battery water monitoring systems that can automatically let you know when water needs to be added, or it can be done by checking it yourself.

There are also battery watering systems that automatically add exactly the right amount of water, which can also be done manually.

With such powerful chemicals involved, safety is of the utmost importance when handling both of these forklift battery types – though one of them clearly offers a clear safety advantage for a typical workplace. Let’s examine lithium-ion vs lead-acid forklift batteries as it relates to safety in the workplace.

Lead-acid forklift battery safety risks:

• Spills: The highly-toxic sulfuric acid within these batteries can absolutely spill out, especially since this type of unit needs to be watered about once a week. If watering isn’t done safely, your employees will be at risk – which necessitates a chemical washing station in the workplace.
• Overheating: These batteries get incredibly hot while they charge, and can leak an explosive gas after reaching peak charge, making temperature control very important to safety. Forklift battery charging station safety must be carefully managed.
• Dangerous Gases: If lead-acid batteries are over-charged, specific hazardous gases can be released into the air. Add a room that is not well ventilated and you have an extremely hazardous situation on your hands. The three main gases that can be released are hydrogen sulfide, hydrogen, and sulfur dioxide. If you smell a rotten egg smell, hydrogen sulfide is the likely cause and you should take immediate precautions. A standard catalytic LEL gas sensor should be installed in the charging room above the level of the gas. Or, you can measure the hydrogen by means of a substance-specific electrochemical sensor. Since hydrogen is lighter than air, the sensor needs to be installed in the appropriate location.
• Old or Corroded Batteries: Brand new lead-acid batteries that are charged appropriately will not expose workers to the aforementioned conditions. However, old or corroded lead-acid batteries are a real danger to the people working with them and should be properly disposed of immediately.

Lithium-ion forklift batteries are sealed, so there is no potential for acid spills, corrosion, sulfation or any sort of contamination in the workplace. The chemical combination within these more-advanced batteries does pose a minuscule risk of expelling a corrosive gas when it comes in contact with water, but it’s quite rare.

On the surface, a lead-acid battery may seem like the better investment than a lithium-ion forklift battery. That would be true if you only looked at the initial cost of buying a battery.

However, when prudent managers and supervisors take a deeper look at the total cost of ownership between lead-acid and lithium-ion batteries, they see a far different picture.

Let's take a look at purchasing one (1) battery for a forklift and delve a little deeper into the actual numbers to see what the real cost of ownership is.

(These numbers are used as an estimate and should not be deemed as accurate. They are only for demonstration purposes. Every effort has been made to provide an accurate picture as possible.)

The following cost of ownership calculation is based on a 5-year period

If you only look at the initial forklift battery price purchase, you would see slight savings when purchasing a lead-acid forklift battery. When Operating and Energy Costs are factored in the total, overall savings are quite significant for the lithium-ion forklift battery. 

A total savings of $22,527 can be realized, per battery, over a 5-year period. If your fleet consists of 10 forklifts, that's a savings of $225,270 over 5 years.

More Energy Efficient With No-Water Maintenance and Increased Safety

For many managers and supervisors who are concerned with productivity, the no-water maintenance factor of lithium-ion batteries makes a switch from lead-acid an easy decision. 

When you add lithium-ion stable cell battery chemistry and an overall 40% total efficiency improvement, 30% for walkies and 50% for class 1 forklifts, the future of the material handling and ground support equipment industries is on a path to reduced costs and environmentally-friendly technologies.