Forklift Battery Guide: Types, Charging, Maintenance and Lifespan

An electric forklift battery is a traction battery, usually lead-acid or lithium-ion, that powers both the drive motor and the hydraulic pump. It’s also one of the most expensive parts of the truck and, on a counterbalance forklift, part of its counterweight. Choosing it well, charging it correctly and maintaining it extends its life and the truck’s. Browse our electric forklifts for examples of configurations.

What types of batteries do forklifts use?

The vast majority of electric forklifts use a flooded lead-acid battery or a lithium-ion battery. There are also sealed lead-acid batteries, gel or AGM, which are rare on forklifts but common on some smaller machines like pallet jacks and stackers.

Lead-acid vs lithium-ion: the key differences

Criterion	Flooded lead-acid	Lithium-ion
Maintenance	Regular watering, cleaning, equalizing charges	No watering; minimal maintenance
Charging	Full charge recommended, followed by a cool-down period	Usually accepts partial charges during breaks
Gas while charging	Releases hydrogen; ventilation required	No gassing in normal operation
Purchase cost	Lower	Higher
Multiple shifts	Often one spare battery per extra shift	Often a single battery, charged during breaks
Charger	Charger designed for lead-acid	Charger compatible with the battery and its management system

Lead-acid is still the most common choice, especially on the used market, because it’s proven and cheaper to buy. Lithium-ion appeals to businesses running several shifts that want to avoid battery changes. Real differences in cost and lifespan vary by manufacturer: ask the battery supplier for specific figures.

How do you read a forklift battery label?

The battery plate or label shows its voltage, its capacity in amp-hours, its weight and, often, its manufacturing date. Those are the four things to note before replacing a battery or evaluating a used truck.

Voltage (V): it must match the truck exactly. In North America, 24, 36, 48 and 80-volt trucks are common. Each lead-acid cell supplies about 2 volts, so a 36-volt battery has 18 cells.
Capacity (Ah): how much energy it stores. At the same voltage, higher capacity means more run time, as long as the battery fits the compartment.
Weight: on a counterbalance forklift, the battery contributes to stability. The truck’s data plate lists the battery weight to respect.
Manufacturing date: it tells you the battery’s real age, which may differ from the truck’s.

How do you charge a forklift battery correctly?

Charge the battery in a designated, ventilated area, with a compatible charger, following the battery manufacturer’s recommendations. For a lead-acid battery, the general rule is to avoid repeated partial charges and let the battery finish its charge cycle.

Park the truck in the designated spot, forks lowered, brake set and key off.
Check the charger and cables. A damaged cable or melted connector must be repaired before charging.
Connect the charger to the battery in the sequence the manufacturer specifies, then start charging.
Let the charge finish. Interrupting lead-acid charges often shortens battery life.
Let the battery cool down before putting it back in service when the manufacturer recommends it.

Charging a lead-acid battery releases hydrogen, a flammable gas. The charging area must be ventilated, kept free of flames and sparks, and equipped as required, for example with an eyewash station. For the exact rules, refer to the CNESST and your battery manufacturer. The Canadian Centre for Occupational Health and Safety (CCOHS) also publishes a fact sheet on forklift battery safety.

What maintenance does a lead-acid battery need?

A lead-acid battery needs regular watering, cleaning of the top and terminals, and equalizing charges on the manufacturer’s schedule. These simple steps often make the difference between a battery that lasts and one that wears out early.

Electrolyte level: check it regularly and top up with water of the quality the manufacturer recommends, usually after charging, never to the point of overflowing.
Cleanliness: a wet or dirty battery top encourages corrosion and current loss.
Terminals and cables: corroded terminals or damaged cables reduce performance and can heat up.
Equalizing charge: it rebalances the cells. How often is set by the battery or charger manufacturer.
Protection: electrolyte is corrosive. Wear safety glasses, gloves and the required equipment for any work on the battery.

How long does a forklift battery last?

Forklift battery life is measured in charge and discharge cycles, and it varies a lot with the battery type, how hard it’s used and how well it’s maintained. The battery manufacturer states the expected life under normal conditions. In practice, charging habits and depth of discharge matter as much as the technology.

Several signs show a battery is nearing the end of its useful life. The table below links them to the most common causes.

Signs of a worn forklift battery and possible causes

Sign	Possible causes	What to do
Run time no longer lasts a shift	Normal wear, incomplete charges, weak cell	Have the battery tested cell by cell
Power loss when lifting	Discharged or unbalanced battery	Check charging and equalizing
Battery very hot after charging	Wrong charger, faulty cell	Stop and have the battery and charger checked
Corrosion and deposits on top	Electrolyte overflow, poor cleaning	Clean it and review how it’s watered
Swollen or cracked case	Overheating, physical damage	Take it out of service and consult a specialist
Water level drops very fast	Overcharging, battery at end of life	Have the charger settings checked

How do you choose a replacement battery?

A replacement battery must have the same voltage as the truck, fit the compartment, respect the weight on the truck’s data plate and work with your charger. The connector must also match the truck and the charger.

Compartment size: measure length, width and height, plus the connector position.
Weight: a battery that’s too light reduces counterweight and can compromise stability. Never go below the minimum weight listed.
Charger: it must match the battery’s voltage, capacity and technology.
Switching to lithium-ion: check compatibility with the truck manufacturer, the counterweight question and the charger before converting a truck designed for lead-acid.

Used lead-acid batteries are recyclable: give them to a recycler or your supplier instead of storing them indefinitely. On an older truck, also compare the cost of a new battery with the cost of a complete used truck whose battery is in good shape.

What should you check on a used electric forklift’s battery?

Note the battery’s age, inspect its case and terminals, then test run time and power under load during the test drive. A battery at the end of its life can account for a large share of a used truck’s price: it should weigh in your decision.

Age and history: manufacturing date, maintenance, any replaced cells.
Physical condition: no cracks, no swelling, no heavy corrosion, cables and connector in good shape.
Load test: lift a representative load to working height, with no marked loss of power.
Charger: included, compatible with the battery voltage and in working order.

These checks also apply to smaller electric machines like electric pallet jacks and stackers. Our electric pallet stacker guide points out that the battery is often the most expensive part to replace. For the rest of the truck, see our used forklift inspection checklist.

Frequently asked questions about forklift batteries

How many hours does a forklift battery charge last?

It depends on the battery’s capacity, its age, the truck and how hard you work it. A healthy, properly sized battery is generally meant to last a shift. If it no longer does, have it tested before deciding it needs replacing.

Can you charge a forklift battery during lunch?

With a lithium-ion battery, it’s generally possible and even intended. With a conventional lead-acid battery, repeated partial charges are usually discouraged because they shorten its life. Follow your battery manufacturer’s recommendations.

Can you put a lithium battery in a forklift designed for lead-acid?

Sometimes, but it must be approved by the truck or battery manufacturer. You have to account for weight, since the battery acts as counterweight, as well as voltage, connector and charger. A poorly done conversion can reduce the truck’s stability.

What water should you use in a forklift battery?

Use the water quality the manufacturer recommends, usually distilled or deionized water. Top up after charging unless told otherwise, and don’t go over the specified level to avoid electrolyte overflow.

Should you buy a used electric forklift with a new battery?

Not necessarily. A battery in good condition, tested and well maintained, can still give several years of service. What matters is knowing its real condition. At A1 Machinery, every unit is inspected and certified by our mechanics and sold with a parts and labor warranty.

Where do you start?

Write down the voltage, capacity, weight and manufacturing date on the battery, then the length of your shifts. With that information, it’s easy to tell whether your current battery is enough, needs replacing, or whether a different truck makes more sense.

New and used electric forklifts: for warehouses and indoor work
Reach trucks: for narrow aisles and high racking
Electric pallet jacks: for moving pallets at floor level
A1 Machinery’s full forklift inventory

A1 Machinery has over 700 units, each inspected and certified by our mechanics before sale, and lease financing is available. For a question about a forklift battery, or to find a machine that fits your shifts, contact an A1 Machinery advisor or call (450) 467-2224.