Lead-acid or lithium-ion battery for warehouse equipment: what to choose

Lead-acid batteries are a better choice for single-shift operations with long overnight charging windows, while lithium-ion batteries are a better choice for two- and three-shift operations where charging time and availability are critical. When choosing, you need to compare battery price, operating hours, charging infrastructure, maintenance, and the need for backup batteries. The difference between the technologies is best seen when comparing downtime hours and life in thousands of cycles.

Charging time: the difference determines the number of changes

A typical circuit of a classic lead-acid battery is “8–8–8”:

• 8 hours of work;

• 8 hours of charging;

• 8 hours of cooling.

For one shift, this is the normal mode: after work is completed, there are 16 hours until the next start.

The lithium-ion battery shortens the cycle. For example, in Jungheinrich equipment, the batteries are fully charged in 60 minutes, and to 50% in about 20 minutes. The declared operating range is 8–16 hours. For a lead-acid battery, the same manufacturer gives 360–720 minutes of charging and 6–12 hours of operation.

That is why in three-shift mode, lithium supports intermediate charging, while lead chemistry requires battery replacement.

What changes in costs during operation

A lead-acid battery has a lower initial cost but requires regular water topping up and cleaning. Multi-shift operation adds backup batteries and a place to charge them. Typical life is 1000-1500 cycles. Toyota’s lithium-ion forklift batteries can withstand up to 9000 charge cycles. They use 16% less energy to recharge.

Therefore, lead batteries are better suited for smaller scale operations, temporary projects, and the gradual development of a logistics system, while lithium batteries are better suited for savings in large warehouse complexes.

Which scenario is optimal for the warehouse?

The choice depends on the actual daily load with which the warehouse equipment operates :

• 1 shift of 8 hours: lead-acid battery if a lower initial budget and overnight charging are priorities;

• 12–16 hours of operation: lithium-ion battery with recharging during technological breaks;

• 3 shifts or 24/7: lithium-ion system with charging points near regular downtime areas;

• small fleet with low load: lead technology leaves more budget for the fleet itself.

To put the scale into perspective: in the classic 8–8–8 scheme, one machine operating 24/7 uses three lead-acid batteries in rotation. For a fleet of 10 such machines, that’s 30 sets. The lithium-ion scheme keeps the battery in the machine and recharges it during short breaks.

What constraints should be placed on the solution?

For a lead system, the main limitation is time: 8–12 hours of charging plus approximately 8 hours of cooling after every 8 hours of use. Lithium, on the other hand, carries the start-up costs: the initial price is higher, and charging points need to be located where the equipment is actually idle. Intermediate charging is possible even during breaks of 5–10 minutes.

Switching to lithium may also require different charging equipment and redesign of charging areas. Therefore, the final cost calculation should consist of five items: batteries, chargers, backup kits, maintenance and downtime. Comparing this amount over the same period of operation shows the economically stronger scenario.

When planning the purchase of equipment and batteries, you should also consider your warehouse scaling plans. If the volume of activity increases significantly or only sporadically in the future, it is worth planning to at least partially convert the machines to lithium batteries.