Why Do Tennis Ball Machines Still Use Lead-Acid Batteries?

Tennis ball machines are becoming faster, smarter, and more portable. App-controlled drills, programmable shot placement, AI vision, and swappable batteries are appearing alongside conventional machines that still rely on 12V sealed lead-acid batteries.

This creates a reasonable question: if lithium batteries are lighter and more advanced, why has the industry not replaced lead-acid batteries already?

The answer is not simply cost or technology. A tennis ball machine must balance purchase price, runtime, motor startup current, charging, transport, and serviceability. Lead-acid remains practical for many established designs, while lithium delivers the greatest value when portability, rapid battery changes, and compact system integration are central to the product.

The tennis ball machine market was valued at approximately $145 million in 2025 and is projected to reach $320 million by 2034. Smart and app-controlled machines are expected to grow faster than the overall category, while portable and lightweight designs are identified as an important product trend. (Reed Intelligence: Tennis Ball Machine Market)

Why Are Lead-Acid Batteries Still Common in Tennis Ball Machines?

Many traditional machines use standardized 12V valve-regulated lead-acid, or VRLA, batteries in 7Ah, 12Ah, or 18Ah configurations. Similar batteries are widely used in UPS systems, emergency lighting, and security equipment, which gives manufacturers access to an established global supply chain.

Lead-acid batteries remain attractive for several reasons:

• Low initial cost

• Standardized dimensions and terminals

• Strong short-duration current capability

• Simple electrical integration

• Easy local replacement

• Relatively convenient transport

• No electronic BMS that can unexpectedly interrupt motor power

Lobster, for example, sells an external battery pack containing an 18Ah sealed lead-acid battery. It is compatible with several Elite and Elite Grand machines and provides an additional 4 to 8 hours of published court time. (Lobster Sports: External Battery Pack)

Spinshot also lists 12V 7Ah and 12Ah replacement batteries for its machines. Its battery guidance says that lead-acid batteries should be recharged after use, stored in a charged state, and periodically charged for 14 to 16 hours to reach full saturation. (Spinshot Sports: Battery Charging Tips)

These are not technologically advanced batteries, but they are familiar, inexpensive, and easy for manufacturers and service centers to support.

Portability Makes Battery Weight More Important

A machine may be described as portable because it has wheels, but rolling it across a court is different from lifting it out of a trunk or carrying it upstairs.

This matters most to players who do not have a private court. The machine may need to be moved from a storage room, loaded into a vehicle, lifted out of the trunk, pulled across a parking area, and carried through a gate. If stairs are involved, wheels offer little help.

Published weights show how widely the category varies:

The Proton demonstrates what a lithium-centered design can achieve: a 17 lb machine, more than 70 mph ball speed, and an 18V quick-swap battery rated for more than 1,000 shots. (Hydrogen Sports: Proton Ball Machine)

Tenniix publishes weights of 18.7 lb for its Basic model and 19 lb for the Pro, with up to four hours of battery life. Its product range also includes a replaceable battery as a separate accessory. (Tenniix Tennis Robots)

At the heavier end, the Acemate S10 weighs 17.8 kg, or approximately 39.2 lb. It can fit in a car trunk when folded and move autonomously once placed on the court, but the user must still lift it into and out of the vehicle. (Acemate S10 Tennis Robot)

Independent YouTube comparisons also treat portability as part of the real ownership experience, not just a specification. The practical question is often whether the machine is easy enough to move every time the player wants to practice. (YouTube: Comparing and Reviewing Seven Tennis Ball Machines)

A lighter battery will not solve every portability problem, but it can remove several pounds from a machine that must be lifted repeatedly.

How Much Power Does a Tennis Ball Machine Battery Need?

A ball machine battery must satisfy two different requirements: energy for the full training session and power for the motors. Choosing a battery only by its Ah rating can overlook the second requirement.

Continuous Energy Demand

During operation, the battery may support two launching wheels, a ball-feeding motor, horizontal and vertical positioning mechanisms, the control board, wireless communication, and a display. Smart machines can add cameras, processors, and additional actuators.

Average power determines whether the machine runs for one, three, or five hours. The required battery energy therefore depends on ball speed, feed interval, oscillation use, computing load, and the amount of idle time between drills.

Short-Duration Power Peaks

Launching motors can draw more current during startup and while recovering speed after a ball passes through the wheels. Rapid feeds, heavy spin, simultaneous motor acceleration, or a temporary jam can increase the short-duration load.

Lead-acid batteries tolerate this behavior well. A representative GS Yuasa NP18-12 battery is rated at 12V and 17.6Ah, weighs approximately 6 kg, and supports a much higher five-second discharge current than its normal training load would require. This helps explain why traditional machine designs can use relatively simple lead-acid power systems without nuisance electronic shutdowns. (GS Yuasa NP18-12 Specification Sheet)

A lithium replacement needs more than sufficient energy. Its cells, BMS, wiring, fuse, and connectors must all handle the measured motor-current waveform without excessive voltage drop or an unnecessary overcurrent trip.

What Problems Do Lead-Acid Batteries Create?

The main disadvantage is weight. A typical 12V 18Ah lead-acid battery weighs approximately 6 kg, which can represent a large portion of the total weight of a portable ball machine.

Lead-acid capacity is also influenced by discharge rate. The rated Ah value is commonly measured over a long discharge period, while the usable capacity can be lower when the battery is discharged faster. Voltage also declines gradually as the battery empties, which may affect motor performance if the machine does not compensate for the change.

Maintenance is another concern. Leaving a lead-acid battery discharged can shorten its service life, so an occasional user must remember to recharge it after practice and during long storage periods.

Lithium can reduce these problems, but only if the replacement battery is correctly designed for the application.

Lead-Acid vs. LiFePO4 for Tennis Ball Machines

LiFePO4 is attractive for traditional ball machines because a 12.8V battery can be developed around a system originally designed for a 12V lead-acid supply. It can also provide lower weight, stable discharge voltage, faster charging, and integrated monitoring.

The weight difference can be substantial. A 12.8V 18Ah LiFePO4 reference battery with nearly the same enclosure dimensions as a traditional 18Ah lead-acid battery weighs approximately 2.49 kg, compared with about 6 kg for the lead-acid example. However, its BMS is rated for 18A continuous and 80A for three seconds, showing why output limits must be checked rather than assuming that every LiFePO4 battery is suitable for a launching motor. (Canbat 12.8V 18Ah LiFePO4 Specification Sheet)

For a traditional 40 to 50 lb machine, reducing battery weight by approximately 3.5 kg could lower total machine weight by around 15%. That is meaningful when lifting the machine, although it may not justify a large price premium for every buyer.

Can a LiFePO4 Battery Directly Replace a 12V Lead-Acid Battery?

Not automatically. Similar voltage and enclosure dimensions do not guarantee system compatibility.

Before replacing a battery, verify:

• Nominal and fully charged voltage

• Maximum motor startup and stall current

• BMS continuous and peak-current limits

• Overcurrent protection delay

• Battery compartment dimensions

• Connector type, polarity, and cable size

• Fuse rating

• Charger voltage and charging profile

• Original battery gauge behavior

• Operating and charging temperature

• Required runtime at low state of charge

The charger deserves particular attention. A lead-acid charger may use float charging, maintenance charging, or a control method that was not designed for a lithium BMS. Even when the maximum voltages appear close, the original charger should not be treated as compatible without verification.

Lithium batteries also introduce different transportation responsibilities. Lithium-ion batteries must pass UN 38.3 testing, and stand-alone lithium-ion batteries shipped by air are classified as UN 3480. IATA's 2026 guidance also requires stand-alone batteries to be shipped at no more than 30% state of charge, while batteries above 100Wh are subject to stricter packing provisions. (IATA 2026 Battery Guidance Document)

Which Machines Benefit Most From Lithium?

Lithium does not provide the same return in every product category. The value depends on machine size, purchase price, usage frequency, transport requirements, and the original battery configuration.

Entry-Level Machines

Entry-level machines using 7Ah batteries are highly price-sensitive. Their battery capacity and replacement cost are low, so a lithium upgrade may add more cost than value.

Traditional High-Speed Machines

Traditional high-speed machines using 12V 18Ah batteries present a better opportunity. Manufacturers can keep a lower-cost lead-acid model while offering a lighter lithium configuration for players who regularly transport their equipment. Lobster already separates the battery from the machine in some configurations to make lifting and indoor charging easier. (Lobster Elite One)

Compact Smart Ball Machines

Compact smart machines have the strongest case for lithium. Their buyers already value portability, app control, rapid setup, and swappable power. In this segment, the battery helps define the product rather than simply replacing a hidden component.

Commercial and Club Machines

Commercial clubs have a different priority. They may accept a larger battery if it supports several training sessions, faster turnaround, more charge cycles, and easier battery-health monitoring. Spinfire, for example, offers an 18Ah LiFePO4 option with a published runtime of 3 to 8 hours. (Spinfire Pro 1 Ball Machine)

Grepow Battery Options for Ball Launchers

Compact tennis and pickleball machines generally need a smaller, lighter battery than Grepow's current standard high-discharge lead-acid replacement models. For these products, a customized 12.8V, 18V, or 25.6V battery can be developed around the actual runtime target, motor-current waveform, enclosure, connector, and charging system.

For larger commercial ball launchers, mobile training robots, or multi-motor sports equipment, Grepow currently offers two higher-capacity reference platforms:

• The Grepow LFP12-45 provides 12.8V, 45Ah, and 576Wh, with 500A continuous discharge and up to 1,800A peak output.

• The Grepow LFP24-22 provides 25.6V, 22Ah, and 563.2Wh, with 400A continuous discharge and up to 1,700A peak output.

These two models are not universal replacements for compact tennis ball machines. Their capacity, dimensions, and weight are better suited to larger systems with higher energy demand or multiple motors. Every application still requires voltage, current, charger, mounting, and connector verification.

Explore the complete Grepow high-discharge LiFePO4 lead-acid replacement battery series.

Conclusion

Lead-acid batteries remain common in tennis ball machines because they are inexpensive, standardized, easy to replace, and capable of supporting motor startup loads. They remain a practical choice for established machines where cost matters more than weight.

Lithium becomes more valuable when the machine must be lifted into a trunk, carried upstairs, moved between public courts, or designed around a compact enclosure. The best opportunity is not a universal battery swap. It is a properly engineered lithium system that reduces weight while maintaining runtime, motor recovery, charging compatibility, and low-SOC performance.