Important because it is a consumable product. BS Battery that brings out the potential of your car

PR] Marunaka Yoko Text: Akira Kurita[/fontsize

Motorcycle batteries are more than just a power source for cell motors. In modern fuel-injected (FI) vehicles, they also supply power to the fuel pump, ECU, and various sensors, and it is no exaggeration to say that they are "another fuel" along with gasoline. While many battery manufacturers are competing with each other, BS Battery, a fast-growing brand from France, is attracting more and more attention for its high technology and wide range of more than 400 variations, which are trusted by many motorcycle manufacturers.

Battery performance determines the performance of a motorcycle.

The engine starts when the ignition key is turned on and the starter button is pressed. In such a commonplace routine, the most important thing is not gasoline or engine oil, but the battery. In the days when motorcycle engines were kick-starter and carbureted, even if the battery performance was low, the bike could still run as long as the engine started. Some motorcycles were even battery-less, meaning that they did not have a battery. Fuel-injected (FI) cars, however, continuously consume electricity to run the engine, including the fuel pump and ECU. Of course, when starting the engine, the cell motor must be turned, which draws a large current. Some smart motorcycles even warn the driver of low voltage, making the battery the heart of the vehicle's reliability. Battery life varies greatly depending on the environment in which they are used, but they cannot be repeatedly charged and discharged forever, and a typical lead-acid battery lasts about 2 to 5 years. The life expectancy of a lead-acid battery is generally 2 to 5 years. It may be even shorter for vehicles that are driven short distances or stored for long periods of time during the winter. In other words, no matter how high-performance the battery is, it will have to be replaced at some point. Sulfation, the most common cause of battery deterioration, is a decrease in the effective capacity of the electrodes, which reduces the ability to charge and discharge, and prevents high current flow even if the apparent voltage is increased. The performance of the fuel pump and ignition coil is then reduced, and the overall performance of the bike suffers. Therefore, it is ideal to "consider replacing the battery when you begin to feel a decline in performance," rather than to "think it is still OK because the cell is still turning.

BS batteries are used as genuine products by motorcycle manufacturers for their high reliability.

Founded in France in 2008, BS Battery has developed products ranging from open 6V lead-acid batteries to lithium batteries, and its lineup boasts a breadth of over 400 types. Although BS Battery is an emerging brand among battery manufacturers with a long history, it is currently used by numerous European manufacturers, including Aprilia, MV, Piaggio, and Royal Enfield, as well as being recognized by vehicle manufacturers, including Japanese manufacturers, as an accessory. It is also recognized as an accessory by vehicle manufacturers, including Japanese manufacturers, and is sold in more than 80 countries including Japan. The following factors are behind the growing market share of BS Battery, for which Marunaka Yoko, which develops "standard parts" that are useful for maintenance and repair, is the authorized distributor in Japan.

A wide range of products for different applications.

The strength of BS Battery lies in its extensive product lineup. Rather than specializing in high-performance products, the company offers a wide range of products, from the open type batteries used in old and out-of-print vehicles to MF batteries, AGM batteries, SLA batteries, and even lithium-ion batteries, allowing customers to select the optimal product for their vehicle model, application, and budget.

[Expanding presence through OEM and OES adoption

BS Battery is not an aftermarket-specific brand, but has a proven track record as an OEM, meaning genuine manufacturer adoption, and as an OES, meaning genuine accessory and aftermarket parts supplier, and as mentioned earlier, has business relationships with numerous vehicle manufacturers. Meeting the requirements of motorcycle makers has led to a virtuous cycle of technological refinement and further performance improvement. In recent years, the company has also been actively involved in MotoGP and world championship-level racing.

High cost performance

The main attraction of these bikes is that they offer the same level of performance as Japanese manufacturers, but are sold at a reasonable price.

BS Battery has a wide lineup of products from lead to lithium.

Next, let us introduce the types of batteries manufactured by BS Battery and their features.

Open type]

The open type was the mainstay of lead-acid batteries before the advent of MF batteries. Although there are no examples of open type batteries being used in new motorcycles available today, there are still many old and out-of-print vehicles that use open type batteries. Since the water in the electrolyte in an open type battery volatilizes as it is charged and discharged, it is essential to periodically check the amount of liquid and rehydrate the battery. The open type BS batteries also feature electrode plates that are less susceptible to sulfation, which reduces performance degradation during long-term storage.

MF and SLA

In contrast to open batteries that require periodic rehydration and maintenance, the mainstay of today's batteries is the MF (maintenance-free) battery, which has no electrolyte volatilization. Both types are sold with the electrolyte poured and recharged at the factory. Both types use AGM (absorbent glass mat) electrodes to prevent electrolyte leakage. SLA also offers SLA MAX for Harley-Davidson, which features a high-capacity design for both improved starting performance and long life.

LITHIUM and LITHIUM MAX

Lithium batteries are increasingly being used not only in the aftermarket but also in new vehicles, and BS Battery is currently focusing its efforts in this area. BS Battery also offers the LITHIUM MAX, which dramatically improves starting performance by doubling the capacity compared to previous models.

The appeal of lithium batteries is not limited to customization and tuning, but also includes high practicality

While open-circuit, MF, and SLA lead-acid batteries are in high demand, lithium batteries employing LiFePO4 (lithium iron phosphate) are by far superior in every respect, especially performance. Its features and advantages are as follows.

[Overwhelming weight reduction effect

The battery is one of the heaviest parts installed in a motorcycle, and its overwhelming lightness, about one-third that of a lead-acid battery of the same class, makes it an effective weapon in motorsports. BS lithium batteries are also used in the baby-faced racers entering the 2026 Suzuka 8 Hours Endurance Road Race, one of Japan's most popular motor sports events.

[Extremely high starting performance

The battery's internal resistance is extremely low, so it can discharge a large current at once even to equipment that consumes large amounts of power, such as cell motors, and can be recharged quickly because it generates little heat. In addition, the battery is more resistant to repeated recharging than lead-acid batteries, and its ability to maintain cranking performance at low temperatures has greatly improved its performance during wintertime use.

Low self-discharge]

Users who do not ride for long periods of time will also benefit. Even after long-term storage at a level that requires constant recharging (maintenance recharging) for lead-acid batteries, BS Battery's lithium batteries maintain high voltage even after 12 months of storage at room temperature.

[Longer service life

Lithium batteries have various advantages as replacements for lead-acid batteries. Although lead-acid batteries have the advantage when comparing product price alone, the life of a lithium battery is generally said to be three times longer than that of a lead-acid battery, and long-term use of a lithium battery should be enough to absorb the difference in price.

Unique LITHIUM MAX

As mentioned above, BS Battery's lithium batteries come in two types: LITHIUM and LITHIUM MAX. The basic LITHIUM model, BSLi-02, BSLi-03, and BSLi-04/06, is highly versatile and can cover 80% of the vehicles currently on the market. LITHIUM MAX, on the other hand, was developed for a different purpose than conventional lithium batteries. As explained earlier, the replacement of lead-acid batteries with lithium batteries results in a lightweight and compact battery, but the main focus of LITHIUM MAX is to increase capacity, which is directly related to battery performance. To achieve this, a large pouch cell was adopted. A pouch cell is like the electrode plates and electrolyte in a lead-acid battery, and the larger the pouch cell, the greater the charge and discharge capacity. Lithium batteries have a much higher energy density than lead-acid batteries, so they can be made more compact, but the LITHIUM MAX prioritizes increasing the power supply capacity to the cell motor and increasing the absolute capacity. As a result, the main body size is larger than that of LITHIUM, but it still has the advantage of being lighter and more compact than lead-acid batteries.

Choose a BS battery that you can use with peace of mind.

Like tires and brake pads, batteries are consumable parts that should be considered as regular replacement parts. If the cell motor is running sluggishly, the voltage drops frequently, or the voltage drops within a few days after connecting the battery charger, it is a sign that it is time to replace the battery. For batteries, maintaining a state of "safe use" rather than "still usable" will help avoid problems. Marunaka Yoko's BS battery page includes data on all products from lead-acid batteries to lithium batteries, as well as a compatibility chart of open type → MF → SLA → lithium that can also be used for upgrade purposes. If you are planning to go on a long touring trip during your summer vacation, replace your batteries with BS batteries before you go and get peace of mind.

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