Yuasa Motorbike battery YT12A-BS / YT12A-WC 12V 10.5Ah (maintenance-free)

The Yuasa YT12A-BS (often referred to as "WC" for "Wet Charged" when supplied already filled) is a compact high-performance motorbike battery in AGM technology. It has been specially developed to provide high starting power in a very small case. It is the standard for many modern Suzuki sports bikes which have little space under the seat but need to start a powerful engine. With a capacity of approx. 10–10.5 Ah and 175 A cold starting current, it is extremely power-dense.

Highlights at a glance

• AGM technology: The acid is bound in the glass fibre mat (Absorbent Glass Mat), which makes the battery leak-proof (up to 45° tilt) and highly resistant to vibration.
• High power density: Delivers the starting power of a classic YTX12-BS, but is much smaller and lighter to save weight on the motorbike.
• Maintenance-free: Thanks to VRLA technology (valve regulated), there is no need to refill with water throughout its lifetime (never open!).
• Special format: Dimensions of 150 x 87 x 105 mm – a special size which is hardly mechanically replaceable by other types.
• Long service life: Sulfation inhibitor ensures longer durability, even if the motorbike stands unused for longer (with proper care).
• WC vs. BS: "WC" usually means factory filled/activated, "BS" is supplied with an acid pack (Bottle Supplied) for initial filling; they are technically identical.

The compact powerhouse for Suzuki GSX-R and SV

This battery is well-known as the original equipment for the Suzuki GSX-R 750/1000, the Suzuki SV 650 (K3 models or newer) or the Suzuki Bandit 1250. The engineers here chose a battery that is extremely flat (only 10.5 cm high) and narrow, to optimise the motorbike's centre of gravity. It should never be confused with the normal YTX12-BS, which is much taller and would not fit.
 

Features

FAQs for Yuasa YT12A-BS / WC

What does the "WC" in my designation mean?

"WC" often stands for "Wet Charged" (charged wet) or an internal production code for batteries that have already been factory filled and sealed and supplied to the vehicle manufacturer. In the retail trade you usually buy the YT12A-BS. After filling and sealing, this is technically 100% identical to your old "WC" battery.

Can I install a YTX12-BS or YT12B-BS instead?

No. This is the most common mistake with this battery.

• YT12A-BS: 150 x 87 x 105 mm (your battery).
• YTX12-BS: 150 x 87 x 130 mm (too tall!).
• YT12B-BS: 150 x 69 x 130 mm (too narrow and too high, Ducati format). You definitely need the YT12A-BS, as other batteries won't fit in the battery compartment or will prevent the seat from closing.

How do I charge this motorbike battery correctly?

Use a smart automatic charger for motorbikes (e.g. Optimate or CTEK XS 0.8) suitable for AGM batteries. Never use a large car charger, as too high a current can damage ("inflate") the small battery. The charging current should not regularly exceed about 1 amp.

Do I need to top up with water?

No, never. After the initial filling (for the BS version), the sealing strip is pressed on and the battery is hermetically sealed. If you open the strip, the battery is destroyed because the chemical balance is disrupted.