- Yuasa Battery, Inc. Automobile Battery Charger User Manual

About Sensors

Many of today’s motorcycles use batteries equipped

with sensors. They’re either built in the battery, or

packed with it.

A sensor is a “low fuel” warning light. It tells you when

you’re getting low – in this case, on electrolyte. The

sensor causes a warning light to flash, signaling that

it’s time to add water to the battery. The cutaway views

below show what a sensor looks like.

Sensors are sort of particular: they don’t go with just

any battery. Which means it’s important to replace the

old battery and sensor with the correct YUASA sensor

battery listed in the applications book. So, sensor rule

one is this: replace both battery and sensor at the

same time.

“But the sensor’s original equipment,” you say. Doesn’t

matter. Being OE doesn’t mean it ‘s OK in another man-

ufacturer’s battery. In fact, OE sensor plugs vary consid-

erably in length, size and diameter. A plug that’s too

long can short out a battery and mess up the electrical

system. If the plug’s short, the warning light will flash

way too early.

Note, too, that even YUASA’s sensor batteries are not

interchangeable; they have different vent locations, sen-

sor wire lengths and diameter of cylinder connectors.

POINTS TO REMEMBER

❐ Replace battery and sensor at same time.

❐ Original equipment sensor isn’t “OK” for a new battery.

❐ Sensor batteries and sensors are not interchangeable – check

Applications Book.

COVER

MAX

MIN

ACID LEVEL

LEAD

CUT-AWAY VIEW OF SENSOR

LENGTH OF SENSOR

SECTION

Selecting and Installing a

New Battery