A Guide to Bike Batteries

We all know the feeling battery failure can cause. At some point in our lives most of us have gone to start our motorbike only to find that it’s completely dead. This guide to all things motorcycle battery should provide you with some useful hints and tips to help keep your battery in the best possible shape and your bike on the road.
The motorcycle battery is a crucial component of what we call the bike’s triangle of power. The triangle of power consists of the starter motor, alternator and the battery itself. If any of these components are not performing to specification your bike will not start.

Functions of a motorcycle battery

On a typical bike, the battery has five basic power supply functions:
Starting – Supplying power when cranking the engine.
Lighting – Delivering steady power before engine start.
Ignition – Supplying power to the ignition system during engine cranking.
Charging – Operating as a voltage stabiliser to absorb fluctuations in the electrical systems.
System Support – Supporting security systems and ECU memories whilst the ignition is switched off

Issues causing non-start

A motorcycle is generally used as a seasonal vehicle and may remain unused for long periods of time. It is not uncommon for riders to experience issues when trying to start for the first time after an extended period of storage. In most cases the non-start situation is automatically blamed on the battery, however, simple monitoring and maintenance during storage will prevent the majority of these problems.

A lead acid battery is a live product once commissioned and is constantly releasing electrical energy. Even when removed from the bike, the battery is self-discharging at a rate dependent on battery temperature. The warmer the environment, the faster the battery will discharge. Typically, at 10°C the battery loses around 0.1 volts each month rising to approximately 0.4 volts per month at 30° C.

As well as natural self-discharge, the battery may also have to support electrical loads such as security systems immobilisers and ECU memories. To combat this, some riders may choose to remove the battery. Unfortunately this will not stop the natural self-discharge process, which will result in voltage losses and battery damage over time.
With the advent of intelligent chargers, riders can now safely monitor and maintain their battery whilst it is still on the bike. By connecting an intelligent charger for extended storage periods, you will not only ensure that the battery remains at optimum voltage but also allow security systems and ECU memories to remain active. Always check with the manufacturer to ensure your charger has a maintenance made and is safe for unattended charging.

Yuasa Battery development

Yuasa motorcycle technology has been developed and improved over time to fulfil the increasing demands of both bike manufacturers and consumers. Originally, dry charge batteries featured a plug lid for maintenance and an open vent to atmosphere. In 1983 Yuasa introduced dry charge, Valve Regulated Lead Acid (VRLA) sealed maintenance free types. The benefit of these is reduced weight and size, and the elimination of the open vent. From 1999 onwards, the factory activated YTZ wet type, sealed maintenance free, high performance battery was introduced. This removed the need for the commissioning process and allowed angled fitments.

On some bikes it is possible to install an improved specification type, but before doing so you will need to check fitment compatibility. Yuasa’s online battery finder at www.yuasaeurope.com allows you to easily search for your motorcycle and will provide you with all compatible options.

Motorcycle group shot

Battery Commissioning

As most motorcycle batteries are of the dry charge variety, they contain no electrolyte when purchased. This means that prior to instillation they have to be commissioned before they are able to perform in service. It is critical that the commissioning procedure is followed correctly, otherwise the battery’s performance and life will be compromised.

Common mistakes with commissioning include:
– Not following the correct electrolyte filling procedure. Forcing electrolyte into the battery, rather than allowing it to flow naturally, can in extreme cases cause internal damage and premature failure
– Not allowing enough time for the electrolyte to be fully absorbed. The battery must be left to stand for at least two hours once the battery has been filled.
– Not top charging prior to instillation. Due to the manufacturing process, motorcycle batteries will not be in a fully charged state prior to commissioning so will require a top charge before instillation. Check your battery’s instructions for the recommended minimum charge time.

Replacing your bike’s battery

Before fitting your new battery you will of course need to remove the old one, this is a relatively simple process. Start by switching the ignition off and then detach the negative terminal, positive terminal, fixing bracket and exhaust tube (if applicable) in this order. Finish up by giving the area your battery sits in a good clean.

To install your new battery, start by checking that the battery you have bought is the correct specification and size for your bike. You can uses Yuasa’s online battery lookup to do so. Securely fix the battery using the bracket on your bike making sure that it is firm and will not move or vibrate excessively. Attach the terminals, positive first, and re fit the terminal cover. If your battery came with a vinyl exhaust tube securely insert it into the battery’s exhaust elbow making sure that any vented electrolyte will avoid the rider’s leg and other components.


Yuasa Batteries

Over 90% of bike manufacturers choose Yuasa as their original equipment supplier, so the chances are your bike was fitted with a Yuasa battery when it was manufactured. The company’s aftermarket range provides riders with high-quality, reliable batteries manufactured to OE specification.

Yuasa’s world famous high performance YTZ battery range is a favourite amongst powersports enthusiasts. As the only motorcycle battery in the world to incorporate expanded plate technology, the YTZ provides riders with maximum starting power from minimum space and weight. The unit’s completely spill proof design also allows multi-angle fitment.
Yuasa’s Maintenance free VRLA batteries are perfect for people who have better things to do than battery maintenance. Their permanently sealed design means that they never need refilling, they do however still need periodic charging.

Yuasa’s YuMicron range have a high-tech, power-boosting design and are ideal for touring bikes and modified vehicles. For even more cranking power the YuMicron CX range uses lead-calcium technology which substantially reduces self-discharge.