Just like in a vehicle, the battery in a motorcycle provides power so that the motorbike can start. It is also the battery that provides power for the electrical components of the motorcycles to work. Some of the components powered by the battery include the headlights, taillights, etc.
Battery charging in a motorbike applies the same technique as that of a vehicle motor where by the starter or the alternator provides an alternating current. The alternating current then passes through a rectifier before it goes to charge the battery.
Just like in a vehicle it is through this mechanism that the motorbike keeps full charge. This technique eliminates the struggles of having to connect an external charger to have the battery charged.
The Motorbike Charging Mechanism
There is not much difference in the charging mechanism of a vehicle and a motorbike however in motorbikes we have limited space and the alternator is fixed in such a way that it fits within the limited space. In motorbikes, the alternator is inside the engine.
When the start button is pressed, the battery gives power sufficient enough to have the engine started. When the motorbike engine is idling, the engine runs at a low rpm that at times may not be sufficient to power the alternator so that it produces enough current to have the battery charged.
When the motorbike starts moving, the rpm of the engine increases and this in turn makes the alternator produce enough current to charge the battery. Just like in a car, the power that the alternator produces is an alternating current that has to pass through a rectifier to be converted into direct current (DC) which then charges the battery. A rectifier is a series of diodes.
The alternator system for batteries which was made in the 60’s produced direct current which directly charged the batteries. However, the system had a lot of heat produced and it had to be fixed outside the engine to ease cooling.
What Makes up a Motorcycle Alternator?
As mentioned above it is the alternator that provides power so that the battery keeps full charge. This alternator converts the chemical energy into electrical energy and it is rotated by the engine.
The alternator is made up of three components that work together even though they can be changed and serviced individually. The three components include:
The Rotor
The wheel of the alternator that is connected to the crankshaft on one end is what we call a rotor. It is the part that moves and also has magnet sets that revolve and spin through the starter.
The Starter
As the rotor magnets spin through the starter coils, current is induced into the starter coils. Remember that the starter lining has copper coils. The name alternating current kicks in because of the magnet rotation between the north and south poles as the magnet rotates, the current also alternates corresponding to the polarity of the magnet.
The Rectifier
We have mentioned earlier that the current which is produced by the alternator has to pass through a rectifier for conversion before being fed to the motorbike battery. This rectifier through the use of diodes converts alternating current (AC) to direct current (DC).
Can The Motorcycle Alternator Fail?
Like any other electrical gadget, the alternator may fail and when it fails, it means that it will not be in a position to give enough current to keep the motorbike charged fully. Some of the observable signs that the alternator is not working properly include:
- When the motorbike battery does not charge fully even when the bike is in motion. This means the alternator is not working as it should. When the battery keeps getting partially charged, it weakens with time.
- When the alternator has a problem spinning, you will most likely hear a whining sound from the engine. The sound may get more intense when the bike is idling.
- When the motorcycle starts having problems when you accelerate to higher RPMs. The alternator, as we earlier mentioned is connected to the crankshaft, and if it has a rotation problem, the rotation of the engine will also slow down.
What Happens When the Motorcycle Battery Is Deeply Discharged?
Deep discharge means the battery is completely drained and has no power at all. Such cases may arise when you leave the electrical components of the motorbike on when the engine is switched off. In this state, the alternator may not be able to give sufficient power to recharge the deeply discharged battery.
You may be forced to connect the battery with an external charger to have it charged. After charging to full capacity, you can reconnect the battery to the bike for normal charging to resume.
It is worth noting that some VRLA and AGM batteries can be used in motorbikes.
How Do I Store a Motorbike Battery For Long?
When you intend not to use the battery for long, it is advisable to have it in storage when charged to full capacity. Even though you will store the battery when fully charged, it will still undergo self-discharge though at a slower pace compared to when it is in use.
In as much as the battery is not in use, you will need to have it recharged every 6 months so that the battery remains healthy.
We have talked about battery tenders, trickle chargers, and float charging. Another option to explore when the battery is not going to be in use for long is to connect a battery tender or a trickle charger to the battery.
A trickle charger gives a floating current which keeps the battery charge topped up to cater for any loss during self-discharge.
Batteries become weak as they age and the average lifespan of a battery is 3-5 years depending on its usage and maintenance. It reaches a point where a battery can no longer hold charge for long and the only remedy is having a replacement done.
Can a Frozen Motorbike Battery Be Charged?
Just like in a car battery, freezing can occur. You should never try charging a frozen battery.
Batteries do freeze in extremely cold weather conditions especially when they are stored in the cold conditions while not fully charged.
A discharged battery has a higher percentage of water in the electrolyte than sulfuric acid. The water in the battery freezes when subjected to extremely cold conditions.
The frozen water expands and exerts pressure on the plates of the cell. This causes the plates to disconnect, swell, and touch each other. As the water freezes you will notice cracks on the battery casing or an outside swelling of the battery casing.
You should never try charging a frozen battery because a short circuit will occur and the plates will get damaged. In this case, the internal resistance of the battery rises and in turn, raises the temperature as well.
What follows after this is a thermal runaway and the battery will melt and probably catch fire and explode. This is for sure a dangerous scene.
Conclusion
Just like the car batteries, the motorcycle batteries need to be well maintained because they play a very important role in ensuring that the motorbike can move.
The charging system needs to be working properly so that the battery is kept at full charge and the bike does not disappoint you when you need it most.