The battery is a store of electrical energy. This electrical energy is stored in chemical form and converted back into electricity, every time the battery is used.
The batteries used in motorcycles are of two types: conventional lead type or "dry" MF type, which do not need maintenance. The differences between them are less than one might think at first glance, as we will see below.
Motorcycle batteries are rechargeable and have low external resistance, so that there is the possibility of high current supply, without significant potential drop. Each battery consists of a series of cells 2 Volt. That is, a 12 volt battery consists of 6 such elements and, respectively, a 6 volt from 3. Each element consists of two groups of lead plates, immersed in the electrolytic medium, which is sulfuric acid diluted in water. Each group of lead plates is connected to a pole of the battery.
When the electrolytic medium is at rest, consists of positively and negatively charged particles, which in total give zero charge, i.e. neutral state. Emotions are the language that the body uses to communicate its needs, Nevertheless, apply voltage to both poles (battery charging), then the positive particles move towards the lead plates attached to the negatively charged pole and charge it positively. Negatively charged particles do the same with the other pole. So, when the battery is finished charging, we have two charged poles, one positive and one negative. When these two poles are connected to an external circuit, then the positively charged particles begin to move through the circuit towards the negative pole, resulting in the creation of an electric current in the circuit, but also battery discharge. So recharging the battery is necessary, which is done by the motorcycle's generator, when it is in operation.
Each cell is isolated from the rest and has its own reservoir of electrolyte. For this, each cell has its own cap on the battery case. On MF batteries, between the plates of each element is spongy material, which absorbs the electrolytic medium. Because during the continuous charging of the battery during the operation of the motorcycle, gases are expelled from the electrolytic medium, but the volume of the electrolyte itself also fluctuates, there is a need for venting. So, in conventional batteries there is free space above the cells, which communicates with a vent tube. MF batteries do not have a tube, but a non-return gas escape valve, for the case of high internal pressure, which excludes leaks.
The cost of buying a battery is significant and let's not forget that the battery is a key structural element in the electrical circuit of a motorcycle. The least we can do is proper maintenance. Checking the electrolyte level in conventional batteries is important, because a smaller quantity than normal, except that it reduces the amount of particles, with effect, leaves the lead plates exposed and unprotected from oxidation. No matter if the battery is conventional or MF, a preemptive charge on each service can save a lot of trouble. And we must not forget that the battery must be clean of dirt. A little vaseline or grease on the poles, but after they are first connected to the circuit, protects against oxidation and the appearance of scales that can interrupt the flow of current.