A battery is a device consisting of one or more cells that can produce a direct current by converting chemical energy into electrical energy.
A motorcycle battery is made up of a plastic case containing six cells. Each cell is made up of a set of positive and negative plates immersed in a dilute sulfuric acid solution known as electrolyte, and each cell can hold a voltage of around 2.1 direct current (design dependent) volts when fully charged that are linked together. A fully charged battery of about 12.6volts is produced when all six cells are connected together.
Each cell consists of lead plates that carry either a positive or a negative charge. The positive ones are mostly made from lead dioxide and negatively charged ones are typically made from spongy lead. Depending on quality and cost, lead material can be chosen. The plates are arranged positive-negative-positive pattern, with an insulating material to prevent contact between plates. The insulation material is usually treated paper or fiberglass. Battery current capacity is directly related to the number of plates. More the plates or larger the plates, the flow of electricity will be much more.
In a typical cell, all positive plates are connected to each other, as are the negative plated. Further each cell is connected to neighboring cell in series-positive to negative, negative to positive.
For chemical a reaction to happen, an electrolyte which is a mixture of distilled water and sulfuric acid is added. When it reacts with the plates, an electric charge is generated.
As battery discharges, both electrolyte and lead plates undergo a transformation. I.e. electrolyte turns in water and lead plates are coated with lead sulfate eventually battery goes dead. To delay this process, the battery needs to be recharged by an external power source. In this case, the electrical system of the motorcycle is used which can produce higher voltage than the battery, restoring the battery to its original chemical state.
Though they are popular, they have drawbacks such as:-
- They are filled with highly corrosive liquid
- They produce hydrogen gas and require venting
- They require periodic topping up of water as it evaporates which if neglected impacts battery's ability to hold charge.
- They have to be mounted vertically to prevent leakage
Due to these drawbacks, an another type of battery was created known as Valve regulated lead acid or "Sealed maintenance free batteries"
Valve Regulated Lead Acid batteries
Most popular type of VLRA is absorbent glass mat battery or AGM. A major differentiation factor between AGM and conventional battery is that there is no pool electrolyte in the cell. Instead of a paper (or fiberglass) barrier to separate the lead plates in each cell, the AGM uses a Glass-Fiber mat which is made up of glass fiber and a styrene or acrylic binder, filled with electrolyte and stuffed between the plates. When the battery is initially filled, the electrolyte is absorbed and held in suspension by the mat, the electrolyte stays in contact with the plates through capillary action.
Since the glass-fiber mat is very strong, it provides the plates with more support so they can be made of a softer with purer form lead-calcium alloy, thereby increasing the battery's efficiency. Also, as there is no electrolyte, the battery produces more current as compared to conventional battery of a same size. AGM batteries are robust and have better resistance to vibration.
Few advantages of AGM batteries:-
- Virtually no maintenance required
- No water top up required
- No acid leakage
- Mounting can be done in any position
- Hold charge for an extended time period of time
- Resistant to freezing, giving seasonal advantage
While AGM batteries have a lot of pros, but on the other hand it has few cons as well like:-
- They need min 14 volts from the charging system to get charged
- If overcharged, they will get damaged
Cold Cranking Amperage
Cold cranking amps (CCA) is a measurement of the amperage a battery can deliver at 0 ° F for 30 seconds and not drop below 7.2 volts. So a high CCA battery rating is especially important in starting battery applications, and in cold weather.
CA is cranking amps measured at 32°F. This rating is also called marine cranking amps (MCA). Hot cranking amps (HCA) is seldom used any longer but is measured at 80°F.
Battery's Amp Hour Rating
The battery's Amp Hour Rating describes how long the battery will last at a fixed discharge rate. For small motorcycle batteries, the average is generally calculated over a ten-hour period, at 1/10 of the battery's amp rating. For example, a 14 Amp-Hour rating means the battery can discharge 1.4 amps for 10 hours.
RC or reserve capacity is the number of minutes a fully charged battery at 80°F will discharge 25 amps until the battery drops below 10.5 volts. In a nut shell, a battery performs best at high CCA and amp hour rating.
Understanding battery designation
Types of Terminal
Terminal shapes vary from one battery to another.By identifying the correct replacemnt battery from the listing in this book, you are assured of the proper terminal configuration. For custom appliances, refer to the following chart to identify terminal shape and corresponding batteries.
How to choose a battery
It is suggested to buy a battery with the greatest reserve capacity or amp hour rating possible. Of course the physical size, cable hook up and terminal type must be a consideration. Also, the type of battery should be a gel cell or an absorbed glass mat (AGM) rather than a wet cell/conventional lead acid battery if the application is in a harsher environment, or the battery is not going to receive regular maintenance and charging.
Freshness of a new battery is very important. The longer a battery sits and not recharged the more damaging sulfation will build up on the plates. So, buy a battery which is manufactured recently.
Testing a battery
There are number of ways batteries are tested, please visit our testing and certification page to know more.
There are few points that needs to be considered when storing batteries
1. Periodic check
- Check conventional batteries every month
- Check AGM batteries every three months
If circuit voltage shows low state of charge, charge the battery
2. Temperature : Ideal temperature while storing should range better 60° F to 80° F. Below or above this range requires frequent check-up/inspection/charging
3. FIFO: Adopt first in first out method to keep proper rotation of batteries