Written on February 8, 2016 at 1:20 pm
Just as with any other industry specialist, with what we do here at Manbat comes our own very special language. For many suppliers, distributors and fitters the terms we use to talk about batteries are highly familiar. Others, however, may not be quite as knowledgeable. For example, do you know you’re electrodes from your electrolytes? Can you explain what cold cranking amps are?
We’ve put together an A-Z of all things battery to help you know your battery essentials and learn a fact or two along the way.
In this edition, we look at A, B and C.
The term AGM means Absorbed Glass Mat. Unlike with traditional batteries which contain reservoirs of acid, AGM batteries contain glass fibre mat soaked in electrolyte as a replacement to the typical spacer between cells. The amount of electrolyte is just sufficient to keep the mat wet. Because there is no excess liquid, the electrolyte will not escape even if the battery is split or punctured.
The glass mat is also designed to prevent evaporation, meaning that AGM batteries do not need topping up. As a result, the batteries can be completely sealed, making them ideal for use in portable applications.
During the discharge of an AGM battery, Hydrogen gas is formed. In order to prevent this from building up and causing problems, Calcium – which absorbs the gas – is typically added to the plates. It is important to remember that AGM batteries are optimised for slow discharge.
Another advantage of AGM batteries is that the vertical movement of electrolyteis prevented by the mats. In a traditional lead acid battery, the heavier acid molecules had a tendency to sink to the bottom if the battery was stored, eventually causing damage. This effect, known as stratification, also caused the acid to separate and a layer of water to be formed, which could cause batteries to freeze in cold conditions. The AGM design eliminates such problems, making them less likely to fail in cold conditions.
Image source http://articles.sae.org/10667/
Whether it’s for a car, a watch or even a toy, there are few people who do not know what a battery is and what it looks like. Admittedly, each of the above examples are very different in appearance, but ultimately they all have the same purpose and function in a similar way. But have you ever thought about just what a battery actually is? Let’s have a look.
In a dictionary, the most basic definition of a battery is:
“A container consisting of one or more cells, in which chemical energy is converted into electricity and used as a source of power.”
Each cell within a battery has a positive terminal known as a cathode and a negative terminal called the anode. The terminal marked positive is at a higher electrical potential energy than the terminal marked negative.
When the battery is connected to an external circuit, electrons flow from the negative terminal and deliver energy to an external device. During this process, electrolytes are able to move as ions within, allowing the chemical reactions to be completed at the separate terminals and so deliver energy to the external circuit.
It is the movement of those ions within the battery which allows current to flow out of the battery to perform work. Although the term battery technically means a device with multiple cells, single cells are also popularly called batteries.
Cold cranking amperes (CCA) refers to the amount of current a battery can provide at 0 °F (−18 °C). The rating is defined as the current a lead-acid battery at that temperature can deliver for 30 seconds and maintain at least 1.2 volts per cell – that is, 7.2 volts for a 12-volt battery.
It is a relatively demanding test and is the most widely used cranking measurement for comparison purposes.
Measuring cold cranking amps gives a good idea of what can be expected from a battery in some of the worst conditions possible for starting a vehicle. It should be noted, however, that whilst there are instances where someone may need to start a vehicle in temperatures colder than 0°F or crank an engine for longer than 30 seconds, these are generally exceptions and not representative of typical usage. Regardless, the CCA rating for a battery is still an important performance indicator that offers a general idea of how a battery is designed to perform in the most demanding of conditions.
At Manbat, we are experts in automotive batteries. To learn more about the technical specifications of our products along with a wealth of battery related information, visit the technical section of our website. Be sure to also stay up to date with our latest news, where we frequently publish interesting and informative battery related articles.