This is the second instalment of a three part series on batteries. To ensure you get the right battery for the job, this article will take you through the different battery types and their intended application.
Batteries are a part of our life whether it’s in the car or boat, and in both applications we rely on them a hell of a lot. In a boat they can be a matter of life and death so having the right battery and one that is reliable and in good condition is essential.
There are different types of batteries and they all have different uses, however the most common type for boats and cars is a 12 volt lead acid battery. The other types are Gel Cell or AGM, Maintenance free sealed batteries, calcium batteries which is basically just another type of lead acid and then there are the super expensive and light weight Lithium range of batteries
For this article we will be looking at only lead acid type 12 volt batteries, but most of the information will be applicable to the other types of batteries, except the Lithium batteries, they operate under their own set of unique rules and special battery chargers so we will leave them for a time when they are a bit more affordable.
There are three main types of 12 volt lead acid batteries:
Automotive or Cranking Batteries
These batteries, as the name suggests, are for starting motors. They are designed to have a large draw from a starter motor for a short period of time. Once the motor is running the alternator will quickly restore the used voltage to the battery.
Deep cycle batteries are basically designed to deliver power over a long period. These batteries are able to be discharged a lot more than a cranking battery and not suffer the adverse or shortened life that a cranking battery would if continuously used as a power source.
Marine batteries are a type of hybrid between a deep cycle battery and a cranking battery. They are designed to be used as a cranking battery to start the out board or inboard motor and a deep cycle battery to run equipment like bilge pumps, echo sounders, GPS units as well as all of the other accessories we run while the motor is switched off.
Why is using the correct battery type so important?
Trying to use batteries for applications outside of what they were designed to do will dramatically shorten the life of the battery. For instance if you were to try and use a cranking battery as a deep cycle battery to run a fridge or electric motor, the battery would probably be dead before it has been recharged thirty times.
Likewise if you were to try and use a deep cycle battery as a cranking battery, life of the battery would be drastically reduced. In the event of an emergency however, do not think twice about starting a motor off a deep cycle battery as it will handle this job but it was never designed to do it over and over again.
Buying a battery suited to the application may seem expensive at the time but if you use the wrong battery then chances are it will be costing you a lot more in the long run.
Getting the right battery for the required job is really important, but unfortunately with batteries it doesn’t stop there. Battery maintenance is critical to keep your battery in its best possible condition. The most basic thing to remember is to keep your battery topped up with distilled water so that the plates are covered at all times. If these plates are exposed to air they will become subject to sulphation which will effectively lock and stop the battery working to full capacity. Never use anything other than distilled water and do not top up batteries with battery electrolyte (acid). The electrolyte or acid will not evaporate as it is only the water content that evaporates so there is no need to replace it unless the acid has actually spilled out of the battery.