How to know when to replace your car battery? Is it a maintenance type or maintenance free? How to maintain your car battery to avoid battery draining?
Most of us did not care about the battery maintenance. Even if you have a maintenance free does not mean that you dont need to take a look at it once in a while.
The majority of batteries now available are grouped as ‘maintenance free batteries’. This implies that a little attention is required during the life of the battery.
Earlier batteries and some heavier type batteries still require the electrolyte level to be checked and topped up periodically (monthly).
Battery posts are still a little prone to corrosion and hence the usual service of cleaning with hot water if appropriate and the application of petroleum jelly or proprietary terminal grease are still recommended.
Ensuring that the battery case and, in particular, the top remains clean, will help to reduce the rate of self-discharge.
The state of charge of a battery is very important and, in general, it is not advisable to allow the state of charge falling below 70% for long periods because the sulphate on the plates can harden, making recharging difficult.
If a battery is to be stored for a long period (more than a few weeks), then it must be recharged every so often to prevent it from becoming sulphated.
Recommendations vary but are charge every six weeks is a reasonable suggestion.
MAINTENANCE FREE BATTERIES
Some maintenance-free batteries incorporate a built-in hydrometer to indicate the state of charge and condition of the battery.
The hydrometer is color coded.
* A green color indicates that the battery is charged and serviceable.
* A green–black or black color indicates that the battery requires recharging.
* A yellow color or white indicates that the battery is faulty.
Where a yellow hydrometer indicates that the battery should not be recharged or tested, and the use of jumpleads for starting should not be carried out.
A new battery should be fitted and the alternator checked for correct operation.
Battery charging can be described as slow or fast.
Slow charging is best but in an emergency a fast charge is acceptable.
When recharging, a battery should ideally be disconnected from the vehicle electrical systems.
There are two types of battery charger: the bench charger, which has a current output of up to about 10 A and the fast charger, which can recharge a battery in about 30 minutes, with a current of up to 50 A.
The automobile battery is used as a source of energy in the vehicle when the engine and the alternator do not run. The lead-acid battery has been proved to be the most suitable battery for automobile use. This is particularly suitable because the cost of the battery is low and taken into account.
Requirements of the vehicle battery
The battery has various numbers of requirements, which are listed as follows:
To provide power storage and to be able to supply it quickly enough for operating the vehicle starter motor.
To allow the use of parking lights for a reasonable time.
To allow operation of accessories when the engine is not running.
To act as a swamp to damp out fluctuations of system voltage.
To allow dynamic memory and alarm systems to remain active when the vehicle is left for a period of time.
Positioning the vehicle battery
Several basic points should be considered when choosing the location for the vehicle battery:
Weight distribution of vehicle components.
Proximity to the starter to reduce cable length.
Protection against contamination.
These issues will vary with the type of vehicle, intended use, average operating temperature etc. Extreme temperature conditions may require either a battery heater or a cooling fan. The potential build-up of gases from the battery may also be considered.
The basic construction of a 12 V lead acid battery consists of
Six cells connected in series: Each cell, producing about 2V, is housed in an individual compartment within a polypropylene; Figure shows a cut-away battery showing the main component parts.
The active material is held in grids or baskets to form the positive and negative plates.
Separators made from a micro porous plastic insulate these plates from each other. The grids, connecting strips and the battery posts are made from a lead alloy.
The characteristics or rating of a particular battery are determined by how much current it can produce and how long it can sustain this current.
The rate at which a battery can produce current is determined by the speed of the chemical reaction.
This in turn is determined by a number of factors:
– Surface area of the plates.
– Electrolyte strength.
– Current demanded.
Any electrical device can suffer from two main faults;
These are either open circuit or short circuit.
A battery can also suffer from other problems, such as low charge or low capacity.
Often a problem can be traced to another part of the vehicle such as the charging system.
Repairing modern batteries is not possible.
Most of the problems will require the battery to be replaced.
In the case of sulphation it is sometimes possible to bring the battery back to life with a very long low current charge. A fortieth of the ampere hour capacity or about a 1/200 of the cold start performance, for about 50 hours, is an appropriate rate.