Virtual Mechanic

The battery

PURPOSE
The battery is designed to store power and deliver power to all accessories.  Also to receive charge from the alternator.  Batteries are only as good as their connections and connections on the battery poles should not have any white powder or corrosion built up.  This is a problem.  The purpose of the battery is to hold current, receive charge from the alternator and deliver power to all accessories.  Batteries 20 years ago would last around 10 years.  Batteries today, on average, last somewhere between 18-24 months.  If you’re lucky the battery will last 4 or 5 years, but this is an isolated scenario.  Batteries don’t last long as they are designed differently, but still maintain a high price.

THINGS TO LOOK FOR
A battery may be no maintenance, low maintenance or maintenance.  The best one is a maintenance battery with the screw tops so that you can check the water level.  Most batteries will take normal water but if unsure of the quality of the water, then just to be on the safe side, use distilled water.  Don’t over fill or under fill a battery.  The best way to check a battery is to make sure that the water level is always over the plates.  If one cell is descending faster than the other this indicates that the battery is on the way out.  If the battery is vaporising and causing the terminals or poles to corrode with white powder, this is an indication that the battery is over working, either getting to the end of its life or being overcharged by the alternator.  A battery is designed to receive a charge rate of 13.3-14.2.  The preferred charge rate is 13.8-14.2 but that only applies to a very good charging system.  Batteries are only as good as the power they receive and the connections.  Batteries must be secure and held down by a battery clamp.  If not, then the battery may move around and cause an under bonnet fire.  When checking the battery take care not to accidentally put a spanner on the positive connection and earth as the battery may blow up in your face.

IS IT EXPENSIVE TO REPAIR?
Batteries vary, depending on the make and model..  The best battery to buy is one with a 2 year warranty.  Batteries do have a higher mortality rate than the average vehicle component.  Remember to keep your receipt and don’t expect the battery to last  any more than 3 years.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If fitting a battery, be very careful to make sure the terminals are in the exact location as the old battery.  These terminals vary from battery to battery according to the manufacturer and the make and model.  These terminals are situated at different locations to allow the connections to be connected with slack.  Remember, if fitting a battery and you find the positive or negative terminal very tight or just making it to the battery pole, when the engine revs, the engine will move and the battery cable will become tight and move around and the battery pole may be yanked out of the battery causing acid to pour everywhere.