Most Car batteries only last about 4-5 years. I would say that your battery
is just about reached its useful life span.
Its cheap piece of mind to replace them after 4 years.
To check a battery you should really have a load test done on it, most
places generally do not charge for this, it only takes them 5 minutes.
But you can do a little test on it yourself.
The battery voltage car not running should be 12 volts or close to it. If
its 11.0 volts or under, its had it.
When the car is running the voltage across the terminals should be about
13.6 - 14 volts.
If the car is difficult to start or the lights really dim when you operate
the starter this is a sign that the battery is getting weak.
Hope this helps.
What voltage/current should my 1999 X reg 1.8 petrol Zetec focus be in
the region of ? I would like to check myself before helfords (or
similar) charge me for something I do not need.