Flat battery?

AA patrols carry the latest industry leading battery tester

AA patrols carry the latest industry leading battery tester

AA patrols carry the latest industry leading battery tester

Faulty or flat batteries are one of the most common causes of breakdown. Stop-start or short journeys don't give batteries the opportunity to recharge properly.

There are a few things you can do to prolong the life of your car's battery, but we can also help.

When we attend a vehicle with a flat battery, or suspected flat battery we don't just jump start the vehicle and send you on your way. Our patrols will always carry out a battery test and look for the cause of the problem first.

Reasons for flat batteries

A flat battery is most commonly caused by;

  • a lack of use or vehicle only used for short journeys
  • something has been left on (light(s) or a faulty component is draining the battery
  • a fault with the vehicle's charging system
  • a fault with the battery itself

Short journeys or insufficient use of a vehicle will shorten a battery's total life. This 'under charging' results in 'sulphation' if the battery voltage is allowed to remain below 12.4 volts. Sulphation is the hardening of the lead plates within the battery and it reduces the battery's ability to accept or hold a charge.

If you do only use your car occasionally and for short journeys it's worth investing in an intelligent charger/battery conditioner that can be left connected for long periods without risk of damage to the battery.

Batteries can fail for other reasons too such as, excessive vibration, over charging, corrosion and temperature (extreme heat and cold).

How we deal with battery problems

When we attend a vehicle with a flat battery, or suspected flat battery we don't just jump start the vehicle and send you on your way. Our patrols will always look for the cause. The patrol will;

  • test the battery
  • check the vehicle's charging system
  • check for a vehicle fault that may be draining the battery, and
    ask what sort of use the vehicle gets

AA patrols carry the latest industry leading battery tester which uses Conductance technology to measure the health of a battery. Conductance battery testing has become the industry standard and is used by all of the major motor manufacturers.

Battery testing

For an accurate result a lead acid battery has to be tested in its 'rested state', i.e. before the engine has been started – once the engine has been run, voltage and resistances within the battery will change and this can affect the test result. This means the patrol will always start by carrying out a battery test.

The patrol will connect the tester to the vehicle's battery or remote jump start points and enter the battery details – type and specification – into the tester.

The tester is pre-programmed with data which it compares with the readings from the battery on your vehicle so it can assess the condition.

The battery tester will then display and print the results of the test.

The patrol will still check the charging system and check that nothing is draining the battery to ensure there are no other faults.

The detailed test result will include one of the following statements summarising the condition of the battery.

'Bad cell'

A car battery is made of several separate two volt batteries – called cells – joined together. Cells cannot be replaced individually.

The battery needs replacing as the tester has identified that the battery has a defective cell.

'Replace battery'

The tester has identified that the battery is no longer able to provide the required current and needs replacing.

'Charge and retest'

Ideally the battery should be fully bench charged and retested.

As this is not an option at the roadside the patrol will follow an approved procedure using the vehicle's charging system, an amp-clamp (a non-contact tester which measures current flowing through a cable) and volt meter to measure the battery's ability to accept a charge.

A weak battery is slow to accept a charge, but a good battery will accept a charge more readily. If the readings with the voltmeter and amp-clamp are within specification for the vehicle the original battery test will be repeated to make sure the battery did not just fail the initial test through lack of voltage.

'Good, recharge'

This indicates that the battery is within specification but discharged.

The patrol will check the charging system, check that nothing is draining the battery and if necessary investigate further the cause of the breakdown.

A jump start will almost certainly be required and the patrol will advise a full recharge as soon as practicable using a battery charger/conditioner.

'Good battery'

The battery is within specification and in good condition. The patrol will check the vehicle's charging system and will then investigate the cause of the breakdown.

Replacement batteries

We can supply and fit a new car battery at a time and location that’s convenient for you.

If you do need a new battery an AA Battery Assist technician can supply and fit a new one for you and take the old one away for environmentally-friendly disposal.

(20 September 2013)

 

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