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Car batteries are the accumulated chemical energy stored in a container and released in the form of electricity. The battery measurements are made with the VOLT, AMPERE and AMPERE / HOUR characteristics using the voltmeter. On car batteries, the volt is always 12 and the other two technical specifications depend on the size of the battery.

How and when do we measure the voltmeter?

The battery is correctly measured when left disconnected for 24 hours. However, making a measurement after 3 hours (with the key in the off position) and if the current demand from the vehicle circuit does not exceed 1% of the total Ampere of the battery capacity, we can get a fairly clear indication. For the measurement, we need a multimeter at the DC measuring position.

The measurements that must give us a good battery under load (within a circuit on the car) are:

  • The off-state voltage must be> 12 - 12.5 V (battery is at a standstill)
  • The voltage with the engine must be> 13.4 - 14.2 V (the battery is charged)
  • The voltage during starter operation must be> 9.5 V (the battery provides power to start the engine)The causes that can make a battery useless

a) Discharge

Because of the solubility of lead in water and other factors (impurities in the solution, etc.), the battery gradually loses energy stored inside it.

If we leave a battery for a long time empty or a little charged than a chemical reaction in its plates forms lead oxides crystalline insoluble. Lead oxides gradually fill the surface of the lead plates by blocking the chemical reactions that store and deliver electricity.

b) Mistreatment and vibration

The activated lead plates inside the battery have rows of slots in which the lead oxides are pressed. Thus, the batteries become lighter and the surface of the plates with the electrolyte increases (so does the capacity). If the lead oxides break off (from mist and vibrations) they will fall to the bottom of the battery causing a short circuit between the elements.

At Car Batteries Horncastle we can provide you with information, change your old batteries, provide you new ones and help you find the ones that are compatible with your car model so you can choose the ideal one for yourself.

Your Simon Rawdon Tyres!