What causes battery failure

Battery life and performance - Average battery life has become shorter as energy requirements have increased. Two phrases I hear most often are "my battery won't take a charge, and my battery won't hold a charge". Only 30% of batteries sold today reach the 48-month mark. In fact 80% of all battery failure is related to sulphation build-up. This build up occurs when the sulfur molecules in the electrolyte (battery acid) become so deeply discharged that they begin to coat the battery's lead plates. Before long the plates become so coated that the battery dies. The causes of sulfation are numerous. Let me list some for you.

  • Batteries sit too long between charges. As little as 24 hours in hot weather and several days in cooler weather.
  • Battery is stored without some type of energy input.
  • "Deep cycling" an engine starting battery. Remember these batteries can't stand deep discharge.
  • Undercharging of a battery to only 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry not reactivated by the incompleted charging cycle.
  • Heat of 100 plus F., increases internal discharge. As temperatures increase so does internal discharge. A new fully charged battery left sitting 24 hours a day at 110 degrees F for 30 days would most likely not start an engine.
  • Low electrolyte level - battery plates exposed to air will immediately sulfate.
  • Incorrect charging levels and settings. Most cheap battery chargers can do more harm than good. See the section on battery charging.
  • Cold weather is also hard on the battery. The chemistry does not make the same amount of energy as a warm battery. A deeply discharged battery can freeze solid in sub zero weather.
  • Parasitic drain is a load put on a battery with the key off. More info on parasitic drain will follow in this document.

In most cases, you can remove the sulfation of the plates and release the sulfur back into the electrolyte by using high frequency electric pulses.  A low hydrometer reading indicates that the sulfuric acid has left the water solution electrolyte and attached itself to the plates.  Releasing the sulphur back into the electrolyte will renew the battery.  Chemicals can also be used to de-sulphate the plates.

Once the plates are clean and free of sulphur, and the electrolyte readings with a hydrometer are correct, you may get another 5 years out of the battery.