Sulfation, is the number one cause of early failures of lead-acid, sealed AGM or flooded batteries.
On The Lake gives some information:
"Have you ever had a battery that seems to work well but dies much more quickly than expected? The problem may be a battery that is heavily sulfated, often the result of only light use (being discharged by only 15% or so). The sulfuric acid has become concentrated on the bottom of the battery and sulfate crystals have begun to form. And even though a multi-meter will indicate that all is well in terms of voltage, the capacity of the battery has become severely reduced. Sure, the battery will work just fine, but it will die much sooner than normal. There are certain chargers that have a setting that will temporarily boost the charging voltage for a brief period of time, causing a mixing of the electrolyte, and dissolving the crystals. The process is called equalization and can be done, depending on the manufacturer, about once a year. But beware: this should only be done on wet cell batteries; this same process can ruin other types. And you will need to make sure that you disconnect the batteries from the electrical system to prevent the higher voltage from damaging other equipment."
Causes of battery sulfation (with information ofRolls Technical Support):
- Batteries sit too long between charges.
- Battery is stored without some type of energy input.
- Undercharging of a battery to only 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry not reactivated by not completing the charging cycle.
- Low electrolyte level - battery plates exposed to air will immediately sulfate.
- Incorrect charging levels and settings.
- The longer a battery sits and is not re-charged the more damaging sulfation build up there may be on the plates.