The Secret To Extending Battery Life & Preventing Sulfation


Properly charging rechargeable batteries after each discharge is essential for maximizing their lifespan, especially for lead acid (flooded cell, AGM, Gel) batteries. This article explains the science behind battery sulfation and how to prevent it.

Understanding Battery Sulfation

What is Battery Sulfation?

Sulfation occurs when lead sulfate crystals build up on the battery plates. This is a natural part of the battery’s chemical process, but excessive sulfation can significantly reduce battery performance and lifespan.

How Does Sulfation Affect Batteries?

  • Longer Charging Times: Sulfation impedes the chemical-to-electrical conversion.
  • Excessive Heat Build-Up: Heat is generated as the battery struggles to charge.
  • Shorter Running Times: The battery holds less charge, leading to reduced performance.
  • Complete Battery Failure: Severe sulfation can render a battery unusable.

The Science Behind Sulfation

Discharge and Charge Reactions

During discharge, the following reactions occur in a lead acid cell:

  • Negative Plate: Pb + H2SO4 → PbSO4 + 2electrons
  • Positive Plate: PbO + H2SO4 + 2electrons → PbSO4

Both reactions produce lead sulfate (PbSO4) that deposits on the plates. During charging, these reactions reverse, converting lead sulfate back into lead and lead oxide.

Why Complete Charging is Crucial

If not enough electrons are supplied during charging, lead sulfate remains on the plates. Over time, this sulfate layer becomes hard and significantly reduces the battery’s capacity.

Preventing Battery Sulfation

Proper Charging Practices

  1. Ensure Full Charges: Always fully recharge your battery after each use to prevent sulfate build-up.
  2. Temperature Control: Store and charge batteries in cool environments (below 75°F) to minimize self-discharge and sulfation.

Regular Maintenance

  • Monitor Voltage: Keep the battery voltage above 12.4 volts to prevent sulfation.
  • Avoid Overcharging: Overcharging can cause excessive heat and damage, leading to sulfation.

Special Considerations for AGM & Gel Batteries

These types are particularly susceptible to permanent sulfation. Ensure they are charged properly to prevent irreversible damage.

Reversing Battery Sulfation

Reversible vs. Permanent Sulfation

  • Reversible Sulfation: Can be corrected by an overcharge using a regulated current of about 200mA for 24 hours, raising the terminal voltage to 2.50-2.66V/cell.
  • Permanent Sulfation: Occurs when a battery has been left on a low charge for an extended period. It is often irreversible, especially in AGM and Gel cells.

Advanced Techniques

  • Temperature Adjustment: Increasing the battery temperature to 122-140°F (50-60°C) during corrective charging can help dissolve the crystals.
  • Anti-Sulfation Devices: These devices apply pulses to battery terminals to prevent and reverse sulfation. However, they are not always effective and should be used with caution.


Preventing battery sulfation is crucial for maintaining the performance and lifespan of your lead acid batteries. By following proper charging practices, maintaining optimal storage conditions, and using preventive measures, you can significantly extend the life of your batteries and ensure they operate efficiently.

Bogart Engineering’s SC-2030, when used with a TM-2030, accurately measures the Amp-hrs returned to the battery during charging and compares it to the previous discharge Amp-hrs and sustains the charging process until the 100%  of the discharge Amp-hrs are returned.  It is also possible to configure the SC-2030 so that a specific amount of excess charge is delivered, to account for the inefficiencies in the charging process.  By implementing an Amp-hrs based charging on a new set of batteries, it is possible to extend battery life by 15-25%.

To our knowledge, the TM-2030/SC-2030 system is the only one in the market with Amp-hrs based charging termination feature.  Parameters specific to Amp-hrs based charging are set in P15 (voltage limit), P21 (current limit) and P20 (excess charge % relative to previous discharge).

To purchase the Trimetric Battery Monitor & Solar Charger kit visit our store