Excess gassing kills batteries

Manual bulk (boost) causes gassing. Bulk charging will be automatically terminated as the battery cells reach their charged capacity.

High ripple kills VRLA batteries

DC Current Ripple creates heat within a battery which VRLA batteries cannot dissipate. VRLA’s should be charged with a charger that has <5% Ripple. By smoothing the output or switching at high frequency the ripple can be decreased.

High temperature kills batteries.

  • 95% of engines failing to start are due to poor battery condition
  • A battery is a chemical means of storing electricity
  • Batteries should be charged at 20C or 68F 
  • Example on 12V Lead Acid Batteries:
  • Float = 13.6V Boost = 14.1V
  • At 50°C this equals 0.54 volts, the same effect as being in bulk
  • 50°C – 20°C = 30 x .003mVx 6 = 0.54  
  • 13.6 v – 0.54 =  13.06v @ 50°C

Stratification kills batteries

This is where a long period of float charge has occurred and the electrolyte separates. Applying a Bulk (equalise) voltage is required to prevent separation of the electrolyte.

How to prevent Stratification.

A fully charged battery is connected to a load (light bulb) and the chemical reaction between sulphuric acid and the lead plates produces the electricity to light the bulb. This chemical reaction also begins to coat both positive and negative plates with a substance called lead sulphate also known as sulphation (shown as a yellow build-up on plates). 

This build-up of lead sulphate is normal during a discharge cycle. As the battery continues to discharge, lead sulphate coats more and more of the plates and battery voltage begins to decrease.

During the battery recharge cycle lead sulphate (sulphation) begins to reconvert to lead and sulphuric acid.

At float charging only, the charger will maintain a full charge, reduce gassing and water loss. However, this lower voltage does not provide enough gassing to prevent a battery condition called Battery Stratification

Battery Stratification is caused by the fact that the electrolyte in the battery is a mixture of water and acid and, like all mixtures, one component, the acid, is heavier than water. Therefore, acid will begin to settle and concentrate at the bottom of the battery.

This higher concentration of acid at the bottom of the battery causes additional build-up of lead sulphate, which reduces battery storage capacity and battery life. In order to prevent Battery Stratification, an Equalisation must be applied periodically.