The AER -12VN regulator overcomes the counter-voltage by using sophisticated micro-processor technology.

 

> It measures the true battery status  -  voltage and temperature - at the battery terminals. Using this information and a proprietary charge algorithm, it controls the charging voltage.

 

> By measuring directly at the battery, the AER-12VN is not mislead by circuit losses. It compensates for these and applies the correct voltage required at all times

 

> There is no risk of damage and sulphation is prevented.

The electrical system in a truck is said to be a 12 volt system, but this is slightly misleading. The charging system in most vehicles will generally produce a voltage between 13.5 and 14.4 volts while the engine is running.  It has to generate more voltage than the battery's rated voltage to overcome the internal resistance of the battery.  This may seem strange, but the current needed to recharge the battery would not flow at all if the charging system's output voltage was the same as the battery voltage. A greater difference of potential (voltage) between the battery's voltage and the alternator's output voltage will provide a faster charging rate. 

 

To charge a battery you need to overcome the battery's counter voltage. This creates a resistance which increases as the charging proceeds - so the current drops to a minimal level long before the battery is fully charged. This is caused by poor diffusion of electrically charged ions within the battery cells.  The sulphuric acid electrolyte can become fully restored in the vicinity of the lead plates, but this benefit is not rapidly spread to the bulk of the electrolyte in the cells.

 

Discharging a battery reduces the specific gravity (S.G.) or weight of the acid electrolyte. Recharging has the opposite effect, increasing the S.G.  With a rapid discharge - such as engine starting - the electrolyte is only affected in the immediate area to the plated. The slow diffusion effect prevents the entire charge of electrolyte from becoming affected - in the short term. Normal charging can restore the battery quite easily.  With a slow discharge, the entire volume of electrolyte is affected. When you come to recharge, the slow diffusion effect is working against you.  The acid near the plates is easily restored (S.G. increased) but the benefit is localized . The battery gives the "impression" that it is fully charged when it is not.  Simple regulators cannot recognize this phenomenon as they maintain a fixed voltage, the charging current reduces to a trickle when faced with increased resistance.
    
Sulphation is caused by inadequate charging at too low a voltage.   An incomplete chemical reaction in the battery cells causes harmful deposits of lead sulphate to form on the active surface of the plates.  These deposits reduce charging capacity, by inhibiting current flow and increasing the "diffusion resistance" - creating a vicious circle of damage which is usually permanent.