What, When, Why: Pulse Chargers for automotive batteries

An automotive battery, if left unused over time, starts losing its charge. This happens as the electrolyte in the battery, which is sulfuric acid, keeps reacting with the plates inside the battery acting as cathode and anode. This leads to formation of lead sulfate. Since the battery is not being used, it is not being recharged either. This leads to these sulfate molecules to form crystals on battery terminals. This phenomenon is called Sulfation. This prevents the battery from being fully charged and therefore deliver less power than its capacity. A pulse charger is brought into picture at this point to ensure sulfate crystals can be removed from the battery terminals, making battery revival possible.

Q.How does a pulse charger work?

A pulse charger feeds a series of voltage or current pulses into a decaying battery. These pulses carry DC current and have a strictly-controlled rise time (time taken by a signal to change from specified low value to specified high value), pulse width, frequency and amplitude. A pulse charger is said to work with both regular and valve-regulated batteries.

Q.How does a pulse charger reduce sulfation?

By sending current in pulses, a pulse charger can charge a battery by applying high, instantaneous voltages without overheating the battery. This leads to breaking down of sulfate crystals, thereby increasing a battery's service life.

Q.Are there different types of pulse chargers?

Yes, there are two major types of pulse chargers. The first type is the regular type where upon connecting with the battery, the charger uses pulses to check the state the battery is in, then uses constant current charging for the initial phase and switches to pulse charging later to maintain the charge. The other type consists of chargers using negative pulse charging (also called reflex or burp charging). These chargers use positive pulses with brief negative pulses between positive ones to charge the battery. However, neither charging method is better than the other.

Q.How can I prevent battery sulfation?

The only way of preventing sulfation is to let your car's battery charge fully. If the battery is not fully charged, the lead sulfate inside it will start taking crystalline shape at the battery terminals, leading to sulfation. The worst part about sulfation is even though you can get rid of sulfation, the process itself cannot be reversed. This means reduced electrical capacity of the battery.