This is the last installment of our three part series on batteries. In this article we will explain the best way to charge your battery to ensure your battery will last as long as it should.
Battery charging is one of those things that most people give very little consideration to. Unfortunately poor battery charging techniques are responsible for the early death of most batteries. For this article, the charging explained is for lead acid and AGM as well as calcium batteries (calcium batteries are primarily just lead acid batteries.)
Battery chargers come in all different shapes sizes and price brackets. Cheap battery chargers are unfortunately probably one of the biggest killers of batteries. The main reason they kill batteries is because they do not have the ability to regulate the amount of charge going into the battery. If the battery is left unattended and on too long then the battery will be overcharged and irreversible damage will be done.
The most popular and effective battery chargers on the market are the ones that have the ability to give a three stage charge. These days the three stages can be split up into as many as 7 stages, however it is pretty much the same philosophy however they have more stages for the battery to cool down and level out the state of charge before carrying on with the charging process.
These battery chargers are pretty expensive compared to the cheaper ones, but when you consider how much outlay you make for a decent battery and the extended life you will get out of it by following good battery charging practices the initial price will be offset in a couple of years. Not to mention the increased capacities that your battery will be able to give you.
Three stage chargers work in this way:
The first stage of 3-stage battery charging. Current is sent to batteries at the maximum safe rate they will accept until voltage rises to near (80-90%) of full charge level. Voltages at this stage typically range from 10.5 volts to 15 volts. There is no “correct” voltage for bulk charging.
The 2nd stage of 3-stage battery charging. Voltage remains constant and current gradually tapers off as internal resistance increases during charging. It is during this stage that the charger puts out maximum voltage. Voltages at this stage are typically around 14.2 to 15.5 volts.
The 3rd stage of 3-stage battery charging. After batteries reach full charge, charging voltage is reduced to a lower level (typically 12.8 to 13.2 volts) to reduce gassing and prolong battery life. This is often referred to as a maintenance or trickle charge, since its main purpose is to keep an already charged battery from discharging.