Battery chargers: fixing the weakest link

• Batteries consist of individual battery cells connected in series or parallel or in a combination of both to obtain the required voltage and capacity. Cells connected in series have positive terminals connected to negative terminals while those connected in parallel have like terminals connected to each other (i.e. negative to negative and positive to positive). Since no manufacturing process is a hundred percent efficient, batteries, like other manufactured products, have variations between the capacities of each individual cell. This variation tends to increase as the battery usage racks up. Given that the cells in the chain making up the battery are not all exactly identical the battery is only as strong as the weakest cell in the chain.

• Unlike the popular tv show though we can’t simply wave goodbye and dismiss the weakest link, we need to find a way of trying to keep the cells all operating at their peak capacity. In order to correct cell capacity differences, a process called ‘equalizing’ can be used when charging batteries, where the battery charger, for short periods, raises the charging voltage for the whole battery allowing all cells, even the weakest link, to accept more current than usual. The normal charging voltage delivered by a battery charger is referred to as the ‘float’ voltage. Float chargers usually work at a low voltage thereby keeping the charging current low and consequently reducing the damaging effects brought about by high current overcharging.

• When buying an industrial battery charger it pays to carefully assess your needs and current usage to determine which charger type will match your requirements. In the world of battery chargers, capacity reigns over efficiency. Capacity is measured in Ampere-hours. An Ampere-hour (Ah) is a unit of electric charge equal to the electric charge transferred by a steady current of one ampere for one hour. Small capacity chargers generally cost less than larger capacity chargers. Charger prices also vary depending on whether they are one phase or three phase devices.

• Once the charger has been purchased additional factors to consider are charger servicing, placement and staff training. Chargers should be located in a suitable position where they can easily be connected and serviced. The manufacturer can provide battery charger servicing, inspection, maintenance and safety recommendations. In an industrial setting only authorized staff who have been trained in the proper use of the charger should be allowed to operate it. It is also essential to engage a professional battery charger service provider to ensure that the charger operates efficiently for as long as possible.