The gauge may show a high charging rate at first, but this drops gradually as the battery becomes charged. ) will show that the battery is being charged. Clamp the negative (-) lead, usually black, to the (+) lead from the charger, usually coloured red, to the positive battery post. Leave a trough cover on, unless the charging rate is high. However, if the car has an alternator, disconnect the batteryīeforehand: otherwise some alternators - generally the older type - can be damaged.Ĭaps are fitted, remove them for ventilation. If there is a power point handy, the battery can be left in the car, so long as the charge rate is only 3 or 4 amps. Level before connecting the battery to the charger. ) to see how much capacity is left in the battery, and using a battery charger to top up its charge when necessary. The answer in all these cases is frequent testing with a

, because the alternator produces more electricity and charges better at low Failure is more common on cars equipped with a dynamo rather than an There are also causes other than short trips and cold weather which can affect the state of your battery. As the battery nears full discharge, the lights gradually grow dimmer and finally go out altogether.

Theoretically, a fully charged battery, without taking in current from theįor about ten minutes, or the headlights for eight hours, and a heated rear window for 12 hours. The loads imposed on your battery may be gauged from the amount of current used by the various electrical components: headlights take about 8 to 10 amps, a heated rear window about the same.

Fast charging, however, is undesirable as it can buckle the The higher the charge output, the faster a flat battery is recharged. An average car battery has a capacity of around 48 amp hours which means that, fully charged, it delivers 1 amp for 48 hours, 2 amps for 24 hours, 8 amps for 6 hours and so on.Ī basic charger usually charges at around 2 amps - and so needs 24 hours to deliver the 48 amps needed to fully charge a flat, 48 amp hour battery.īut there is a wide range of chargers with different charge rates on the market - from 2 to 10 amps.

Cen tech heavy duty battery charger