Charging a battery with a charger — safely at home

If the battery has gone flat but is still healthy, a charger lets you recharge it at home. It’s a convenient alternative to driving around town “to charge it”, which rarely charges the battery fully anyway.

Which charger to choose

The most convenient are automatic microprocessor chargers, which set the current themselves and stop charging once full. It’s important that the charger matches the battery type — flooded, EFB or AGM.

How to charge, step by step

1. Set the charger in a dry, ventilated place
2. Connect the positive first, then the negative (or ground)
3. Select the right mode for the battery type
4. Switch the charger on only after connecting the clamps
5. When charged, switch the charger off and disconnect the clamps

What to remember

• Ensure ventilation — batteries can give off gases
• Don’t charge a damaged, leaking battery
• A full charge cycle usually takes several to a dozen-plus hours
• A charger won’t repair a sulphated, worn battery

A charger will top up a healthy battery, but it won’t revive a worn one. If the battery keeps dying after charging, it’s simply tired.

When charging isn’t enough

If the battery goes flat despite charging, shows signs of wear or is a few years old, charging only puts off the problem. Then the solution is replacement.