A portable car battery charger is usually considered to be one that has a carry handle and weighs up to 50 pounds. They can come with or without wheels. Charging current can range from one Amp for a trickle charger, up to 200 Amps for a booster and charger combination. Here’s how to use a portable car batter charger.
Dirty, corroded terminals impede efficient flow of current from the battery to the cables and from charging clamps to the battery. Use a fairly soft bristled wire brush and scrub the battery terminals with a mixture of baking soda and water. The baking soda will neutralize any acid that has accumulated on the terminals. Rinse thoroughly.
The order in which you connect the car battery cables when charging a flat or low battery isn’t as important as when jump starting, but it is good practice to use the same order as when jumping. Make sure the charger is unplugged from the power source. Connect the positive cable first then connect the negative cable. Make sure the connections are good and strong.
Most battery chargers have selectable charge rates. Keep in mind that the higher the charge rate, the higher the internal battery temperature will become and the quicker your battery is going to degrade. Choose a midrange charge level if possible. 50 Amps is considered the maximum rate a battery should be charged at. Use this if you’re in something of a hurry. If you have all night, use a five or ten Amp charge rate to maximize battery life and ensure a complete, deep charge is accomplished.
Once the cables are connected and the charge rate is set, plug the charger in and turn it on. Remove the vent caps so that explosive hydrogen gas doesn’t build up in the battery cells.
When using a portable car battery charger, if you keep the above information in mind, you will be able to safely charge your car battery.