How to Charge a Car Battery Indoors

by Cameron
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battery charger image by Albert Lozano from

According to Happy Living, a car battery should be recharged if it has been in storage for a long period of time, if it has been accidentally drained or if the battery is aging and simply needs a boost back to heath. Indoor charging is not much different from charging the battery outdoors; however, take precautions when charging a battery indoors as sparks can easily ignite if battery recharging is done improperly.

Step 1

Wear safety glasses. Protect your eyes from possible diluted sulfuric acid solution that can spark in reaction to the battery's flammable hydrogen gas.

Step 2

Place the battery charger on a concrete, flat surface away from flammable materials and wood. Use the charger in a garage or basement where it is away from household furnishings.

Step 3

Place the volt setting of the battery charger on 12 volts and choose a low amp setting that will charge the battery slowly. Slowly charging the car battery will desulfate the crystallization of lead sulphates, providing a higher amperage output return.

Step 4

Select the correct battery-type setting on the charger if applicable. Most modern car batteries use a conventional/low-maintenance battery. Use a compatible AWG gauge extension cord if necessary to reach the garage electrical outlet.

Step 5

Apply the red positive alligator clip to the positive terminal end of the battery first. Place the black negative alligator clip onto the non-painted metal bracket. Activate the charger. Allow the battery to charge for six to eight hours. Never charge the battery over 8 hours (unless directed by battery-charger manual), as it can damage the internal components.

Step 6

Test the battery's voltage with a voltmeter and set its dials on the 0-50 V range. Disconnect the battery charger from the battery. Connect the voltmeter's positive red lead to the battery's positive terminal. Connect the black lead to the negative terminal. Check the voltage level; if the battery has a range of 12.6 to 12.8, the battery is charged. Keep charging the battery if it has a voltage under10 V.

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