How to Charge a Car Battery with a Charger?
3 Answers
Method for charging a car battery: Connect the positive terminal of the battery to the positive terminal of the power source, and the negative terminal of the battery to the negative terminal of the power source. Below is a related introduction on how to charge a car battery: 1. First, use the initial charging current until bubbles are released from the electrolyte, and the single-cell voltage rises to 2.3—2.4V. Then reduce the current to half of the initial charging current and continue charging until the electrolyte releases intense bubbles, and the voltage remains stable for 3 hours. 2. The total charging time is approximately 45—65 hours. The temperature should be controlled between 35—40°C. If the specific gravity of the electrolyte does not meet the required standard after the initial charging, adjust it using distilled water or an electrolyte with a specific gravity of 1.4. After adjustment, charge for another 2 hours until the specific gravity meets the standard. 3. New batteries often do not reach their full capacity after the first charge, so a discharge cycle should be performed. Discharge at a 20-hour rate (i.e., discharge with a current equal to 1/20 of the rated capacity until the single-cell voltage drops to 1.75V), then recharge until fully charged. If the capacity is still below 90% of the rated capacity after one charge-discharge cycle, perform another charge-discharge cycle.
Just helped my dad recharge his old Passat yesterday. It's actually pretty straightforward but requires attention to details. First, park the car in a well-ventilated area and make sure the engine is completely turned off. Check the battery surface for cracks or leaks while you're at it. My routine is to disconnect the negative cable first, then the positive, and use a small brush to clean any green oxide off the terminals. Next, firmly attach the charger's red clip to the positive terminal and the black clip to a clean metal part in the engine bay. I usually set the charger to slow charge mode, select the 12V setting, and keep the current around 5 amps for safety. Once charging starts, never smoke nearby—I once almost dropped a lighter on it. Stop charging when the battery bubbles reduce or the voltage reaches 14 volts, turning off the charger before removing the clips. In winter, extend charging by half an hour, and avoid high currents with aged batteries to prevent swelling.
Last time my car wouldn't start and I went to the repair shop, the mechanic taught me how to charge it this way: You must use a charger with matching voltage. Cars generally use 12V, while large trucks use 24V. Before connecting, make sure the charger switch is off. Connect the positive terminal to the battery's positive terminal. For the negative terminal, it's best not to connect it directly to the battery's negative terminal as it can cause sparks to fly everywhere; instead, attach it to a metal part of the car frame. If the charger has an automatic mode, just press the button. For manual mode, you'll need to monitor the ammeter yourself. Don't panic if the dashboard lights up during charging, but never start the engine. That time, I charged it for four hours and unplugged it when the battery felt slightly warm to the touch on the side. Remember, ventilation is especially crucial because the battery releases hydrogen gas during charging; charging indoors is like playing with fire. After using the charger, store the cables properly; tangled cables can easily cause a short circuit.
