Is it normal for a car battery to get hot while charging?
4 Answers
When the battery is being charged, the electrolyte will be in a boiling state, so it's natural to feel that the battery is hot when touched by hand, and theoretically there is no risk of explosion. However, if the heating is abnormal, it may cause thermal runaway of the battery, leading to battery swelling. Car battery maintenance methods: 1. Avoid deep discharge. Most of the batteries on the market today are lead-acid batteries, which are structured by inserting positive and negative electrodes into a box filled with sulfuric acid electrolyte. If the battery is deeply discharged, the electrolyte and the plates will undergo a chemical reaction, forming a large amount of lead sulfate. When the lead sulfate reaches a certain level, it will harden into irreversible crystals. 2. Avoid excessively high temperatures. Most car owners only know that batteries are afraid of cold, and that low temperatures can affect battery capacity, making it difficult to start the car. However, excessively high temperatures can be fatal to the battery.
Last time I charged my battery, I encountered a heating issue, which was quite concerning. It's normal for the battery to feel slightly warm during charging, but if it becomes too hot to touch, that's absolutely unacceptable. In such cases, you should immediately disconnect the power and inspect it—it could be due to the charger's current setting being too high or an internal short circuit in the battery. My neighbor, Old Zhang, had his battery swell up because of continuous overheating, and it ended up being completely ruined. The most dangerous scenario is that overheating can lead to leakage or even fire, especially when charging during hot summer days. It's advisable to charge in a well-ventilated area and not exceed 8 hours. If the battery repeatedly overheats, it's best to replace it—safety first, after all.
As someone who frequently tinkers with cars, I believe battery charging heat should be assessed case by case. Feeling slightly warm to the touch right after charging is normal, just like how phones get warm during charging. But if it's too hot to touch, it's likely overcharging. I've seen cases where using incompatible chargers caused batteries to overheat and deform, even leaking electrolyte. In such situations, you must stop charging, let it cool down, and then check if the charger voltage matches. Additionally, aged batteries are more prone to overheating - those over four or five years old should be replaced directly. Remember to open the hood for ventilation during charging to avoid high-temperature hazards.
Last time my car battery got hot while charging, I asked a mechanic and felt relieved. Slight heating is normal, but abnormal overheating should raise alarm. It could be due to excessive charging current or an internal short circuit in the battery. The mechanic said prolonged overheating can reduce battery life and in extreme cases may cause spontaneous combustion. So it's best to monitor during charging and stop immediately if the temperature gets too high. Using a smart charger is recommended as it automatically adjusts the current. If the battery itself is old, heating up is a sign that it's time for a replacement.
