How to Fix a Swollen Battery?
3 Answers
A swollen battery cannot be repaired. Here is relevant information: 1. Causes of battery swelling: In valve-regulated sealed lead-acid batteries during charging, especially in series battery packs, overcharging can lead to poor internal gas recombination in low-quality batteries, resulting in bulging. Setting the float voltage too high or using excessive charging current accelerates oxygen evolution on the positive plate, which cannot recombine at the negative plate in time. Meanwhile, the battery temperature rises rapidly. If venting is delayed and pressure builds up, the valve-regulated sealed lead-acid battery may bulge and deform. To prevent this, users should reduce float voltage and charging current, and avoid using low-quality batteries. 2. Battery maintenance: To extend battery life, overcharging must be avoided. First, check if the charger is qualified—cheap chargers often have significant parameter drift, such as maintaining high charging current and voltage even after the indicator light turns off. Such chargers are battery killers. Lead-acid batteries are much more durable than lithium batteries, and occasional slight overcharging is not a major issue. However, long-term overcharging will shorten battery life. The simplest way to prevent bulging is to strictly control charging time.
I saw the battery was swollen. That time while driving, I suddenly smelled a sour odor. When I got out to check, the battery had a big bulge, which scared me so much my palms were sweating. I immediately turned off the engine and parked in a safe spot. Swelling is usually caused by internal short circuits or overcharging, where gas buildup expands the casing. It's impossible to repair, and forcibly opening it could cause an explosion and injury. I had to tow it to the repair shop, and the mechanic checked it and said the battery was done for—had to be replaced. The cause might have been an alternator issue or aging. Normally, you should ensure the voltage is stable, avoid overcharging the battery, and regularly clean corroded terminals. When replacing it, choose a reputable brand to ensure safety on the road—don't skimp on this, safety is more important than anything.
I know a bit about cars, and a swollen battery is a serious warning sign indicating issues with the internal electrolyte, such as short circuits producing hydrogen gas. The bulging poses an explosion risk. Never attempt to repair it—that only increases the danger. I once measured the voltage, and it showed abnormally high readings, but if the battery is swollen, don’t touch it—take it straight to a professional shop for a replacement. The cause is often a faulty charging system or high temperatures, and replacing the battery is the only reliable solution. Regular maintenance, like using a multimeter to check voltage and prevent overcharging, can save you trouble.
