What Happens If an Electric Car Charges for Too Long?
2 Answers
Charging an electric car for an extended period is considered overcharging, which can negatively impact battery lifespan. The reasons for this detrimental effect and the charging duration are as follows: Reasons for Battery Lifespan Reduction: Lead-acid batteries inevitably experience water loss during the final charging stage, especially when maintained at high voltage for prolonged periods. This leads to more severe water loss, resulting in excessively high sulfuric acid density in the battery electrolyte. This accelerates plate sulfation and grid corrosion, thereby shortening the battery's lifespan. Overcharging also causes excessive gas to flush the battery plates, leading to active material shedding and ultimately reducing the battery's service life. Charging Duration: Under normal circumstances, an electric vehicle battery typically takes about 4 hours to fully charge. If a four-wheeled electric vehicle is charged for too long, it can cause the battery temperature to rise excessively. While this may not be visibly apparent externally, the battery internals become prone to combustion or explosion. The maximum recommended charging time for an electric vehicle should not exceed 10 hours.
As a user who is somewhat obsessed with EV technology, I often research charging details; the most obvious issue with prolonged charging times is the accelerated battery aging and increased thermal risks. When the battery remains in a charged state for extended periods, internal chemical reactions persist, making it prone to temperature spikes—especially in slow-charging modes, where the likelihood of thermal runaway rises, thereby shortening overall lifespan. Based on my experience, the rapid decline in capacity of many EV batteries is precisely due to frequent overcharging. Worse yet, there are safety hazards, such as reports showing an increase in garage overheating and fire incidents—even with protection systems in place, they can't be fully trusted. I always set the charging limit to 80% and use smart plugs to control charging duration, avoiding a full 100% charge. This helps maintain battery health for over a decade and avoids costly overhauls. At the same time, it affects daily convenience, as electricity bills creep up unnoticed and energy is wasted. I recommend that owners develop the habit of monitoring charging curves.
