Can only one battery be replaced if one out of five car batteries fails?
3 Answers
If one out of five batteries fails, it is possible to replace just that one. However, the grouping requirements for electric vehicle batteries are very strict. The capacity, discharge rate, and static voltage must be almost identical for the batteries to be grouped together. To replace a single battery, the entire battery group must first be removed for a comprehensive inspection. Additionally, finding a battery that matches the original set is quite challenging, and replacing just one may affect the warranty service for the entire battery group. Batteries are typically replaced by the manufacturer as a complete set, meaning the entire group must be replaced together. Each battery group also has a fixed identification code. Precautions for replacing car batteries are as follows: Whether removing or installing, be careful not to let the positive terminal touch any metal. Ensure the replacement is done without cutting power to avoid resetting the vehicle's electronic devices. To do this, first connect the new battery to the vehicle's power supply, then remove the old battery, and finally install the new one. After installation, test all electronic devices in the car to ensure they are functioning properly, such as power windows and audio equipment.
If one out of five car batteries fails, I usually recommend not replacing just that single one, as it may lead to more issues. When car batteries are connected in series or parallel as a group, the entire system requires consistency in performance. New batteries typically perform better than old ones, causing them to bear more load, which increases the burden on the remaining older batteries and may lead to overload failure or shortened lifespan. In practice, I’ve seen many cases where replacing just one battery resulted in the others failing within a month or two, ultimately wasting time and money. The best approach is to check the health of all batteries—using a multimeter to measure voltage or resistance. If one is indeed faulty, replacing the entire set with new batteries is more reliable. Don’t forget to check the battery type; for example, lead-acid batteries are prone to aging-related issues, and regular maintenance can prevent such failures. In the long run, matched replacements ensure more reliable vehicle starts and avoid breakdowns on the road.
My car had a similar issue before. During a road trip, one of the batteries in the battery pack failed, leaving the car unable to start. Trying to save money, I replaced just that single battery. The result? The older batteries couldn't handle the strain and soon started showing frequent low-voltage warnings. That's when I realized the battery pack works as a whole—mixing old and new batteries leads to uneven current distribution, with the new battery bearing more load than the old ones, accelerating wear on the entire system. I learned my lesson: now, in such cases, I first test all the batteries' conditions. If most are still good but one is faulty, I replace the entire set to maintain uniform lifespan. This experience taught me to pay more attention to vehicle maintenance, regularly checking if the battery terminals are clean and the voltage is stable, which can save you from unexpected trouble. Looking back, safety comes first—matching replacements reduces the risk of stalling on the road, making it a worthwhile investment.
