What Causes a Car Battery to Not Hold Charge?
2 Answers
Car battery not holding charge is mainly caused by: severe plate sulfation; significant water loss; single-cell short circuit; excessive impurities in battery cells leading to rapid self-discharge. Battery repair is a highly specialized task requiring knowledge of battery internal structure and working principles. Not all batteries are worth refurbishing - generally, those that can extend lifespan through electrolyte replenishment or charge cycles are worth repairing, while batteries with no voltage or current are not. Below are car battery maintenance tips: Avoid prolonged vehicle parking: Installed car batteries self-discharge during extended parking, so it's best to drive the vehicle at least once weekly for over 20 minutes to allow proper charging. Close windows before turning off engine: Power windows and sunroof operations rely on battery power, so close all windows before engine shutdown rather than after, avoiding using the long-press lock button method. Maintain battery cleanliness: Regular inspection effectively extends battery lifespan. Use professional battery terminal brushes or old toothbrushes to clean positive/negative terminal dust and corrosion. Apply petroleum jelly or grease to contact surfaces to create a protective film.
Last time my car battery wouldn’t hold a charge, it was a real headache—took me a while to figure it out. First, the battery might have been several years old, severely aged, with worn-out internal electrodes. Second, my driving habits were off—always taking short trips under ten minutes, not giving the alternator enough time to recharge, leaving the battery starved. Did I leave anything on while parked? For example, forgetting to unplug the dashcam would silently drain power. Also, extreme temperatures play a role: in summer, the battery dries out easily, while in winter, its performance weakens. Lastly, check the charging system—if the alternator’s output is unstable or a fuse is blown, it won’t charge properly. I regularly test with a voltmeter; a healthy reading is above 12.6V, and anything below 12V is a red flag. For maintenance, I take a weekly 20-minute highway drive to top up the charge and extend the battery’s lifespan.
