Why does the new battery lose power when accelerating?
2 Answers
Here are the reasons why a new battery loses power when accelerating: 1. High starting current: The current is about three times that of normal driving. The combined resistance of the wiring, internal resistance of the battery, and the controller's field-effect transistors, along with high-current discharge, causes significant voltage fluctuations. 2. Charging duration: Battery self-discharge. Some users don't ride their electric vehicles immediately after fully charging them, leaving the battery unused for several days without timely recharging. 3. Damp wiring: If the electric vehicle is frequently used in rainy or snowy weather, damp wiring could also be a possible cause.
I also encountered this issue after replacing the battery. The voltmeter drops when accelerating, especially with the AC on. Actually, the most common culprit is the alternator—don’t blame the new battery. At higher engine speeds, the alternator should generate more power, but if the carbon brushes are worn or the voltage regulator is faulty, it simply won’t charge. Also, check the battery terminals—if newly installed connections aren’t tightened properly, high current can cause sparking and overheating. Cars with aftermarket audio or LED lights need extra attention, as power-hungry accessories can overwhelm the charging system. Another small but critical detail: a worn or slipping alternator belt won’t transfer power efficiently even at high RPMs. These require professional diagnostic tools—DIY attempts often lead to misdiagnosis.
