My battery keeps dying even after replacement, what could be wrong?
Quote from TechDIYTony on June 16, 2025, 11:07 amHey guys,
I’m really frustrated. I replaced my car battery last month because it kept dying overnight. Now the new battery is doing the same thing — completely drained if the car sits for a day or two. I double-checked the installation; terminals are clean and tight. The alternator seems to be charging fine while driving (around 14.2V).What else could be causing this constant battery drain?
Any help or ideas are greatly appreciated!
Hey guys,
I’m really frustrated. I replaced my car battery last month because it kept dying overnight. Now the new battery is doing the same thing — completely drained if the car sits for a day or two. I double-checked the installation; terminals are clean and tight. The alternator seems to be charging fine while driving (around 14.2V).
What else could be causing this constant battery drain?
Any help or ideas are greatly appreciated!
Quote from DIYDan on June 16, 2025, 11:16 amIt could be an ongoing parasitic draw. Check interior lights, glove box light, trunk light, or even faulty modules. Sometimes shorted diodes inside the alternator cause overnight drain too.
It could be an ongoing parasitic draw. Check interior lights, glove box light, trunk light, or even faulty modules. Sometimes shorted diodes inside the alternator cause overnight drain too.
Quote from CarGuyBrad on June 16, 2025, 4:34 pmIf the battery keeps dying even after replacement, it could be a parasitic drain — something is drawing power while the car is off. You may want to do a parasitic draw test using a multimeter. Also, check your alternator’s charging voltage; it should be around 13.8V–14.2V when running.
If the battery keeps dying even after replacement, it could be a parasitic drain — something is drawing power while the car is off. You may want to do a parasitic draw test using a multimeter. Also, check your alternator’s charging voltage; it should be around 13.8V–14.2V when running.
Quote from LadyGreaseHands on June 17, 2025, 3:02 pmYour freshly replaced battery keeps dying because something in your car is continually draining it — this is called a parasitic draw. Common culprits include glove-box/trunk lights, aftermarket accessories (like a plugged-in OBD-II dongle), malfunctioning modules, or even the alternator/charging system not working correctly
Your freshly replaced battery keeps dying because something in your car is continually draining it — this is called a parasitic draw. Common culprits include glove-box/trunk lights, aftermarket accessories (like a plugged-in OBD-II dongle), malfunctioning modules, or even the alternator/charging system not working correctly
Quote from CheckEngineChamp on June 18, 2025, 10:50 amEven with a new battery, issues like a faulty alternator, parasitic drain, or loose battery connections can cause the battery to keep dying. It's best to check the charging system and look for any electrical drains.
Even with a new battery, issues like a faulty alternator, parasitic drain, or loose battery connections can cause the battery to keep dying. It's best to check the charging system and look for any electrical drains.