Original battery just went south after over 5 years and 60K miles. The suddeness of it leads me to believe it had a bad cell. It completely zonked out after leaving the door open for interior cleaning. Replaced with a new Duralast. Last few trips to the track felt like she lost a little bit and the ETs showed it. So my question is...do batteries on their last leg hurt performance at all? I'm kind of hoping the answer is "yes". Thx a bunch.

 

i've never done test on this, but i wouldn't think so since onceyou crank the car the alternator kicks in and all