Can a battery kill an alternator or can an alternator kill the battery? I had both replaced in February along with an alternator belt.. Now neither is good. The car would sometimes squeal when first starting for the day but go away soon. The other day I drove somewhere and car was fine. When I tried to start, it wouldn't click over at all. Someone came by and he kept turning the key quickly and it started. But again after I went home it wouldn't start. I charged the battery and it will go but after you drive it will not start again. If I charge it with the battery I have no problem starting it several times but once you drive it it will not start. When I had the alternator put in with the new battery my mechanic said the new battery was no good. I took it back to where I purchased the battery and then said it was fine. I took their word for it and 4 months later here I am. Any thoughts?