FlightISIII

i recently had an issue with my battery and alternator. my car wouldnt start, the dash lights were very dim and if I switch my headlights on, drain. so i jumped my car, juice back up and got the motor running. i let it idle for 3-6 minutes, then would completely shut down and it wont re-start. jumped again, starts then would simply die. from my understanding, the alternator once charged should hold the charge, it doesnt need the battery assistance, so we assume i have a bad alternator (200k on original alt) i replace my OG alt with a new one, low on charge so we jump start. works fine, idled for 10 mins or so then shuts down. wont restart. jump again, revving the engine, holds, then shuts down again. i buy a brand new battery, my old one was dead, install the new one and now the car works like a charm, didnt even need a jump. i take the OG alt back for a check and it passed, low on voltage but passed. does anyone know for sure if the alternator NEEDS the battery consistantly to hold its charge? will the alternator fail it its running everything, heats and will shut down the car? im just wondering if maybe theres something im missing and might happen again, the car is running fine but dont want to risk of shutting down on the road.

dsp979

You have it backwards. The alternator provides the charge to the battery.

Your battery was completely dead. In other words, it wouldn't hold the charge, even with the new alternator.

Should have bought the battery first, saved yourself the $$ on the alternator.