Hello! Are these facts about my electrical system enough to pinpoint the problem on my 99 Nissan Altima?
FACTS: In early April, the following were replaced: alternator/serpentine belt, a few pulleys, and compressor belt. In mid-May, I started using the A/C, and got a very short squeal from the belt each time. On May 21, the approx. 4.5-year old battery died. Next day, Advance Auto tested the battery, confirmed it was finished, so I got a new battery. June 8, while driving home, the radio turned on and off and so did the lighter (cell phone was charging) several times. As I pulled up at home, some dash lights flickered. Turned the car off, but it would not restart. Connections and cables were good.
Spoke by phone with my pro-mechanic and friend-mechanic; both insisted the alternator was fine, and battery was defective. Next day, jump started the car, Advance tested the battery serveral times, the read-out finally said the battery was bad, needed to be replaced, and alternator showed excessive ripple (764mV). They replaced the battery. Two days ago, my mechanic friend sprayed belt conditioner on both belts (alternator and compressor), then the squealing from A/C stopped. Yesterday, I had the alternator re-checked, still excessive ripple, but smaller than before (now 312mV).
QUESTIONS: Is the alternator the source of the problem here and thus needs to be replaced, or could the loose belt (compressor, I assume) or something else be causing the excessive ripple problem with the alternator? I just don't want to replace the alternator and then still have electrical problems afterward because I missed the real problem.
And by the way, can a bad alternator damage the battery? I am wondering if the alternator has been bad for the past few months and is responsible for killing both the 4.5-year old battery and the new one that lasted three weeks.
Thank you for any attention you can give to this post! Please let me know if you need any more information.