I've been having issue with my 2001 Maxima.
A few weeks ago, the battery light came on, and all my lights started fading. I was close to home and made it just before my car shutdown. When I looked the alternator bolts had snapped and it was just hanging there. So I fixed the bolting and reattached it.
The car ran fine for a couple weeks. Then one day, my car wouldn't start without a boost. Once I got a boost it ran fine for my 30 min drive, but needed a boost to start again on my way home. So I replaced the battery.
Minutes into my first drive with the new battery, my car completely shutdown. No electrical power at all. I fiddled with the connections to the battery, and my power came back, and the car started.
It worked fine for about a week. Then my car needed a boost again after a 30 min drive. Then on my next drive (after a boost again) the air bag light started flashing, and the lights started dimming, and the clock started flicking off. So I went back home.
This is where I'm at now. What do you think the problem is? Could it be the alternator or battery terminal cables or something else?

Note: The battery light hasn't come on since I fixed the alternator weeks ago.

 

It is something in your battery/alternator/charging circuit. There should be 14.5V on the battery when the car is running and the alternator charging properly. If there is less than 14V, measure the voltage drop on the alternator-battery connection (alternately, measure the voltage on the alternator). In either case, the problem is either the connection between the alternator to the battery, or the alternator itself. The alternator can fail in two ways: a) Not generating sufficient voltage (~ 14V), or b) By discharging the battery when the car is shut off. To test for (b), check the battery drainage current when the car is shut off.

 

1. alternator broke off- you fixed that. Beats me how it could happen to begin with, it's held by several quite thick bolts.

2. battery died- you fixed that but were sloppy on the post contacts: 3. You should've cleaned the posts and wire terminals connecting to the posts and make sure the bolts on the terminals are tight and holding them well on the posts instead of: I'd still clean the posts/terminals for starters. Please note those contacts have to sustain very high current during cranking, about 100A. Such current requires very good electrical contacts to pass through.

 

Definitely clean the battery terminal posts and inside the battery cable clamps. When you re-install the cables on the battery, check that they are tight and cannot be twisted.

Also check where the cable goes into the battery post clamp. If it looks like there is corrosion in there, you will have to get new clamps..

 

https://www.youtube.com/watch?v=FTGz0PKIl84

I hope this may help you out.