Just wondering if anyone knows off hand or had a similar experience before I start checking everything in the morning.

So my S5 91 N/A seems to only run off the batt until the car gets up to operating temps. The batt is drained to about 8 volts (depending on how hot it is outside and how long it takes to warm up) then alternator kicks in and power is restored. Also possibly the most important key is that my idiot cluster light are all on until full voltage is restored. Lights are on from start up and only when cold. Any idea's?

Gonna dust off the ol' manual and start checking everything. Hoping someone might have a good place to start. Already checked grounds and cleaned them off. Checked fuses and connections. This has a relay going to the alt right? Also read something about a L wire that excites the alt so I'm going to look for that and check it out. Any advise tips knowledge would be great. Thanks guys.

 

I imagine your alternator is having to self energize its field coils.

New alt time.

 

Yup getting it tested 1st thing. Hopefully its just that, chasing electrical issues is not good times. Thanks.