Did a bunch of work to my truck, put on new 145amp alternator included in the work, so I went for a test drive and it ran great no issues with charging or anything. Parked it and then wouldn’t start the next day, it wouldn’t turn over fast enough to start in -48. So, I went and bought three new batteries(one in the box on my hydraulic deck). Put the new batteries on, put a battery charger on the truck for a few hours. Then went out and started the truck, let it idle for about 15 minutes. And the alternator was not charging at all, it sat in the bottom 1/4 of the gauge running off the batteries charge.
I checked the red box where the alternator hot wire goes. No corrosion. New batteries had good connections. Alternator was working just prior to the new batteries. The alternator literally has two drives on it.
Took the alternator off, opened the back nothing burnt. Nothing broken. Everything connected. I’m going to take it in to get tested tomorrow morning. But is there anything in the mean time I could be missing? I stuck the battery charger back on 4amp charge overnight to make sure the batteries are completely charged up.