I have a 2009 Subaru Outback 2.5 4AT with 181,000mi. When the temperature dips below 20 degrees F, the alternator will not charge for up to 15min after starting. I have replaced the battery and the alternator (OEM). This did not correct the problem. This does not occur when it is warm outside. (Warm in Wisconsin is anything over 25 degrees and cold is less than zero)
Sounds like a parasitic drain somewhere in your charging system.....
I checked, none found
There likely is no problem at all. It's engineered that way.
"Extreme cold and high heat reduce charge acceptance, so the battery must be brought to a moderate temperature before charging."
https://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures
Why would it only start at 181,000mi?
oh. well something must have changed then. Some temperature sensor?