My 05 Outback has 115k miles.
I park indoors at home and work. 3 wks ago I stopped outside on my way home when it was raining. It would not start but jumped easily. On the hr drive home the lights on the dash flickered intermittently. The next day I cleaned the terminals with baking soda and water and had no problem for 3 weeks. Until yesterday, when it was raining a lot again and parked outside on the way home, it jumped easily and I drove to a big box store to replace the battery. They tested the old one that was 40 months old and it put out 3v and 0 amps. When I started at the store when they installed the new one (he also cleaned the terminals and batt compartment and applied a corrosion inhibitor) it immediately ran rough - a new condition for me. I drove around the lot and it seemed to surge somewhat and stalled once. I then immediately drove to a mechanic who tested the alternator (original). On the way it stalled twice when I was off the gas near stops. The tech said the first time the alternator showed it was not recharging, but after resetting (the gauge) and retrying it was normal. I believe he checked the belt and alt connections but I didn’t explicitly think to ask, the serprntine belt is less than 1 yr old. When I told him it had stalled he speculated that possibly the idle control was re-learning after the computer was disconnected during the batt change, among other options.
Last note, I have had other (very) intermittent electrical issues the past 3 yrs, including the dash lights all flicker whie driving, the radio volume goes up or down on its own, front left window switch won’t work, and in hot summer driving cruise cont stops during use. I do not want to ruin the new batt and dont want to lose power on the road. The stalling following the batt install doesn’t make sense to me, my dad, batt installer, or the tech.