New toys! The Insight keeps its 12v battery at around 12.5-12.8v. I ordered a waterproof battery tender for ~$30 on Amazon to install permanently under the hood, and will run it along with my block heater (on the way) when I remember, before short trips. The tender is only designed to bring batteries to ~80% charge, but it seems it will bring the 12v up to around 13.5v. This should have similar effects to an alternator delete.
Also, next time I do an oil change I'll be installing a fumoto valve, as the oil pans in these cars are notoriously easy to strip.
Inspired by Balto's recent grille block, and now that we're decidedly out of air-conditioning season, I installed my own 50% block:
^ Charging both the big and little battery.
I'm considering moving the air temperature sensor further into the engine bay, or at least behind the radiator, to keep autostop when temperatures are really low.