12v Device: La Crosse AA/AAA Charger
La Crosse BC-700CBP AA/AAA Charger This charger is awesome because it has an automated battery refresh function that can bring a completely useless NiCd or NiMH back to full working service. This charger can charge or refresh 4 cells at a time, can measure capacity, and generally works great. Now, the down side.. It requires a 3v DC power source, so in order to run this from 12v, you must use a DC/DC buck converter. I made one for this charger and it works great from 12v.
12v Device: Sanyo USB AA/AAA charger
Portable Sanyo NC-MDU01 USB AA/AAA charger This little charger is about as basic as they come while still being a smart charger. It came in a bundle deal with 2 batteries and I picked it up around 2010. Still works great and I keep it in my backpack at all times for charging in a pinch. Only downside.. Can’t charge AA and AAA at the same time, can only do one or three other type of battery. Thankfully, I’ve never needed to do that, so no complaints here.