I still have the original Japanese 12v in my purchased 2012SL, and it seems to be working just fine. I do check fluid levels (flashlight from rear to see through the case) and I added some distilled water about a year ago just to top off to MAX line. I do use a battery tender occasionally when I’m not going to use the vehicle for awhile both for charge and for desulfation if the latter is really a thing (I don’t pretend to understand it, just that the tender says it does it). At any rate, it will be 7 years old in Feb, 2019.
2012 SL Super Black
12,900 miles, 10 bars showing, 75% SOH, 49.80 Ahr
Model 3 - Basic Black | Long Range | Premium Upgrade Package | Extended AutoPilot | Full Self-Driving
Delivered: July 19, 2018 | 1,200 miles