Curt

I’ve been running an Optima 6V battery for two years. Stock regulator, stock generator. Daily use in summer. Zero problems so far. One thing to consider: regulators need to be matched to the generator. The Motors manual lists the correct generator and regulator part numbers for each car. My car is an 8 cylinder 1950 New Yorker and has a 45 amp generator and regulator. They are not the exact original part numbers (per the Motors manual) but are at least matched in amperage. I have no idea what charging amperage the the new regulators sold by the vendors are adjusted for, so I use a vintage NOS Autolite. Also FWIW I have all new original style and gauge wiring. I also tested the regulator per the motors manual and adjusted for the correct voltages where necessary. i have started the car over the winter at 0 F and had plenty of cranking power and duration. Love the Optima so far. Frankly I expected to have problems as you describe, but have had none. The Optima has worked perfectly. I wonder how many cars still have correct original generators and regulators? I’ll bet many have been replaced with anything 6V that would fit.

I went through two regular flooded cell batteries before buying a 6V Optima AGM type for my Chrysler New Yorker with the 323 straight eight. I have had great results using an AGM battery in my airplane the last ten years. Both my plane and my 6V Chrysler sat in unheated storage all winter at -20F temps here is Canada and in spring the batteries crank like crazy and my vehicles fire right up. No charger/maintainer required. I use AGM batteries in all my vehicles now and will buy no other type. They are worth the money.