DateJune 10, 2020
It's been a long time since anyone built a car on any scale that ran on 6-volt power, but there are still plenty of cars out there that use 6-volt batteries and need a 6 volt battery. Unfortunately, since most auto manufacturers stopped producing vehicles with 6-volt electrical systems, they have created dozens and dozens of different 12-volt battery sizes. The end result is that many auto parts stores simply don't have the shelf space to stock a 6-volt battery.
However, OPTIMA still manufactures and sells a 6-volt battery, that you can buy factory-direct & have shipped to your doorstep. Fully-charged, that REDTOP 6-volt battery will measure about 6.3-6.4 volts and keeping it fully-charged will maximize battery performance and lifespan. However, OPTIMA does not currently offer a battery charger that charges 6-volt batteries (see the previously-mentioned lack of demand).
If you are shopping for a 6-volt battery charger to charge 6 volt OPTIMA battery, we'd recommend looking for one that is microprocessor-controlled and has specific settings for AGM batteries (avoid gel or confusing "gel/AGM" charger settings). If you can't find such a charger, most regular 6-volt battery chargers should work just fine at charging an OPTIMA 6-volt REDTOP battery.