I have used regular chargers and maintainers on the two Optimas I have had the last 19 years (the first went 13 year, and I have 6 years on it's replacement). I have never had any problems. This story probably comes from the fact that, if an Optima goes all the way down, you can't bring it back with a regular charger. You either have to use a special charger that will put out sufficient voltage when there is little or none in the battery, or you have to interpose a fully charged battery in parallel with the Optima to supply enough voltage to get it going. I have never run an Optima down far enough to have to try this. Although I've never looked, I'm sure their proprietary chargers are relatively expensive.
