To answer your question, if an Optima becomes discharged enough, a regular charger may not see enough load to start charging the battery. In such a case, connecting a fully charged 6 volt battery in parallel with the Optima and then connecting the charger will start the charging cycle. In my case, I have a variable DC power supply that I use to charge mine; I just increase the voltage until the Optima starts to charge. New chargers are too "smart" to do that.
Also, be aware that an Optima is not a "dry cell". It is still a lead acid battery, but is built on a different principle called "AGM" (Absorbed Glass Mat).
I am away from my cars for 6 months in the winter. During that time, I use a regular battery maintainer on my Optimas and have never had a problem getting the cars started when I return.
If anyone is interested, here's another trick I use. About 6 years ago, I had a maintainer go bad, and it boiled one of my batteries (not an Optima). From that time on, I have had the maintainers connected through a cheap timer (available for less than 10 bucks). After some experimentation, I found that setting it to turn the maintainers on for 15 minutes a day is enough to keep the batteries up, and I don't have to worry about none going bad again.
From my experience over the last 5 years, there is no problem with parasitic drain. Every year I come back to 7 fully charged batteries. When the one maintainer went bad 6 years ago, I contacted the manufacturer (Schumaker). They said that this is typically the way they fail. (BTW, they sent me a new maintainer, gratis).tubman's idea got me wondering though....Does a battery charger/maintainer connected to a battery in a powered off state act as a 'load' on the battery? That is, would the charger/maintainer act like a parasitic drain on the battery???....
I'm with John all the way , same story with my 6v optima for the last 8 years !I don't put my Optima batteries on any type of trickle/maintainer charger even during the time my car sits dorment during the winter, which is about 3 months here in MD. Unless you leave your system energized (no battery disconnect switch), and possibly have some type of drain on the battery, it is not necessary to keep them on any type of battery maintaining system for that period of time. I put my avatar car away on Thanksgiving day '15 and didn't touch it until the first week of March '16. There was no real problem starting my 35 fordor sedan whatsoever. Cranked the engine like I had a 12V battery.
tubman's idea got me wondering though....Does a battery charger/maintainer connected to a battery in a powered off state act as a 'load' on the battery? That is, would the charger/maintainer act like a parasitic drain on the battery???....
The rectifier/diodes in it should keep it from draining the battery.
I think I would have noticed that!I'm thinking the thing to do is to put a Ohmmeter across the leads of the charger when unplugged to see if there is a high resistance short....