Battery Maintained or Battery Storage???
Big Difference: One is where you maintain the battery to be fully charged and ready for service on demand. The other is where you want to extend the battery life as long as possible and you have time to charge it when needed.
I have been following the storage method from an article I read by Battery Council several years ago. The issue with maintaining a battery full charged is the chemical reaction on the plates from not cycling the state of charge. I let my battery discharge to about 12.4v before recharging for 24 hours. If you do not have the discipline to check the battery state of charge, you are better off using a battery tender then allowing the battery to discharge to low which can cause permanent damage.
I can not find the article by Battery Council, but Trojan reference it in there storage procedure. They use less than 12.4v before recharging.
Here is what Trojon has on battery storage:
My current battery is 4.75 years old and is at 98% its rated capacity using a load tester. I only have had to add water twice.