Found Oil on the Engine - Need Advice

[mrlmd1]

This is another example of putting too much faith in something printed, on the internet. On the bottom of that article is a notation 08/99 so I guess that's how old that is. A lot has changed since then and I wonder where that information came from.
Deep cycle batteries can be deeply discharged and survive recharge - they are designed that way. The newer technology AGM and regular lead acid batteries don't like that at all.
If a lead acid battery is in reasonable shape they can be saved by recharging. I can tell you from personal experience with 3 brand new ones, and from researching the manufacturer's web sites for information, even an absolutely brand new AGM battery off the shelf, if put into service without completely charging first, will be shot after the first use and will never hold a full charge again. Those batteries and regular lead acid starting batteries do not tolerate deep discharge very well and do not need to be "excercised" to keep them healthy.
Ni Cads are a different chemistry, they develop a memory and should be fully charged, then totally discharged, then recharged again prior to use. If they are recharged frequently before running down, their capacity will be reduced (their memory). Not so with AGM's or regular lead acid or deep cycle batteries. They all like to be at full charge to function properly. Deep discharge of a regular lead acid or AGM will shorten it's useful life.