Battery or charging ??? on a 1998 Mariner 135

The last time out my engine started & ran fine as usual & tach worked perfectly. I was changing lowerunit oil yesterday & went to trim engine up to get a pan under it & nothing as battery was completely dead. Hooked charger up which showed no connection problems or battery bad readings. I checked & no fuses blown & trimmed it to where I wanted & then left charger on until fully charged which I let charge for about 6 hours. Wonder if a switch accidently left on could have caused this ??? I however didn't see one & honestly just reach under cover & pushed switches to make sure that I now had them off for sure. It had been about a month since charged, but was fully charged as soon as I got home from last trip to lake & I always check them when hooking up & after charging right before unhooking. I've never had a single issue with this battery either. Thanks

Probably the best way to proceed would be to uncover the boat, and INSPECT to ensure that nothing was left on.

A COMPLETELY dead battery is usually an indication that there is a substantial drain.

Yeah Don I know, but I was really suprised when this happened & thought you may have an idea for something to check. I did look around & never saw anything, but I'll check her out again. Thanks http://www.bassboatcentral.com/smileys/thumbsup2.gif

Could be literally any switch or electrical device...

Pay special attention to any BOW mounted switches (which often get WET in the rain, and can short internally). http://www.bassboatcentral.com/smileys/wink.gif

May have accidently left the front graph on. I checked it again today & battery was good to go. Hope that was what it was. Thanks Don http://www.bassboatcentral.com/smileys/thumbsup2.gif