2005 Intermittent Starting Problem

My wife's 2005 30k Murano Keyless entry is giving me fits. When I turn the switch to start the starter growls like the battery is low. I've checked the battery and it is fine and charged. I did have to put a lot of water in it about 2 weeks ago. About 10 percent of the time it will start just fine.

You know the saying KISS. Well, when I trouble shot this further I found the negative battery post clamp loose. Tightened it up and all of my problems are behind me. Remember KISS! KEEP IT SIMPLE STUPID