Battery Randomly Dying - Would This Help Troubleshoot It?

[LuvNLife]

Went out to start my truck and run some errands, and the battery made 1 revolution of the engine, then quit. Waited a few, and it just clicked. The battery is an Interstate, 850 CCA, and less than 1 year old, and this isn't the first time it's happened. I've had the battery checked with a load tester (passed) and it's putting out 14.4 when running. The in-dash gauge shows charging for about 3 minutes after I start it, then settles back to 13+. All of my hot and ground wiring and connectors are good, clean and secure. My battery charger is charging right now, but it'll fire up as soon as I connect it. The truck had been sitting for 4 days. The last time it happened, I stumbled across the face plate of the radio being installed as the possible culprit; with it removed, this hadn't happened for quite a while. Other than the radio, the only non-stock items are a cheap tach (installed after the initial problems) and a Summit fuel gauge (installed the same time the problem started) It seems something is creating a drain or feedback.

Trying to troubleshoot electrical issues is a nightmare for me. I was hit with 45Kv setting the timing on my Nova 40 years ago (hot summer day, sweating, no shirt, laying across fender) and have had a healthy respect (fear) of electrical ever since. To begin narrowing it down, I was looking at something like this:

http://www.mamotorworks.com/Corvette...uitry-100517-1

My thinking is, it's an inexpensive, quick and dirty anti-theft, and, if the battery still went down after a week or so of sitting, that would prove there's some accessory grounding, feeding back, etc., since the only power going to the vehicle is through the fused bypass wire.

I sure could use some thoughts and opinions on this one.

Jerry