For some reason my battery went dead while the truck was parked. The first time it happened I just figured the battery had finally given up. It was the original battery and it had lasted 8 years. It also sees a huge temperature swing throughout the day in the summer and winter. Plus I don't drive this vehicle much. So I headed down to the parts store and picked up an Optima Yellow Top deep cycle starting battery, slapped it in the truck and went on my way noting that the alternator was charging just like it should be.
Then I parked the truck for a week only to come back and find the battery dead again. I had recently added a camper to this truck along with a couple other wiring modifications. So now I had to backtrack and check all my work. It looked fine. Then I tested the parasitic drain on the battery. Pretty much every vehicle has parasitic battery drain. Newer vehicles with more electronic wingdings generally have more than older more spartan 4x4s. Up to 35 or even 50 milliamps is considered normal for most newer vehicles.
First I made sure everything was turned off. Then I disconnected the battery terminal and wired in my 10-amp multi-meter between the positive battery terminal and the battery cable. I was getting a reading of a little over 1-amp, which is kinda high. However, newer vehicles will spike up like this or higher right when the battery is reconnected. There are computers and other equipment that fires up for a short time when they get power connected. So I waited a few minutes and the meter eventually settled down to 10-milliamps. Perfect. So now that everything checks out, what went wrong, twice? At this point I don't really know. The only thing that I can imagine is that I must have left my backup camera monitor turned on. It doesn't draw much power but over the course of a week it could kill a battery. I'm still not sure if that was it though, so I'll keep an eye on it.