Battery Drain and Paranormal Phenomena
It is common knowledge among paranormal investigators that ghosts drain batteries. In reality, it's more likely that I placed a weak battery from a supposed fresh pack. I have witnessed countless times ghost hunters say, "I just put fresh batteries in this." In my experience, don't trust a battery all because you pulled it from a new pack. As part of your investigation preparation, measure the voltage of all your batteries. The voltage of a new battery should be between 1.5 to 1.65 volts. You will be surprised how many weak batteries you will find when you start checking. Also, do not throw away your used batteries. If you suspect that a ghost has drained your batteries, you need to measure their voltage. If documented correctly during an investigation, a set of drained batteries could serve as evidence during your reveal to the client.
Most electric devices will cease to function if the battery voltage drops to around 1.3 volts. If the battery is completely drained, then suspect a ghost. If the battery voltage after use is approximately 1.3 volts, then suspect a high power drain from your electronic device. P.S. A good thing to carry in your ghost hunting kit is a battery tester. You can purchase one from Walmart for under $5.