Vampire hunting with a digital multimeter

jnj1033

Newly Enlightened
Joined
May 25, 2006
Messages
197
Location
Los Angeles
I picked up a digital multimeter from Harbor Freight for use with my new 18650 setup. Once I got the hang of checking battery voltage, I decided to experiment and find out which of my alkaline lights are "battery vampires."

I put some partly depleted AAA alkaline cells in several of my lights, turned them on, and left them alone for a while. Periodically I switched them off and back on to see how low I could run the voltage before they wouldn't consistently turn on anymore. Once a light started requiring "rest" before switching on again, I measured the cell voltage and moved on to the next light.

I didn't measure runtime- only voltage.

Here are some rough numbers. This is not a scientific test- just some observations.

Dorcy 1AAA LED (brighter version w/ clear lense): Ran a cell down to about .8 volts in this light. Turned it off and back on. Wouldn't light until the cell had rested for a few seconds.

Fenix E1: Required rest to relight around .4 volts. Very dim at this point.

Fenix E01: Down to about .3 volts and still running slightly brighter than the E1 at higher voltage. This test is still pending and will continue tonight.

Lightflux LF2: Not sure where the cutoff is, but definitely won't turn on below 1 volt, even on the lowest (.01 lumen) setting. I assume the microprocessor requires a higher voltage to operate.

Haven't tested my new LD01 yet.

Based on the above observations, the E01 seems like a good light to have during an extended power outage or other emergency. It might not be my initial go-to light, but it will produce usable, albeit dim, light long after my other lights have ceased to function on the same cells. It also works well with depleted cells as a nightstand light, because the dim output doesn't dazzle my night-adapted eyes.

Note: Don't worry- I won't be doing this w/ lithium cells. I'm aware of the safety issues and am not taking any chances.

Sent from my phone. There are many like it, but this one is mine.
 

reppans

Flashlight Enthusiast
Joined
Mar 25, 2007
Messages
4,873
Based on the above observations, the E01 seems like a good light to have during an extended power outage or other emergency. It might not be my initial go-to light, but it will produce usable, albeit dim, light long after my other lights have ceased to function on the same cells. It also works well with depleted cells as a nightstand light, because the dim output doesn't dazzle my night-adapted eyes.

Note: Don't worry- I won't be doing this w/ lithium cells. I'm aware of the safety issues and am not taking any chances.

Consider a moonlight mode light, like a Preon P0, which will also greatly extend batt life when voltage is still above 1.0.

And don't do vampire test with Alks on multi-cell lights either - you'll pop them. Don't ask how I know.
 
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