minershop - Fluorescent Minerals from Greenland and the World

Battery Monitor


This thing is neat no matter what kind of batteries you are using - especially lead-acid. As lead-acid batteries discharge with use the voltage drops linearly. As the voltage drops the lamp dims. Down around 10vdc the lamp will still be lit, but hardly putting out any light. I can't tell you the number of times I've seen people hunting for rocks with a light that was barely lit - the rocks just don't glow very well. But since they were seeing light out of their lamp, they assumed the rocks just weren't glowing. Other packs (like NiMH and LiFE) don't have this linear discharge problem, but it's still a good idea to monitor your battery voltage.

Available from Battery Space ($17) or Hobbico ($10) - links above.

Installation: You can just stick it to the side of your SuperBright or Way Too Cool lamp. As supplied it has a switch to activate it when you want to see the voltage condition. Since it only draws 10ma I think you can do without the integral switch - just bypass it and have it always on when the lamp is on (cut out the switch and splice the wires together). The input wires must be connected to the switched DC inside your lamp (after the on/off switch) - then every time you turn on the lamp, you will also turn on the battery indicator. One of my buddies went so far as to mount the whole thing inside his SuperBright), and just have a slit (cut with a dremel) allowing the LEDS to show thru at the top.


  • Easy, one-button operation. the red, yellow and green LEDs clearly show voltage range from 11.0 to 13.0V. 7-LEDs provide instant, accurate battery voltage status of Low, Safe, or Max. Only one light at a time glows
  • Very lightweight, only 1/10 oz - unit can be mounted anywhere. Draws amazingly low current - less than 10ma
  • Comes with double-sided tape for easy, "anywhere" mounting
  • Perfect for 12V NiMH and 13.2V LiFE battery pack


  • Length: 1.6 in (41 mm)
  • Width: 0.6 in (15.6 mm)
  • Thickness: 0.01 in (3 mm)
  • Weight 0.1 Oz ( 2.9 grams)
  • Power consumption: 10 mA ( 0.01A)


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