Remember the 2nd BLF Scratch Build Contest of 2014?
My entry was the Steam Pipe Light built from old brass plumbing parts from a early century paper-mill steam press, and built this light for multiple use capabilities and actual usability. Now it as been 15 months since i placed a pair of then-fresh AA Alkaline batteries in the Glow nightlight part of the light,(which has no off switch) and its still glowing away tonight continuously on my night table beside the bed, after 453 days since the cells began powering it.
I am worried though that these cells may soon begin to leak, and damage the light as i am noticing its definitely a bit dimmer than it started over a year ago.
I can give you the secret & information of the very simple circuit i built for this light to run so long on simple AA cells at your request.
Just a simple low-power, wide-angle (straw-hat type) LED and a 1/8 watt resistor at a value just low enough to allow the LED to “glow” on 3.0 volts. Usually above 15K ohms.
Just a simple low-power, wide-angle (straw-hat type) LED and a 1/8 watt resistor at a value just low enough to allow the LED to “glow” on 3.0 volts. (two AA cells) Usually above 15K ohms. The resistance is so high its almost an open circuit and unmeasurable on my meters. I never thought it would run for a year, and surprisingly its still running on the same cells.
its still running surprisingly.
I don’t know if i may let the batteries run it until it stops glowing, but worried they may leak and damage the glow section of the light, Though once the voltage of each cells drops to 1 volt the LED may go out before the cells get to the point of leaking, as the LED requires a minimum voltage to actually light up.
I looked up your scratch build thread, WOW, very nice work… This is a great follow up to find out that it is still working this long after the fact. I would think the lithium primaries would be worth their cost on how long they would work, but mostly as they would not leak and ruin such a fine light….
I may switch out the 2 AA batteries to Primary Lithium’s L91 cells soon even if the Alkalines are not dead, just to prevent the risk of leakage if & when they do go dead.
