Wednesday, September 22, 2010


The LED is still going strong.

Maybe snowbiker will be right with his 5000 hours guess?


  1. snowbiker3:02 AM

    Good thing you don't know who I really am. :) I re-did my math [found an alkaline battery discharge curve] and the little program I wrote [rather than doing the calculus] shows I'm in the ballpark but on the optimistic end.

    One D cell data sheet [Energizer E95] shows they have 20A-hour capacity for light loads. In that case 5000 is about right... at 4800 hours they'd be nearly full brightness but begin a relatively rapid decline. By 5000 hours they'd be one tenth their original brightness and only 1/100th brightness at 5300 hours.

    But if your D cells are have a 12A-hour capacity that I initially read was typical for alkalines, then expect 3000 hours. And if they're 8A-hour "heavy duty" cells then only 2000 hours.

    So I guess what I will learn is whether you by the cheapo batteries or the fancy ones or something in between.

  2. Hi Erik

    I find the whole thing pretty amazing.

    Usually, when I buy batteries like this I give no consideration to their capacities.

    Time will tell...

    This started as a bit of fun for led's I otherwise cannot think of an application for.