[Shop-talk] troubleshooting LED flashlight again

[Peter J. Thomas]

On 12/25/2013 9:04 AM, John Niolon wrote:
> I tried flipping battery...still dark... checking voltage   one lead on the
> positive battery post and the other on the case where the led screws in... got
> 1.5vdc there... so the problem must be in the led assembly... too small to
> canabalize... it's only about 1/2" in diameter and 1/4" high...  it's just odd
> that all 4 would fail... the seller offered no info except a refund.  BTW
> here's a better link below if anyone is interested...  the others that I
> bought previously are good lites with a long runtime for a single AA.

LEDs have a specific forward voltage and it won't light unless the 
voltage is maintained.  Battery voltage can be different under load.  7 
watts is a lot of power to run on AA and the voltage may drop well below 
the forward voltage with a cheap battery.  Standard "Heavy Duty" 
batteries often supplied with lights do not produce a consistent voltage 
over its life.  The voltage drops over time.  As soon as the voltage 
drops below the forward voltage the LED will not light.  Alkaline 
batteries will produce a more consistent voltage over the usable life 
then drop all at once at the end.  You might try a new, fresh alkaline 
or lithium battery.

>
>
> http://www.amazon.com/BBQbuy-300lm-Flashlight-Torch-Adjustable/dp/B006E0QAFY/
> ref=sr_1_1?ie=UTF8&qid=1347327761&sr=8-1&keywords=cree+flashlighthttp://www.a
> mazon.com/BBQbuy-300lm-Flashlight-Torch-Adjustable/dp/B006E0QAFY/ref=sr_1_1?i
> e=UTF8&qid=1347327761&sr=8-1&keywords=cree+flashlight
>
> and Merry Christmas to all you shop-talk guys... you've saved my bacon a few
> times this year... thanks
>
> john
>
>
> Many people are alive only because it's illegal to shoot them.
>
>
>
>
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