Run them till they die...

Are there any negative side effects to running high output led's at lower power?

If I continue to use my 6PL after it has obviously become what they term "useful light" am I doing any damage?

Limey Johnson said:

Are there any negative side effects to running high output led's at lower power?

If I continue to use my 6PL after it has obviously become what they term "useful light" am I doing any damage?

Click to expand...

The LED and circuitry doesn't care, but doing so will hurt rechargeable batteries.

LEDs dim by themselves(after thousands of hours). As long as they(LED + driver) don't overheat, they should be fine.

Genearlly the negatvie side effect is on the ego of the owner if someone catching his light on low batteries..

Crenshaw

It's good nobody wanted to use my L1 this morning. I fell asleep with it on low last night and it was dead when I awoke. Actually it was nearly gone anyway so I had parked it at bedside as a nightlight.

Geoff

Compared to incans, LEDs are more efficient at lower power. It is actually harmful to incan filaments, but LEDs are fine with it.

schiesz

I'm running a Tiablo A9 Q5-wc from a battery pack consisting of 6 eneloop's in series (7.2v), between this is a PWM dimmer providing 5% to 100% viarable dimming. I'm getting about 5 hours run time, combined with maximum brightness whenever needed (unlike an 18650). This setup is working well.

cheers.

"Based on internal long-term reliability testing and standardized forecasting methods, Cree projects XLamp LEDs to maintain an average of 70% lumen maintenance after 50,000 hours, provided the LED junction temperature is main[FONT=Verdana,Verdana]tained at or below 80°C.[/FONT]" - cree.com

So nearly 6 years(non-stop!) use to reach 70% output & presumably running LEDS at say 75% of their maximum output increases the lumen maintenance period accordingly? Or does it?

Owen

Limey Johnson said:

Are there any negative side effects to running high output led's at lower power?

Click to expand...

Yes, you can't see as well.

Hitthespot said:

Yes, you can't see as well.

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On a similar vein "Yes, you get mugged!"

Thanks guys. The first time it happened, I tossed the batteries and put in fresh.

I use the Surefire 123's and have the spare battery case. This time, I'll use them until they are completely dead.

I have my light just because it's a light...no specific use. For getting around the house I can use nearly dead batteries...If I venture outside I can easily throw in a fresh set.

Thanks again for setting me at ease...for $91, I didn't want to do any unneeded damage to my light.

I believe 6P uses 2 CR12A batteries.
There are precautions needed to avoid an exploding battery if you want to run them into the ground.
Please read this:
Exploding 123A Batteries?
http://flashlightreviews.com/features/123burst.htm

LEDninja said:

I believe 6P uses 2 CR12A batteries.
There are precautions needed to avoid an exploding battery if you want to run them into the ground.

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While I agree that anyone using CR123A cells should be familiar with these precautions, I do not see how this is related to 'running cells into the ground'.

Do not, for instance, take a cell that you have 'run down' and match it with new cell in your light, but I don't think anyone here has suggested that.

There is no increased danger, that I have ever heard of, from running CR123A cells all the way down.

schiesz

The original poster is new to CPF and may not be aware of the extra precautions needed with lithium cells.

Most of us buy lithium powered lights for their brightness and will change the batteries as soon as the torch starts to dim. However the following sentence indicates the OP wanted to maximize battery life. He needs instruction on how to do that safely.

Limey Johnson said:

If I continue to use my 6PL after it has obviously become what they term "useful light" am I doing any damage?

Click to expand...

There are 2 threads on exploding batteries in the last 3 months. In the 1st case after the torch started to dim the member continued to run the light to see how long the batteries would last. In the 2nd case the torch had started to flicker 2 days before the explosion. Both of these explosions could be avoided if the batteries were swapped out at the right time. While in both these cases the batteries are AA lithiums of unknown quality, Surefire batteries have their share of explosions.

Rapid Vent of Nuon AA aka Minimag Firecracker
https://www.candlepowerforums.com/threads/189424
Exploding Batteries
http://candlepowerforums.com/vb/showthread.php?t=170080

FWIW, I looked through the linked thread and found nothing to indicate that using all available energy in a CR123A battery (or lithium AA battery for that matter) increases the chance of exlosion, venting or other danger. I'm not doubting that its there, but I couldn't find it.

I am not trying to say that there is not some precaution that needs to be used with lithium cells, but I have still not seen anything that indicates that using the batteries past the point of dimming is dangerous.

The obvious exception here is using unprotected lithium ion batteries. When they dim in a light, you should remove and recharge because they could be dangerous to RECHARGE if they have depleted past a certain level.

Can you link the examples, or explain why extended use causes increased danger? Is it the heat created from extended use, and not the level of remaining capacity in the battery?

schiesz

Sometimes battery in series will discharge unequally, one will be dead while other one isn't (don't ask me why). This seem to be true not only for lithium but alkaline as well in my experience.

schiesz said:

Compared to incans, LEDs are more efficient at lower power. It is actually harmful to incan filaments, but LEDs are fine with it.

schiesz

Click to expand...

Only if incans are running at lower than their designed power. I'm sure that's what you meant to say. 'Harmful' is also relative depending on the bulb design.

ampdude said:

Only if incans are running at lower than their designed power. I'm sure that's what you meant to say. 'Harmful' is also relative depending on the bulb design.

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Exactly. I guess I should have said "It is actually harmful to incan filaments to run at lower than their designated power"

With the turns the thread has taken, it sounds like it is safe to say that, while it is NOT harmful to the LED to run at lower than their designated power, it might be harmful to YOU when it causes the lithium primary cells to vent with flame.

'Harmful' is quite relative in this case as well.

schiesz

In any case...heres my earlier thread on lights that suck batteries dry, as well as links to exploding battery threads.

https://www.candlepowerforums.com/threads/185691

Crenshaw

great reading...and thanks.

here's another thing thing I'll throw out there.

Please don't ask me why, but since forever, in ANY light, lithium or not, I occasionally reverse the batteries.

This meaning I take the front cell and switch it with the back cell.

After reading these dangers, I wonder if it's just not best to run the light, till it dims, and grab a new set. I always have 3 sets on hand.