What failure(s) cause this?

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Cochise334ever
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What failure(s) cause this?

I have Two Ultratac K18 AAA flashlights. They are for my keychain. One is stainless steel and it has an electronic lockout. The other is Alluminun and it doesn’t have that lock out. The lights are about five and a half years old. The one I had been using was a stainless steel version. Put a brand new battery in and went to use the light a few days later and it was dead. I was most certain that the light wasn’t left on because of that lock out. Check voltage and it was 0.528 volts! Put in another battery brand new. Both are 10440 lithium ion batteries. A few days later I went to use the light again. Dead as a doornail! Check voltage and it was identical at 0.528 volts! That proved that it is not the battery. Something wrong with the electronics of the flashlight.

What failure would cause the battery to drain dead within a few days when it’s left in the light. It’s not parasitic drain, something failed inside of it.

I revived both batteries. But I believe I should recycle them. Probably have cell damage. I can’t recall the name of that term / process when they get so low like that then the cells get damaged.They cells degrade by crystallizing?? Something like that. Not worth keeping for only $3 a piece!

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kennybobby
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Copper dendrites grow during excessive discharge; they can be very sharp and puncture the plastic separator film and create an internal short.

Now i used to think that i was cool,
drivin' around on fossil fuel,
until i saw what i was doin',
was drivin' down the road to ruin. --JT

Cochise334ever
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kennybobby wrote:
Copper dendrites grow during excessive discharge; they can be very sharp and puncture the plastic separator film and create an internal short.

Yes…dendrites was the word I was looking for. But that was a Result of the internal mechanisms of the drivers/flashlight failing resulting in batteries being drained extremely quickly and killing them. The batteries were brand new when they went in. So what happened inside the flashlight where it killed the batteries very quickly?That is my question?

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pennzy
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Did you measure the parasitic drain?

wle
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i would suspect the light turning on, and then a protection circuit turned it off at .528V (though that is faulty also, should not go below 1.5V)

you have 2 lights
does the other one do that?

if so i would suspect something common, like accidental turn on, or design flaw

if not, something is wrong with that first light
could be anything really

something shorted

"You never have the wind with you - it's either against you, or you're having a good day."
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It never gets easy, you just go faster.   
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kennybobby
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According to this review it uses a PWM driver to control the 3 modes

https://budgetlightforum.com/node/42939

So that means there is a transistor (likely a FET) on the board. There may be reverse protection also but i haven’t seen the board to tell. It is possible that the FET has a fault and it is draining the cell.

does the light still work using other cells/cell types, etc?

[edit] the 0.528 volts is typical of a diode drop; most FETS have a body diode built in. It could be that is the reason it didn’t go to zero—the diode would quit conducting below the drop voltage.

Now i used to think that i was cool,
drivin' around on fossil fuel,
until i saw what i was doin',
was drivin' down the road to ruin. --JT

Cochise334ever
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pennzy wrote:
Did you measure the parasitic drain?

No.. but it has nothing to do with parasitic drain. I’ve had these lights since February 2016. The batteries have stayed in there months without me having to charge it.

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Cochise334ever
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kennybobby wrote:
According to this review it uses a PWM driver to control the 3 modes

https://budgetlightforum.com/node/42939

So that means there is a transistor (likely a FET) on the board. There may be reverse protection also but i haven’t seen the board to tell. It is possible that the FET has a fault and it is draining the cell.

does the light still work using other cells/cell types, etc?

[edit] the 0.528 volts is typical of a diode drop; most FETS have a body diode built in. It could be that is the reason it didn’t go to zero—the diode would quit conducting below the drop voltage.

After It killed two 10440 Vapcell batteries in a few days. I don’t use the light anymore. I’m using the aluminum one on my chain.

This light can use any Triple-A battery. Lithium primary,10440, alkaline and NiMh…Enloop.

For the heck of it I put those batteries in and it worked but it started to flicker. I’m sure it would kill those after a day or so.

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wle wrote:
i would suspect the light turning on, and then a protection circuit turned it off at .528V (though that is faulty also, should not go below 1.5V)

you have 2 lights
does the other one do that?

if so i would suspect something common, like accidental turn on, or design flaw

if not, something is wrong with that first light
could be anything really

something shorted

The other one works fine. It was absolutely not from accidental turn on. The stainless steel version which is the one that failed, has a mechanical lock out like I said. That was always activated. I use this light for about 5 years. I guess it serves its purpose!

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wle
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maybe water [salt water would be worse] got in it

or you dropped it and something has moved to a different place
for instance an inductor is frequently glued on
if you drop it it may come off and go touch something bad

or a piece of the case is bent and touching something bad now

maybe you have battery corrosion and that is conductive at the power inputs

or a circuit trace has shorted to another one, maybe with greenish copper sulfate
corrosion

wle

"You never have the wind with you - it's either against you, or you're having a good day."
    Daniel Behrman, "The Man Who Loved Bicycles".
It never gets easy, you just go faster.   
-Greg Lemond.
       ,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸

Cochise334ever
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wle wrote:
maybe water [salt water would be worse] got in it

or you dropped it and something has moved to a different place
for instance an inductor is frequently glued on
if you drop it it may come off and go touch something bad

or a piece of the case is bent and touching something bad now

maybe you have battery corrosion and that is conductive at the power inputs

or a circuit trace has shorted to another one, maybe with greenish copper sulfate
corrosion

wle

The batteries are definitely not corroded.. Nothing wrong with the wrapper where it could Short things out.
Who knows! I don’t have the skills to take it apart and test it. All I know is it’s history! I’ve just always been curious and want to know the reasons why.

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Cochise334ever
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The good news is the aluminum version is probably half the weight. Makes a big difference on my keychain!

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wle
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Cochise334ever wrote:
The good news is the aluminum version is probably half the weight. Makes a big difference on my keychain!

copper is over rated
plus it smells bad :P)
wle

"You never have the wind with you - it's either against you, or you're having a good day."
    Daniel Behrman, "The Man Who Loved Bicycles".
It never gets easy, you just go faster.   
-Greg Lemond.
       ,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸

Cochise334ever
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wle wrote:
Cochise334ever wrote:
The good news is the aluminum version is probably half the weight. Makes a big difference on my keychain!

copper is over rated
plus it smells bad :P)
wle

Sir, the failed light is SS not Copper. That’s okay cuz that got me curious and investigated the weights.

These weights are pounds per cubic foot. Aluminum is 168.48, SS is 494.21 and Copper is 559.87 Lbs/ CU.FT.

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wle
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oh
stainless has its minuses too
bad heat conduction
weight
aluminum is cheaper, lighter, gets rid of heat and can be anodized to pretty colors

(i didn;t really know copper is denser than steel}

wle

"You never have the wind with you - it's either against you, or you're having a good day."
    Daniel Behrman, "The Man Who Loved Bicycles".
It never gets easy, you just go faster.   
-Greg Lemond.
       ,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸

Cochise334ever
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I thought stainless steel would have been heavier also. According to that chart I got the info from, my stainless steel version is 2.933 times heavier than my aluminum one.

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wle
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Cochise334ever wrote:
I thought stainless steel would have been heavier also. According to that chart I got the info from, my stainless steel version is 2.933 times heavier than my aluminum one.

without the battery…

"You never have the wind with you - it's either against you, or you're having a good day."
    Daniel Behrman, "The Man Who Loved Bicycles".
It never gets easy, you just go faster.   
-Greg Lemond.
       ,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸

Cochise334ever
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wle wrote:
Cochise334ever wrote:
I thought stainless steel would have been heavier also. According to that chart I got the info from, my stainless steel version is 2.933 times heavier than my aluminum one.

without the battery…

Of course. I’m just comparing the metals. The battery is going to be the same weight. Post image is not functioning. I’m going to get a photo up.

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Cochise334ever
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From L to R.
(Blue) Ultratac K18 Alum., SS Ultratac K18, Olight I3S-CU EOS and Molicel P26A.

For whatever reason the original photo will not post. Once I did a screenshot and attached it it worked. Post image never did that before.

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kennybobby
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If you are interested i would be willing to trace the schematic and figure out what failed, then make the repairs and return it to you.

Aluminum is about 1/3 the density of steel, but the mechanical properties are also low such that an aluminum part has to be 3x thicker to have the same strength and load-carrying ability as steel. The heat capacity of aluminum is great which is why it is used for heatsinks, but it’s coefficient of thermal expansion is about twice as much as steel.

Now i used to think that i was cool,
drivin' around on fossil fuel,
until i saw what i was doin',
was drivin' down the road to ruin. --JT

Cochise334ever
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kennybobby wrote:
If you are interested i would be willing to trace the schematic and figure out what failed, then make the repairs and return it to you.

Aluminum is about 1/3 the density of steel, but the mechanical properties are also low such that an aluminum part has to be 3x thicker to have the same strength and load-carrying ability as steel. The heat capacity of aluminum is great which is why it is used for heatsinks, but it’s coefficient of thermal expansion is about twice as much as steel.

Thanks… that is very kind of you. I have to think about it. The light only cost $20.It would be $8 to $10 to ship it to you and get it back to me. There’s a possibility I might just ship it to you and you could fix it and keep it.

To admit is to acknowledge.To Accept is to take action.