Utorch UT02, parasitic battery drain?

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james y
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Utorch UT02, parasitic battery drain?

This morning I picked up my UT02 and it doesn’t light. I took out my LiitoKala blue from the flashlight and using a multimeter discovered that the voltage of the battery is zero. I have left the flashlight alone for about a month plus.

My refresh charger can’t charge this battery so I guess this cell is not protected. Nothing wrong with the flashlight once I put in a fresh LiitoKala.

The 2nd question is, should I bin the zero volt battery?

The specs for the UT02 Working Voltage is 2.8-4.35V, so I guess there is no cut off voltage?

Edited by: james y on 04/10/2017 - 23:36
Lexel
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Lithium battery gets internal damage from over discharge
you may get it charged again, but the risk that the cell gets an internal short is dramatically increased

There are similar sized mobile batteries go firework seriously burn their owners

If you dont want a small tube bomb in your house or hand put it to recycling
as its completely discharged use a hammer or other tool to physically destroy the cell so nobody tryes to revive it

when the light is loaded with a new cell use a 1kOhms resistor between battery and tube and read mV on a DMM
each mV is 1uA parasitic drain
usually e-switch drivers have 15-50uA standby drain

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Lightbringer
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Side-switch? Yeh, pretty sure it’s “always on”.

I always TCLO my DV-S9 by giving the tailcap ¼-turn or so, to break contact. Otherwise it’s a 10mA parasitic drain.

0V sounds like a protected cell that started protecting. Possible to jolt it alive again, but others would frown on that idea and suggest just tossing it.

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Lexel
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Lightbringer wrote:
Side-switch? Yeh, pretty sure it’s “always on”.

I always TCLO my DV-S9 by giving the tailcap ¼-turn or so, to break contact. Otherwise it’s a 10mA parasitic drain.

0V sounds like a protected cell that started protecting. Possible to jolt it alive again, but others would frown on that idea and suggest just tossing it.

Littokala does not produce protected cells

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Lightbringer
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Lexel wrote:
Littokala does not produce protected cells

Then 0V is really dead…

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giorgoskok
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I got 2 liitokalas from banggood back in December that after 1 month of use they died , turning to 0 volts …

Since then i have been using other liitokalas in these flashlights without issues .

james y
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Lightbringer wrote:
Side-switch? Yeh, pretty sure it’s “always on”.

I always TCLO my DV-S9 by giving the tailcap ¼-turn or so, to break contact. Otherwise it’s a 10mA parasitic drain.

I also have the DQG Tiny 26650 which I believe might work in the same way, ie, always on. The cell from this flashlight reads 3.8V when I took it out to check.
I think we need to be aware , especially if we use these type of flashlights on our car. The battery might be completely drained the next time we switched it on.

Lightbringer
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james y wrote:
I think we need to be aware , especially if we use these type of flashlights on our car. The battery might be completely drained the next time we switched it on.

I never leave any Li cells in my car. They’re never happy in temperature extremes.

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maukka
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8.4 µA on my UT02.