Completely dead Tenergy 18650

[AndyS]

I just experienced a completely dead Tenergy protected 18650. It was recently. charged and working when I installed it in my TK11. The light replaced a crappy one that used to live in my motorcycle saddle bags. It has been in there for maybe a week, but last week was nearly 100 F here, and the bike was parked outside during work hours. The bags are black.

Tonight I tried to turn the light on and got nothing. I measured no battery voltage and thought maybe the light had accidentally turned on and the protection had tripped. I tried charging it briefly but the charger would not even acknowledge its presence.

In the interest of science, I disconnected the PCB and measured the bare cell voltage. It was 0.000 V.

This cell was purchased in Feb '09 from fenixstore.com. It has been recharged fewer than a dozen times. Could the heat have killed it?

Markings:

2600mAH Li-Ion 18650 3.7V
With Protective PCB
Made In China

Anybody else have such an issue? Thanks.

 

[jasonck08]

It seems unlikely that the temperatures you are describing would do that much damage to the cell.... but, it sounds like the CID may have activated, which is why the cell is now reading 0v.

 

[LEDAdd1ct]

What is CID?

 

[45/70]

What is CID?

Circuit Interrupt Device, although we usually refer to them as a PTC, or Protective Thermal Coefficient, which is actually the principle on which the device is based, but anyway, it does sound as if it has activated.

Dave

 

[HKJ]

Circuit Interrupt Device, although we usually refer to them as a PTC, or Protective Thermal Coefficient, which is actually the principle on which the device is based, but anyway, it does sound as if it has activated.

The CID is not the PTC, but another safety device that will break the electric path if the battery has a high internal pressure.
When the CID activates, the battery is permanently disabled.

A PTC is used to limit current and will automatic reset again.

 

[45/70]

The CID is not the PTC, but another safety device that will break the electric path if the battery has a high internal pressure.
When the CID activates, the battery is permanently disabled.

A PTC is used to limit current and will automatic reset again.

Yeah, OK. We've been over this before. At any rate, these devices are located at the positive end of the cell and are unrelated to the protection circuit, or "PCB" which if present, is usually located at the bottom, or negative end of the cell.

Dave

 

[AndyS]

Ok, thanks for the explanation. That makes sense. I've recycled the cell.

 

[45/70]

Andy, in this bulletin from NASA, there is a good cutaway drawing of the positive end of a typical Li-Ion cell. The bulletin pertains to safety concerns when using multiple Li-Ion cells in a "battery" (more than one "cell"), however the drawing presented shows both the PTC and the CID. Both of these safety devices are located under the positive nipple, or more properly "button", in this case. They are actually two different devices, but I tend to think of them as one, even though that really isn't correct.

Dave

 

[AndyS]

Thanks for the link. I also found a bunch more good reading. In mine, it must have been the CID as the cell was cool when I tested it, so the PTC should have been conducting. I don't know why the CID would have tripped, unless the flashlight somehow got turned on. It doesn't seem like the sort of device that could have reliability issues.

 

[45/70]

It's conceivable that the cell got hot enough that the CID activated. If your saddlebags are black, as it seems many are, I'm sure the temperature inside was well above 100F. It's relatively rare, but I think the conditions were favorable in your situation, and that's likely what happened.

Dave

 

[AndyS]

It's conceivable that the cell got hot enough that the CID activated. If your saddlebags are black, as it seems many are, I'm sure the temperature inside was well above 100F. It's relatively rare, but I think the conditions were favorable in your situation, and that's likely what happened.

Dave

Yes, they're gloss black painted fiberglas. I don't think it should have got above the safe storage temperature for 18650, which according to this:

http://www.batteryspace.com/productimages/li-ion/186502400A2 PS.pdf

...should be at least 60°C (140°F) but it's possible. I'll try to remember to toss a thermometer in there tomorrow.

 

[AndyS]

I put a digital thermometer at inside top of the bag, near where I keep the flashlight. It was 118 °F at mid-afternoon, at an outside temperature of 87 °F. Last week when the cell failed it was nearly 100 °F and sunnier, so I could see it could have got to around 130 °F in there, but I bet 140 °F is pushing it. Maybe a fluke. I've ordered an UltraFire 3000 mAH to replace it. I'll report back if it also dies in there. The previous flashlight I kept in there held 3x alkaline AAA and worked every time.

 

[Helmut.G]

I put a digital thermometer at inside top of the bag, near where I keep the flashlight. It was 118 °F at mid-afternoon, at an outside temperature of 87 °F. Last week when the cell failed it was nearly 100 °F and sunnier, so I could see it could have got to around 130 °F in there, but I bet 140 °F is pushing it. Maybe a fluke. I've ordered an UltraFire 3000 mAH to replace it. I'll report back if it also dies in there. The previous flashlight I kept in there held 3x alkaline AAA and worked every time.

hi AndyS,
please read this: http://www.candlepowerforums.com/vb/showthread.php?316888-Fake-Ultrafire-18650-battery-warning
and if you want to, read this too: http://www.candlepowerforums.com/vb...teresting-18650-LiCo-Cell-quot-Shoot-Out-quot

If you want to buy cheap 18650 cells, please don't buy ultrafire 3000 mAh. they are in my opinion one of the worst 18650 cells around. Some trustfire brand cells are regarded "ok" for cheap cells, but it really is best if you develop your own opinion.

 

[AndyS]

Woe, thanks. I wish I could at least say that I only paid $3, but I bought it off Amazon snce I have Amazon Prime and got free 2-days shipping. It arrived today... by I should say _they_ did. Two arrived although I only ordered and paid for one. One of the pair, though, had its shrink wrap half peeled off and dangling. I installed the good one in the light and it's in my bike now.