Solarforce Explosion

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more_vampires

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Just a thought: perhaps discussions of future flash light designs that might better deal with cells venting should go into a thread dedicated to that purpose? Ought not this thread focus on understanding what happened?

You got it, sir.

User provided tests show current draw for that module all over the map, but frequently the rate cited is > 550mA. Here's a discussion on CPF showing a 2010 copy of the module drawing ~600mA driven by 2x CR123A primaries. I have other XP-G modules that draw at 6V ~600mA for ~325 OTF lumen output.

It would appear the SolarForce module in the OP's 2 cell light configuration is likely operating at or just above the apparent "max" current capabilities the cells in question.

Questions:
Did we verify that Subalpine had the 3-12v SF module? Edit: I will proceed with this assumption.
As the cells could not go into cutoff lacking protection circuits, what is the cutoff voltage of this module? Edit: We will assume cutoff of 3v.
Does this actually mesh with use of unprotected cells? Edit: This will draw unprotected cells to 1.5V each, assuming cutoff happened at 3v.

Edit: What's supposed to be the minimum voltage of those 3.0v cells? The maker's website says nothing I can find.
This site claims the 750ma 3v Tenergy cell is protected and minimum voltage is 2.0v
http://www.cr123batteries.com/tener...3-2v-rechargeable-lithium-ion-battery-750mah/

Is link I just posted for a different part number than used in the incident?

We've no idea if these specifications are accurate or not.

We now have an identified issue. Correct and available tech sheets.

Respectfully submitted.
Edit: I hate assumptions in analysis.
 
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chillinn

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Ought not this thread focus on understanding what happened?

How does one stop evolution of a conversation? Gentle nudges (IOW, as you do).

SolarForce likewise do not provide the potential user all the necessary information.

In fairness, but still no excuse, no manufacturer does.
kePKhWr.png

Even with superior unflawed products that properly utilized operate flawlessly, IIRC mentioned earlier, the law is still always caveat emptor.
 

FroggyTaco

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User provided tests show current draw for that module all over the map, but frequently the rate cited is > 550mA. Here's a discussion on CPF showing a 2010 copy of the module drawing ~600mA driven by 2x CR123A primaries. I have other XP-G modules that draw at 6V ~600mA for ~325 OTF lumen output.

It would appear the SolarForce module in the OP's 2 cell light configuration is likely operating at or just above the apparent "max" current capabilities the cells in question.

My understanding of current draw would mean each cell is providing 300mA for a combined total of 600mA @6V.

So they would be well within their stated discharge ability.
 

Beamhead

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It's unfortunate that the only specifications to be found for these cells seem to be located on sales pages of resellers. We've no idea if these specifications are accurate or not. Tenergy appears not to make publicly available a specification sheet for these cells on their own site. If true, that is unconscionable. How can a cell buyer (for flash lights or for any purpose) be assured the cells are fit for purpose otherwise?
Exactly, I have these cells and even the package has little to no data. I purchased them along with the charger from a local big electronics store but I knew going in to only use them in a single cell flashlight which has a low voltage indicator, I have had no issues yet.

I found any data listed on the webpage of the electronics store and another major seller even states in red do not use with xxx brand flashlights.
I find the lack of data/details on the retail packaging and Tenergy's site to be disconcerting.
Also disconcerting is the xxx brand flashlight sells their own Lifepo4 cells and they also have little to no data listed.

I learned from Newbies exhaustive CR123 research that single cell use is much safer but not idiot proof.

As for the OP I doubt we may hear any thing new from him and most can probably figure out why.
 
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more_vampires

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How do we get Tenergy to cough up a data sheet on these cells?

Are they protected or not? One seller was saying they were protected.

If minimum voltage for them is 2.0v and they were unprotected, the dropin would take them to 1.5v, thus overdischarging them.

Is this the culprit?
 
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tandem

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My understanding of current draw would mean each cell is providing 300mA for a combined total of 600mA @6V.

So they would be well within their stated discharge ability.

Only if the cells are connected in parallel. In a 2X light like the SolarForce (or SureFire or Malkoff or most Fenix or ...) they are connected in series.
 
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DenBarrettSAR

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Best wishes to Subalpine for a speedy recovery.. after reading more into it, definitely looks like some sort of battery failure and not a fault of the flashlight. I always been cautious when charging any of my Lithium cells and using them, and a reason why none of my headlights, EDCs, or hat lights use any lithium cells, only NiMH or Alkalines..
 

night.hoodie

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Been following. Solemn wishes for a full recovery, subalpine. Take their emergency medicine, but don't put too much credence in a prognosis of "may never recover;" medical pros err on the side of caution. That is not the tongue with which you were born. Except for retina, various nerves, some brain cells, etc., and unless there is genetic damage due to environmental concerns, you've already replaced your entire body at least 4 times by now. Likely more, as that estimate is merely a safe bet. This is why it is exceedingly rare to permanently lose sense of taste.

Subscribed.
 
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tandem

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When in series, add the voltage. When in parallel add the mAh

Indeed.

Lacking a spec sheet from the maker, we'll have to make some assumptions about suitability for purpose based on the info available "out there".

Tenergy RCR123 LiFePO4 cells:

  • Are not labelled on the cell as to capacity
  • Are advertised by resellers and Tenergy's web site as being 750mAh
  • Deliver runtimes comparing similarly to AW LiFePO4 RCR123 cells rated and sold as 500mAh (also note this discharge chart)
  • Tenergy resellers invariably list the max continuous discharge capability as < 550mAh; combine that bit of information with the observed not claimed capacity this puts the cell in the 1C continuous discharge bracket. As AW 500mAh LiFePO4 cells have been sold for years rated at 2C max continuous discharge (with admittedly short run time), the Tenergy rating may be an implied admission by Tenergy that the cells are of lower quality. Maximum continuous current is a factor of cell quality among other things including size/capacity. Or it may simply mean Tenergy is being conservative, but if they were a conservative company they wouldn't advertise these as 750mAh cells, would they? ;)


Within the host was a SolarForce 3-18V XP-G R5 single mode module:
  • which *likely* draws current > 550mA based on other common XP-G P60 modules running at > 6VDC
  • unfortunately reports from various CPFers show this module all over the map with respect to current draw

Smoking gun? Probably not.

The cells might have not been the best suited for the task but unless the module for some reason was pulling a good deal more than 600-800mA, one wouldn't expect cells of this sort to go poof without warning due to current alone.
 

tandem

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subalpine, why have you today, 2015-01-21 (at least in my time zone), edited your posts from days ago? In particular these two speak to the heart of the matter yet you've revised your answer to a key questions about what cells and what charger without an explanation.

In post #11 you replied to a question about the type of cell used in the light:
tennergy LiFePo4. They were in good condition. More pics to follow, one I am out of the hospitall

Today you altered your reply to:
c123
Last edited by subalpine; Today at 09:05 AM.

In post #29 you had said:
i was using the supplied tenergy charger. it is all still a blur

Today you altered that reply to:
it is all still a blur
Last edited by subalpine; Today at 09:06 AM.

Should we be assuming from your revised answers that you were not running Tenergy LiFePO4 cells in the light? If not, what?

Help us out by clearing this up. We are certainly trying to help you understand what happened, and help the rest of the community in doing so.

Mike


 

LightWalker

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The cells might have not been the best suited for the task but unless the module for some reason was pulling a good deal more than 600-800mA, one wouldn't expect cells of this sort to go poof without warning due to current alone.

What If the batteries were actually mislabeled, unprotected ICR cells?
 

Beamhead

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subalpine, why have you today, 2015-01-21 (at least in my time zone), edited your posts from days ago? In particular these two speak to the heart of the matter yet you've revised your answer to a key questions about what cells and what charger without an explanation.
That is disconcerting, perhaps he was advised to?
 

alpg88

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ForrestChump suggested blow-off panels earlier in the thread, but can't find it to quote.

.

it was not him.

that is what I think too, a small blow off valve like the type some divers lights use, will not be able to handle volume\time of gases, we need to look towards blow off panels,, iirc, lambda from fnf used to build sst90 mag lights, we would drill a hole, in a tailcup, rather large one, something like 1/2 or more, and covered it with a stick on, even thou his lights used nimh cells, he thought of "catastrophic failures" beforehand, even thou chance of nimh exploding is a lot lower.
 

tandem

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Advised to what? Not indicate what cells he used in the light?

That train already left the station when subalpine posted his initial reports here, and invited a TV news crew into his life. The internet doesn't forget. It'll be a little harder to edit out the chunk of nationally-distributed, internationally-available video where he holds up an undamaged Tenergy LiFePO4 cell as an example of what he used in the light.

Call me a simpleton but maybe the simple possibility is the right one? Perhaps subalpine, now that he is recovering :thumbsup: and has had time to look more closely at the incident, has remembered the circumstances a little differently? We've seen that before in at least one incident I can remember off the top of my head. Few people get all the facts perfectly correct soon after suffering a traumatic experience.
 

more_vampires

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it was not him.

Apologies for incorrect attribution.

On topic.

Now about that possibility we were discussing... the REAL on-topic

Possible causes of a kb such as described as mentioned so far: (please add so we can have a better view)
1. Cell charge mismatch
2. Cell protection damage
3. Thermal shock
4. Dropin failure for reasons unknown
5. User error (apologies to all, must be said)
6. Improper integration by the integrator
7. Counterfeit components
8. Improper charging, maintenance, and observation practices
9. Foreign object debris causing undesired performance
10. Undisclosed user modification
11. Other reasons unknown

Don't forget #11, plz.

Are we dismissing cell over-discharge?
 
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