potentially dangerous issue with the BLF LT1 concerning the sofirn batteries

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CDylanC
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potentially dangerous issue with the BLF LT1 concerning the sofirn batteries

Recently purchased the LT1 and I love it, but I have noticed that the sofirn 18650 cells have burrs like cheese graters that are shaving material off of the brass positive contact ring in the light. Every time I open it there are brass shaving hanging out in there. If I didn’t clean it out I’m sure eventually the light would short out after manually turning it off and on by turning the battery tube.

This photo was taken after cleaning and then turning the housing half turn increments on and off about 10 times

One could easily remove the burrs from the batteries with some sandpaper but if you never opened the light you would never know and the brass would keep accumulating. I would highly suggest you open your light up and inspect it for brass shavings or burrs on the batteries.

I also assume this could be an issue with the SP36 as it uses the same ring contact design for multiple cells.

For reference I purchased this light on 5/18/2021

jeff51
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Just checked my LTI and one of my SP36.
Neither of them exhibits this issue.
There is some roughness on a couple of the batteries.
But it is below the top edge and isn’t eroding the brass ring.
I’ve had both of these for a while now.
All the Best,
Jeff

Hank33
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Woah that's an eye opener. Hope your tube is okay. Reminds me of roman candles. Big Smile

jon_slider
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> turning it off and on by turning the battery tube.

that looks nasty!
definitely something wrong with those batteries

is there a reason you dont just use the switch?

maybe no one has discovered the battery shaving problem before,
because they dont use the light the way you did, as a twisty?

they just close it once, and done.. no grinding back and forth

WTB Novatac Pocket Clip

CDylanC
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jon_slider wrote:
> turning it off and on by turning the battery tube.

that looks nasty!
definitely something wrong with those batteries

is there a reason you dont just use the switch?

maybe no one has discovered the battery shaving problem before,
because they dont use the light the way you did, as a twisty?

they just close it once, and done.. no grinding back and forth

just looked through the manual and it doesn’t say anything about twisting for mechanical lockout but I have seen it suggested for other lights to stop parasitic draw during storage. I hit the batteries with some 400 grit sandpaper and they seem to have stopped cutting the contact ring.

jon_slider
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CDylan wrote:
just looked through the manual and it doesn’t say anything about twisting for mechanical lockout but I have seen it suggested for other lights to stop parasitic draw during storage. I hit the batteries with some 400 grit sandpaper and they seem to have stopped cutting the contact ring.

glad you were able to fix the batteries
I respect your desire to have the option to lock out the light, without the batteries shaving the contact ring

just for our mutual education…
here are the parasitic specs, from this review :

Aux LED off: 38 uA
Aux LED on Low: 97 uA
Aux LED on High: 1.7 mA

I invite you to check my math, for how long it would take for the parasitic drain to kill the batteries… based on how you use the Aux LED

I think these are the calculations:
4× 3000 mAh batteries = 12,000 mah
if parasitic is 1.7mA, then 12,000/1.7/24= 294 days
if drain is 97uA, then 12,000/.097/24= 5,155 days/365 = 14 years
if drain is 38uA, then … 35 years Grad
I hope somebody will please confirm if I did the math correctly..

WTB Novatac Pocket Clip

Couchmaster
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Thank you for sharing that. Need to start selling them with a fire extinguisher it appears. Not an issue here, thankfully.

GMozz
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I received my LT1 today and also had this issue.

I only opened the light to remove the shipping protector for the batteries (which I now notice has a circular gouge in it), and then screwed the light back together. I then opened it a little while later just to confirm the rev of the driver board, and saw the filings. I cleaned them out, put the light back together and then had to reopen it after testing the Momentary mode, and noticed the filings again, which made me look a bit closer at the problem.

So it does become a problem from just normal use, you can’t just ignore it.

As CDylanC and myself are recent purchasers, it does suggest it could just be a current batch issue.

Henk4U2
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Could it be rough edges around the vent holes act like a grater?
Hard steel (button top) against relatively soft brass can cause havoc.

You are a flashaholic if you are forced to come out of the closet, to make room for more flashlights.

d_t_a
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I’ve had a good number of Sofirn flashlights, but have not experienced that kind of issue (ok.. maybe I might have seen a very few ‘burrs’ a couple of times, but definitely not that much as in your sample. I would report to Sofirn about this issue as it can be serious to have a short-circuit or something to happen..

SammysHP
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Would ne interesting to see which battery is used considering the current li-ion shortage.

rolo2
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Henk4U2 wrote:
Could it be rough edges around the vent holes act like a grater?

That's exactly what's happening here. Got my lamp two weeks ago, including the Sofirn batteries, and decided to have a look after reading this thread today. Not as bad as shown above, but this is definitely an issue, my lamp has been opened maybe 2 or 3 times only. Here are some pictures, first one shows it best:

 

Up close, those vent holes sure look nasty, but nothing some sandpaper can't fix. Those cells cost 2.50 a piece, I guess you get what you pay for Wink

This probably wouldn't even be an issue in single cell flashlights where you don't have the circular movement when screwing on the top.

RichH
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I’ve had the LT1 and Sofirn batteries since it was produced and despite mainly using a 4 bay charger rather than the usb, I don’t have any gouging at all. I do use the switch though and not the lantern body to lock out the light.

Battery production has suffered during Covid, there are a lot of cells that would have been destined for the seconds bin that are being sold.

This is from the blog of my supplier, a reputable seller.

https://www.fogstar.co.uk/blogs/fogstar-blog/why-choose-molicel-18650-ba...

GhostJoe
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rolo2 wrote:

Henk4U2 wrote:
Could it be rough edges around the vent holes act like a grater?

That’s exactly what’s happening here. Got my lamp two weeks ago, including the Sofirn batteries, and decided to have a look after reading this thread today. Not as bad as shown above, but this is definitely an issue, my lamp has been opened maybe 2 or 3 times only. Here are some pictures, first one shows it best:


 

Up close, those vent holes sure look nasty, but nothing some sandpaper can’t fix. Those cells cost 2.50 a piece, I guess you get what you pay for Wink


This probably wouldn’t even be an issue in single cell flashlights where you don’t have the circular movement when screwing on the top.

These cells are DLG 3000mAh 6.4A which are cheap everywhere, only costs $2.5 each from Liion or 18650batterystore (seems price went up to $3 now). I don’t think DLG is one of the 1st tier Chinese battery manufacturers. DLG battery had very bad reputation several years ago not sure whether the quality is improved now.

ShyOne
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rolo2 wrote:

Henk4U2 wrote:
Could it be rough edges around the vent holes act like a grater?

That’s exactly what’s happening here. Got my lamp two weeks ago, including the Sofirn batteries, and decided to have a look after reading this thread today. Not as bad as shown above, but this is definitely an issue, my lamp has been opened maybe 2 or 3 times only. Here are some pictures, first one shows it best:


 





Up close, those vent holes sure look nasty, but nothing some sandpaper can’t fix. Those cells cost 2.50 a piece, I guess you get what you pay for Wink


This probably wouldn’t even be an issue in single cell flashlights where you don’t have the circular movement when screwing on the top.

Great pictures of the problem.
Whoever added the “Button Tops” used a bad batch of them. ✅
But like you said, a little sandpaper or a small file will fix that quickly. ✅✅
djozz
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Looks like it got accidentally hit briefly by the spot welder.

Helios azimuth
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No problem with my March order using Q30 batteries. And the one ordered in 2019 using Sanyo GA flat tops is fine too.
This is a great lantern that gets used often around here. Sorry to hear about your problem and glad you fixed it and posted.

Unloco
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I had the same problem with four SF 26660s (5000mAh 25A) that I bought about two years ago for my L6. When I put the first two on, one scratched the other’s ass. The problem was present in all of them. I solved it by removing the burrs with wet sandpaper.

CR888
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I have those Sofirn 3000mAh 18650 cell which came with LT1, SP36 & others and they don’t have the sharp burred edges on the contact. I agree that a bad batch of terminals is to blame. File/sandpaper will sort it out. Annoying though.

CR888

maxchaos92
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Same issue there with SP36 pro and included batteries,discovered yesterday,and today I found this post,will do a pass with some sandpaper then