Flashlight BURNED! What did I do wrong? (Seraph SP-9, D26/TL-3, 2xIMR18500)

hoongern

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Hi guys,

I'm not sure if this should be in the general forum, battery forum, or incan forum.

So JUST 2 hours ago I opened up my package with brand new AW IMR18500 Lithium Ion batteries, and couldn't resist doing beamshots. So I was out doing beamshots, and I decided to change from the LF IMR-9 module over to the FM D26 T1.5 socket. I left the batteries inside while changing it.

When I tried to turn on the light (Using the twisty switch) - I noticed the light flickered and died. At first I thought it was just the contact, or at worst, the bulb going :poof:. Then a second or so later, I realized that the body of the flashlight got pretty hot. So I opened it up.... Sighhhhhhhhhhh...

There goes a huge amount of $$ down the drain in a couple seconds.

battery.jpg


tailcap.jpg


d26-module.jpg


Now my question is -

What did I do wrong? Are you supposed to remove batteries when changing D26 modules? All parts were working fine, so it's definitely not FiveMega's, LumensFactory's, or AW's fault. But I just did what I'm used to, just swap in a different module. And I didn't notice any problems until I tried to power it up. Of course, there must have been some short circuit somewhere.

I'm gonna have to write off these BRAND NEW batteries, sigh, get a new tailcap, get a new D26 module, unless I can acquire just the springs.

Also, it didn't smell good. Should I be worried about any chemicals?

Regardless, let this serve as a warning to all about the awesome power of IMR cells, and high powered incans. Definitely not the nicest thing to experience. Thank God IMR cells are safe chemistries.
 
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jwyj

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Happened to me before. I don't think you need to write off the tailcap and the D26 module. Just use tissue paper and clean them up. They will be as good as new. Also give the inside of the flashlight body a good wipe.
 

LED_Thrift

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Thanks for sharing, and I'm glad YOU are OK. Sorry about your burned equipment. I can't really offer a good guess as to how that short happened, so I won't speculate.
 

hoongern

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I guess I will always be removing batteries now before making any module changes. My only guess as to how it could have happened is that the spring must have bridged the gap between the positive terminal and the body of the flashlight for a split second, all which was needed. In hindsight, I should have been more careful and realized that this could have happened.

Lesson - always take care - you can never be too careful.

As for the module & tailcap, I think they're mostly ok. They just need a spring change. Shame about the IMR cells though - brand new!
 

DM51

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My only guess as to how it could have happened is that the spring must have bridged the gap between the positive terminal and the body of the flashlight for a split second
Ouch! I think your guess is probably correct - the tail of the spring was probably off-center and gouged away the plastic insulation, causing a short.

Due to this being an IMR cell and the very substantial currents possible with these cells, I'm going to move this thread to the "Smoke & Fire" dept of the Batteries section, as SilverFox may want to comment on this.
 

hoongern

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Ouch! I think your guess is probably correct - the tail of the spring was probably off-center and gouged away the plastic insulation, causing a short.

Due to this being an IMR cell and the very substantial currents possible with these cells, I'm going to move this thread to the "Smoke & Fire" dept of the Batteries section, as SilverFox may want to comment on this.

Sure thing. I just hope that people realize that they should probably be taking out batteries when changing modules! Definitely not a nice experience!

Now, another question - how does one dispose of brand new but destroyed batteries? They're still fully charged...
 

kramer5150

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I have had cases with unusually tall B+ springs that "fold" over and become dislodged to the side when compressed. Many times its because I do not solder the spring flat, so even the slightest "lean" and it pops off the B+ terminal.

I have also found its a good general practice to completely remove power when working on these things. So yes its worth your effort to remove the cell(s) before module swapping.

Thank goodness you weren't hurt.

Spent cell recycle procedures vary greatly from country to country. I would start with a google search "malaysia battery recycle locations".

On a bit of a side note... one of the design parameters for mechanical coil springs is the amount of compression the spring can sustain (from at-rest), before it becomes unstable and starts to go "boing", and but-out sideways. They are only designed for physical stable operation within a certain range of compression. Obviously the amount of stable compression can vary greatly from spring design to design.
 
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Black Rose

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Wow, glad you are OK.

I usually leave cells (protected LiCo) in my bodies when I swap D26 modules, making sure that the twist/clicky switch is off.

I think I will start taking the cells out when I swap drop-ins, especially now that I have some LF SR-9 drop-ins on the way, with some IMR cells to follow.
 

Cuso

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Leaving the batteries in while working with a module is lazy and bad practice, given that the spring may come in contact with both polarities while the modules settles in. ALWAYS REMOVE YOUR BATTERIES BEFORE PLAYING LEGO. But I do wonder if the light was "on" at the tailcap? Should the body not be negative unless the tailcap is pressed/twisted in?
 

Linger

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That's a long spring on the FM module (atleast before its deformed as in OP's picture). Presumably there was a reason why it was choosen, I will say it requires extra care to use it properly. Always start with an empty tube when loading the FM module, after bezel is screwed on tight, flip the light over and check up the body and see the center spring is centered. If you're using a 2nd -'ve spring (not included in OP's pictures) its especially important to verify the springs are dead center (and thus well clear of each-other).
Then load in the cells, apply tailcap.
 
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SilverFox

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Hello Hoongern,

It looks like the + end of the cell has a bunch of gunk deposited on it, with a little melted spot where the short occurred.

If it were my cell, I would clean it up and apply some anti corrosion liquid (I use Corrosion Block) to the + nipple. I would then apply a drop of nail polish to the area of the shrink wrap that melted, and see how bad the cell really is.

Set your charger on a heat resistant surface outside and see if the cell will charge. At the end of the charge let the cell sit for 30 minutes, then measure its open circuit voltage.

I have actually seen cells in much worse shape still have 95% of their initial capacity and go on to be used for a long time.

On the other hand, it is possible that the cell is damaged and should be recycled.

I am often amazed as to how much these cells can take. Li-Ion cells perform very well under very large loads, as long as the duration is very short. Since the shrink wrap on the cell is not damaged, it doesn't look like the cell heated up enough to damage the cell.

The biggest problem in future use will be corrosion of the + nipple. The heat may have melted off the plating, and this will add resistance to any circuit you use the cell in.

Looking further into this, if this cell is still working well, AW may give you trade in value on it when you get a replacement for it. He may not have a data point from a shorted cell. No guarantee's, but it may be worth getting in touch with him about it.

Be safe and take care.

Tom
 

hoongern

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I doubt that the battery that sent that much current out [in a very short time] is still fully charged.

The resting voltage of both cells are over 4V, 4.06v in both cells actually, which is still a considerable charge.

Wow, glad you are OK.

I usually leave cells (protected LiCo) in my bodies when I swap D26 modules, making sure that the twist/clicky switch is off.

I think I will start taking the cells out when I swap drop-ins, especially now that I have some LF SR-9 drop-ins on the way, with some IMR cells to follow.

I'm glad that I'm ok as well! Yeah, I now think it's good to take out cells when changing modules esp if they have long springs.

Leaving the batteries in while working with a module is lazy and bad practice, given that the spring may come in contact with both polarities while the modules settles in. ALWAYS REMOVE YOUR BATTERIES BEFORE PLAYING LEGO. But I do wonder if the light was "on" at the tailcap? Should the body not be negative unless the tailcap is pressed/twisted in?

I think that this warning should be made clearer to people as i don't recall this warning when going through all the safety stuff. The light was definitely in the off position, otherwise I would not have been changing modules! The trouble started when i turned it on. Spring wasn't centered, i believe, as mentioned below by linger.

That's a long spring on the FM module (atleast before its deformed as in OP's picture). Presumably there was a reason why it was choosen, I will say it requires extra care to use it properly. Always start with an empty tube when loading the FM module, after bezel is screwed on tight, flip the light over and check up the body and see the center spring is centered. If you're using a 2nd -'ve spring (not included in OP's pictures) its especially important to verify the springs are dead center (and thus well clear of each-other).
Then load in the cells, apply tailcap.

Hello Hoongern,

It looks like the + end of the cell has a bunch of gunk deposited on it, with a little melted spot where the short occurred.

If it were my cell, I would clean it up and apply some anti corrosion liquid (I use Corrosion Block) to the + nipple. I would then apply a drop of nail polish to the area of the shrink wrap that melted, and see how bad the cell really is.

Set your charger on a heat resistant surface outside and see if the cell will charge. At the end of the charge let the cell sit for 30 minutes, then measure its open circuit voltage.

I have actually seen cells in much worse shape still have 95% of their initial capacity and go on to be used for a long time.

On the other hand, it is possible that the cell is damaged and should be recycled.

I am often amazed as to how much these cells can take. Li-Ion cells perform very well under very large loads, as long as the duration is very short. Since the shrink wrap on the cell is not damaged, it doesn't look like the cell heated up enough to damage the cell.

The biggest problem in future use will be corrosion of the + nipple. The heat may have melted off the plating, and this will add resistance to any circuit you use the cell in.

Looking further into this, if this cell is still working well, AW may give you trade in value on it when you get a replacement for it. He may not have a data point from a shorted cell. No guarantee's, but it may be worth getting in touch with him about it.

Be safe and take care.

Tom

Thanks for the advice! I cleaned it off initially with deoxit red & gold as i don't have any anti-corrosive stuff. It doesn't seem too badly damaged. I tested the resting, open circuit voltage at 4.06v. I will try as you have suggested - will charge them outdoors, leave them for a bit and see how they are later on. I won't use them under high currents for now, though, but just confirming- the worst which could happen is that they 'burst & leak'? no explosions at least? I'll handle them w/ some heavy duty gloves and goggles. Thx for all the advice!

Sorry for any potential grammar errors, typed this from my cellphone.
 

pseudoblue

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Hey, sorry to hear about your situation, I know you've been waiting for these a long time. And it could have happened to any of us. Even I take for granted to switch module with the batteries in.

I have had cases with unusually tall B+ springs that "fold" over and become dislodged to the side when compressed.
Kramer might be right on this part, when you tightened the module in, the springs might have pushed to the sides touching both the battery positive end, and a resting ring which connects to the body. When you twist the tailcap to on, you completed the connection accidentally.

I remember reading on LF's instruction sheet to remove that "resting ring" inside the body for certain modules, maybe the ones without a -'ve spring as Linger mentioned? Or was it for longer modules... I'll have to check. Also will do some connetivity tests on my SP-9 body with my DMM tonight if I can. Would like to narrow down the caused of it.
 

hoongern

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Hey, sorry to hear about your situation, I know you've been waiting for these a long time. And it could have happened to any of us. Even I take for granted to switch module with the batteries in.

Kramer might be right on this part, when you tightened the module in, the springs might have pushed to the sides touching both the battery positive end, and a resting ring which connects to the body. When you twist the tailcap to on, you completed the connection accidentally.

I remember reading on LF's instruction sheet to remove that "resting ring" inside the body for certain modules, maybe the ones without a -'ve spring as Linger mentioned? Or was it for longer modules... I'll have to check. Also will do some connetivity tests on my SP-9 body with my DMM tonight if I can. Would like to narrow down the caused of it.

For clarification (I wonder if it has anything to do with this as well) - I normally use a large negative spring mentioned earlier on outer part of the D26 module when using it in my flashlight. However, on this occasion, I forgot to put in the large spring so it was only using the positive (smaller, inner) spring. Whatever it was, it must have completed the circuit.

I can't really seem to remember the "resting ring" instructions (I did read them though, maybe not carefully enough?), I'll go check that when I get back from work.

Either way, the best solution is to remove the cells first!
 

hoongern

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Well, I must say that this turned out better than it may have.

I confirmed with AW that the damage to the cell is electrolyte leakage, and that I should not use the cell anymore. He said that the other cell should be fine as long as it doesn't leak, I will continue to monitor it over the next couple of days.

But meanwhile, FiveMega has agreed to send me a new spring, AW offered me a decent discount on 18500 replacements, and LumensFactory has given me a very good deal on replacement twisty switches.

So, I gotta really give it to those guys for their generally prompt and AWESOME customer service! lovecpflovecpflovecpf

Hopefully this turns out well :) It was still a costly accident, but hopefully it won't repeat itself again!

And for future reference: You can never be too careful with high-powered setups! Always remove the batteries when replacing modules, check the springs to make sure they are aligned correctly, and when replacing bulbs, use goggles (Hmm.. I should probably use proper goggles instead of swimming goggles?), and I also use heavy duty gloves, even though it takes more time.

IMR cells have HUGE current output potential, so treat them with care!

I've learned quite a bit from this experience, and I hope others will do so as well!
 

Black Rose

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Glad things worked out well.

A big :thumbsup: to FiveMega, AW, and LumensFactory.

It's great to see that type of support from these very popular CPF vendors.
 

SirJMD

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High-power cells + short circuit = bad :D

Reminds me of a tale from my when my dad was in the air force.. a screwdriver was accidently dropped on a 200A high-voltage rail. Puff and it was gone - nothing left at all.
 

hoongern

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You know, I've been wondering what is the worst which would happen to an IMR cell after this kind of damage. Since it still reads a voltage, I tried doing an outdoors discharge for a couple seconds with both of the cells, and it worked fine. (Batteries not sealed in flashlight, for safety)

Would playing with damaged IMRs be potentially dangerous? I mean - I hear about them being safe chemistry, so unless they leak, I'm not sure what else could happen. Anyone knows?
 

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