Explosion at my local shop

[Bad Ninja]

I've asked this question many times with (IMHO) weak or unresponsive answers! The biggest thing to understand is vaping is a very "PERSONAL" thing & although I completely don't understand the logic behind I respect peoples right to choose! The thing I wish is that we ensure that the person purchasing the device (especially hybrids) knew how to use them. But I still haven't figured out how to do this without inviting the gov't to issue licenses! And for me that's a no way!

I've never seen a vaper that fully understands how to use a mechanical
mod suggest regulations.

People fear what they don't understand.

Example: "hybrids" are probably the safest mechs, as they have a dedicated atomizer. Hybrids don't have 510 threads, so you can't put the wrong atty on one and short the battery.
"Hybrid-look" mods or "direct-to-battery" mods are the ones that require special attention by the user.

Know your gear and you won't fear it.

 

[Bad Ninja]

No you're just a clown! LOL!

 

[roxynoodle]

I have a clone Tuglyfe box. Love it. Its not a mechanical (well, mine isn't). Its a dual parallel, unregulated mod with a MOSFET.

I'm not sure what may have went wrong here. Battery wrapper torn or battery/ies in upside down? Unregulated mods usually don't have reverse battery protection.

 

[Bad Ninja]

I have a clone Tuglyfe box. Love it. Its not a mechanical (well, mine isn't). Its a dual parallel, unregulated mod with a MOSFET.

I'm not sure what may have went wrong here. Battery wrapper torn or battery/ies in upside down? Unregulated mods usually don't have reverse battery protection.

You may have hit the nail on the head with the reverse battery placement.

 

[roxynoodle]

You may have hit the nail on the head with the reverse battery placement.

Definitely have to pay attention. I have quite a few dual battery mods these days, and they are all different.

 

[HauntedMyst]

I can verify with 100% assurance that I have never seen Bad Ninja chase a clown

That's only because you have never seen him drunk and horny after sitting through the circus. It's like watching Charlie Sheen when he's off his meds.

 

[Ryedan]

I have a clone Tuglyfe box. Love it. Its not a mechanical (well, mine isn't). Its a dual parallel, unregulated mod with a MOSFET.

I'm not sure what may have went wrong here. Battery wrapper torn or battery/ies in upside down? Unregulated mods usually don't have reverse battery protection.

Thanks for finally inserting some common sense into this thread roxy . I don't know the Tuglyfe box mod so I looked it up after reading the OP and found out the authentic and one clone I came across used MOSFETs. That doesn't mean this mod had one, but it could (should) have. A lot of folks seem to be so agenda driven on this topic they aren't interested in the actual details

I have no interest in MOSFETs so I've never researched them beyond a very basic understanding but I imagine they don't have a failure mode that shorts the battery if the battery is inserted the wrong way and/or has a torn wrapper, or there would have been a lot of vented batts out there by now . OTOH, maybe I'm missing something so if you or anyone is familiar with them please correct me if I got that wrong. Are there any failure modes that could have caused this to happen?

These stories rarely have enough information for us to figure out what went wrong with any degree of certainty. We know the battery vented very quickly. With proper batteries that generally only happens in a mod when a battery is severely shorted, but it generally doesn't happen almost instantly and there is very rarely any flame. An internal short in the batt will cause it to vent quickly, but that should only happen if the battery was damaged or was a bad battery from the factory and in these cases all bets are off and the battery isn't safe in any mod.

Ultimately though for the battery to vent with flame so quickly IMO there was something wrong with it. I have always bought only manufacturer branded or AW batts so I would have that safety factor when I use both mechs and regulated mods.

 

[roxynoodle]

Thanks for finally inserting some common sense into this thread roxy . I don't know the Tuglyfe box mod so I looked it up after reading the OP and found out the authentic and one clone I came across used MOSFETs. That doesn't mean this mod had one, but it could (should) have. A lot of folks seem to be so agenda driven on this topic they aren't interested in the actual details

I have no interest in MOSFETs so I've never researched them beyond a very basic understanding but I imagine they don't have a failure mode that shorts the battery if the battery is inserted the wrong way and/or has a torn wrapper, or there would have been a lot of vented batts out there by now . OTOH, maybe I'm missing something so if you or anyone is familiar with them please correct me if I got that wrong. Are there any failure modes that could have caused this to happen?

These stories rarely have enough information for us to figure out what went wrong with any degree of certainty. We know the battery vented very quickly. With proper batteries that generally only happens in a mod when a battery is severely shorted, but it generally doesn't happen almost instantly and there is very rarely any flame. An internal short in the batt will cause it to vent quickly, but that should only happen if the battery was damaged or was a bad battery from the factory and in these cases all bets are off and the battery isn't safe in any mod.

Ultimately though for the battery to vent with flame so quickly IMO there was something wrong with it. I have always bought only manufacturer branded or AW batts so I would have that safety factor when I use both mechs and regulated mods.

I'm not an expert, but I think the only thing a MOSFET really does is protect the switch. It can handle a lot more current than the switch can. It should prevent the switch from needing replacement all the time or autofiring.

However, I'm not sure it does anything else really as far as offering the user any protection.

I'm not sure who is an expert on MOSFETs here. Maybe @Mooch can give a better explanation?

 

[WattWick]

Bah, the usual suspects appear here immediately to defend mech mods. Hey crx, you mentioned that the user broke "rule #1". Where exactly is this compendium of rules located so the rest of us can study and memorize them? It could save someones life someday.

What you see as 'jumping to defend mech mods', I see as experienced, safety minded vapers defending themselves from knee-jerk, inflammatory condescension.

It is disgruntling to see opportunities to learn and improve instantly and inevitably turning into flamewars; I dare say by 'usual suspects'. Anything worth taking away from these "sky is falling" threads ends up buried in several pages of pointlessness. Something which, I am sad to admit, I just added to.

In other words: Can you please consider not trolling next time an accident thread pops up? Accidents happen. That's sort of why we have a word for it.

 

[Mooch]

Just a few thoughts to toss imto the mix...

The MOSFET only protects the firing button/switch, nothing else. It might be possible to size it to blow apart before a particular battery vented but that doesn't sound very realistic.

A MOSFET typically fails closed. That is, it thinks it's a piece of wire and will not open the circuit until it has heated enough to pop apart.

A MOSFET will conduct in reverse no matter what the button position is. If the battery is inserted reversed then a particular structure in the MOSFET, the body diode, will conduct. This body diode gets much hotter than the MOSFET does when comducting current in the "forward" direction. This extra heating can easily damage the MOSFET, cause it to fail closed, or cause it to pop.

 

[Ryedan]

Just a few thoughts to toss imto the mix...

The MOSFET only protects the firing button/switch, nothing else. It might be possible to size it to blow apart before a particular battery vented but that doesn't sound very realistic.

A MOSFET typically fails closed. That is, it thinks it's a piece of wire and will not open the circuit until it has heated enough to pop apart.

Thanks for helping out Mooch

OK, so what I get from 'fail closed' is that it will conduct without the mod's switch pressed, but not without an atty on the mod, correct? IOW, it doesn't short the battery in this case.

A MOSFET will conduct in reverse no matter what the button position is. If the battery is inserted reversed then a particular structure in the MOSFET, the body diode, will conduct. This body diode gets much hotter than the MOSFET does when comducting current in the "forward" direction. This extra heating can easily damage the MOSFET, cause it to fail closed, or cause it to pop.

Again, it sounds like this failure mode will not short the battery, correct?

Or did I get it all wrong

 

[Mooch]

Thanks for helping out Mooch

OK, so what I get from 'fail closed' is that it will conduct without the mod's switch pressed, but not without an atty on the mod, correct? IOW, it doesn't short the battery in this case.

Correct.
It will act as a solid piece of wire, allowing current to flow through the MOSFET to wherever it can flow. No current should flow though of the mod is correctly wired, functioning properly, and no atty is present.

Again, it sounds like this failure mode will not short the battery, correct?

Or did I get it all wrong

Correct.
If everything is wired and working properly except the MOSFET it won't on its own short the battery or do anything except act as a piece of wire (until it pops).

 

[Ryedan]

Correct.
If everything is wired and working properly except the MOSFET it won't on its own short the battery or do anything except act as a piece of wire (until it pops).

So if the MOSFET is wired so the battery contacts are reversed it would function properly, IOW close the circuit when you hit the switch, but could eventually pop. When it pops would it short the battery?

Is there any other way it could short the battery?

 

[Mooch]

So if the MOSFET is wired so the battery contacts are reversed it would function properly, IOW close the circuit when you hit the switch, but could eventually pop. When it pops would it short the battery?

Is there any other way it could short the battery?

Not sure I understand you. If the MOSFET is wired in correctly but the battery is reversed, current will flow the same was as if the MOSFET was replaced by a piece of wire.

If the MOSFET was wired incorrectly so that the battery was reversed if it was placed in the sled correctLy, then it might not fire, it might fire continuously, or it might pop. Not sure, depends on how it was wired incorrectly.

If the MOSFET metal "tab", or its metal back, was touching the case then there's a chance the battery could be shorted.

 

[Bunnykiller]

Im wondering if the gate resistor went bad/shorted on the case.....

 

[Bunnykiller]

been thinking this thru a bit more.... even if the Mosfet failed closed it would act if the switch was stuck on. That would be like just holding the switch on... for the battery to vent almost immedietly would require a hard short, a connection to the case and positive lead... ( presuming the case was at negative potential)
what Im also wondering about is the time involved in the insertion and venting... of all the videos etc, it takes over a 50 seconds to develope enuf heat in the battery to vent it... altho I did see one video of a venting occur with an ICR that took about 33 seconds with a hard short...
Im wondering if the battery was already damaged before placement and it was already on the verge to go....

 

[Mooch]

Possibly.
But there are videos of almost instant venting and even of some very short delays to thermal runaway. I do 't have any links though.

 

[suprtrkr]

Thanks for finally inserting some common sense into this thread roxy . I don't know the Tuglyfe box mod so I looked it up after reading the OP and found out the authentic and one clone I came across used MOSFETs. That doesn't mean this mod had one, but it could (should) have. A lot of folks seem to be so agenda driven on this topic they aren't interested in the actual details

I have no interest in MOSFETs so I've never researched them beyond a very basic understanding but I imagine they don't have a failure mode that shorts the battery if the battery is inserted the wrong way and/or has a torn wrapper, or there would have been a lot of vented batts out there by now . OTOH, maybe I'm missing something so if you or anyone is familiar with them please correct me if I got that wrong. Are there any failure modes that could have caused this to happen?

These stories rarely have enough information for us to figure out what went wrong with any degree of certainty. We know the battery vented very quickly. With proper batteries that generally only happens in a mod when a battery is severely shorted, but it generally doesn't happen almost instantly and there is very rarely any flame. An internal short in the batt will cause it to vent quickly, but that should only happen if the battery was damaged or was a bad battery from the factory and in these cases all bets are off and the battery isn't safe in any mod.

Ultimately though for the battery to vent with flame so quickly IMO there was something wrong with it. I have always bought only manufacturer branded or AW batts so I would have that safety factor when I use both mechs and regulated mods.

A MOSFET (Metal Oxide Semiconductor/Field Effect Transistor) is an electronics part that is like any other transistor. It has a current path (source and drain) where the current it is switching or amplifying goes through the part, and a third contact (gate) which "turns on" the current path. (It is quite similar in function to a mechanical relay when used as a switch, except it's electronic). They can be used as an amplifier because they will tolerate much more current between the source and drain that it takes to tickle the gate, and they don't have to turn on "all the way,"--the resistance in the source-drain path varies with gate voltage-- but this is meaningless for vape mods. In mods, they are electronic switches and nothing more. You apply voltage to the gate and the switch turns on (or off, there are two kinds and they work backwards to each other) allowing the battery to fire the atty. Take voltage off the gate and the switch turns off (or on, as above). Their real purpose in vape mods is make it possible to switch high currents. It isn't easy to buy a pushbutton switch rated better than 10 amps that will fit in a mod. Higher rated buttons are big. Thus you can use a tiny pushbutton to switch the gate current, which is usually milliamps or even microamps, and let the MOSFET switch the power load. If you are building a really powerful box mod-- 4 batteries and I saw an idiot with 6 once-- you can use the same pushbutton to switch on more than one MOSFET and divide the load between to stay within their capacity.

 

[JMarca]

A "safe" mech would require a mosfet (switch protection) with a resistor, a fuse so you don't blow your brains out if you install batteries incorrectly and finally an optional master on/off switch so you don't castrate yourself.

OR...

You can use common sense.

 

[zoiDman]

if they ban mech mods I guess we will just have to start making our own. ...

If?

Does anyone Really Believe that Mech Mods will be allowed to be sold once the FDA Regulates the e-Cigarette Market?