ATTN: Modders - be VERY CAREFUL!

[Ripley]

Here are the specs,

Standard no-LED magnum mod
tire-chuck adapter for 901
2x CR2, 3V, 800 Mah (Made in China for $1/each .. NOT Deal Extreme batts)

Not sure what happened, all circuits/switches/voltage verified. Vaped a couple times great, then no vape, puffed a few times then ** POP.. FIZZ **. The finger that was on the switch was covered in black stuff, and is now sportin' a 2nd degree burn. The sucker caught on FIRE. The batts are my first suspect.

Good news is that my favorite atomizer didn't fry in the fire, it was quite the traumatic experience. There were quite a few panic filled moments as my eyesight recovered. Just be aware folks, when you mod, you're putting this thing right next to your face.

 

[GabbyD]

Scary! I'm glad you're okay.

 

[parked]

Oh damn! glad your doing o.k. thanks for the heads up !!

 

[Grumpysanta]

If you used the standard little switch that is usually soldered to a circuit board (like on video recorders) and just has a little black bit that you press then that is what most likely caused the problem. That kind of switch is vastly underated for what we are doing. You need a switch that can handle at least 1 amp, the switched I use can comfortably handle 3 amps. I have warned several times about this in other threads but so far no one seems to listen.

I do not recommend using these switches, they can not handle the current

This is a very small switch and can handle 3 amps, this is much safer

I hope you are ok

 

[Tasdad]

Good news is that my favorite atomizer didn't fry in the fire, it was quite the traumatic experience. There were quite a few panic filled moments as my eyesight recovered.

The real question is...Was it traumatic because you couldn't see, or because you couldn't see if your atomizer was ok?

Seriously, though, glad you're ok.

 

[youfillintheblank]

That sucks rocks! I'd hate losing a good mod like that. Have to find the culprit before a rebuild. I've run 2xCR2 through that same kind of switch with no problems, so has Madog, or at least we've never heard about a massive failure with one of his units. GrumpySanta may be right about the switch, that other microswitch he's showing is very good, but not quite as handy as those little teeny switches. I purposely took my switches out of an old old CD player that was made in JAPAN, not China, for the very reason that the parts inside are probably much better than what we would get today brand new. Switch problems, zero. Vapour, LOTS! Anyways, good luck with the autopsy, and keep some medicated ointment on that finger.

 

[Ripley]

Ok, so let's get into an electrical/safety discussion.

1. How many amps DO these atomizers draw? I've got these same switches on my USB Mods. The usb hub I use is direct power, so it's capable of delivering 5v & 500 mA to any single port. This is why I suspect the batteries.
2. The switches I use (purchased from radio shack) are rated at 50mA. I've also got a few I stripped off a Sony VHS player, but I couldn't tell you which one was on this mod.
3. Possible to put a resistor or regulator between the power in and the switch to prevent this in the future?

When I did the autopsy, the switch button was melted, but everything else seemed intact. The blob in the pic is the hot-glue I used to fasten it to the flashlight circuit board. No melted wires, switch insides seemed ok. Melted button probably due to the heat. PVC Container for the batteries was charred on both ends, and I couldn't get the batteries out. The exposed part of the batteries appear "expanded"

I'm not an electrician, just a hobbyist, so any input to increase safety is appreciated.

 

[Grumpysanta]

OK, down to the nitty gritty. An atomiser at 3.7v draws approximately 1 amp, so a 50mA switch is clearly not meant to take 1 amp (Note- Maddog and Bastage have not had problems so far). This is why my first mod - 4 x AA NimH batteries, High power MosFet transistor and the little switch was used. The Mosfet only required a few mA to switch on. The Torch Mod doesn't really allow fitting a Mosfet, there's not enough room. So a more powerful switch is required for safer opperation as you have found out. That is why I use the micro switch as it is capable if handling 3 amps. note also that none of us have included any safety measures in case of a short circuit in the atomiser. My current observation is that atomisers almost never short circuit, rather they go open circuit when they fail. I feel that the connector from the original battery that we screw our atomisers onto is also dangerous as that could also short circuit, which from your description of the batteries may have happened. I actually dismantle the connector before soldering it as it gets very hot during soldering, this stops the rubber insulation from melting. it's a sod to get back together but I still think its safer that way. Also be aware that there is little room behind the connector so be careful about the wires and switch as you could easily get a short circuit when you put everything together. That said if you do it right then there should be no cause for alarm.

I hope this information helps although I expect Maddog and Bastage to disagree about the switch as they currently have had not problems, all I can say is that those little switches were never meant to take 1 amp or above.

 

[youfillintheblank]

I actually dismantle the connector before soldering it as it gets very hot during soldering, this stops the rubber insulation from melting. it's a sod to get back together but I still think its safer that way. .

(slaps forehead!!!) Why didn't I think of that BEFORE I melted one on my first mod attempt?!?!?!? Good advice, it takes a little swearing to get it back together but damn, that should be step # 1 in any mod.

How did you get that 3amp switch into your flashlight mod?? I saw one whilst parts shopping and almost bought it, but it looked too big to me.

 

[Bastage]

If the switch shorted out, it wouldn't have burned up your batteries like you described. I could imaging the switch shorting out and ruining the atomizer but not the batteries. What you're describing just guessing off-hand sounds like a power to ground short not a short inside the switch. I'm running a big 1a switch in my Husky flashlight mod. My other 2 mods (USB and Screwdriver clone) are using the small switches. Haven't had any problems with them yet. If I do, I'll own up to it. haha

 

[aaa]

Switches rated for low currents have higher contact resistance by default, their contacts have less protection against corrosion, and are made of less temperature resistant plastics. So they can heat up and melt more easily. There is a little chance that a plastic part inside the switch melt, that (because of an unfortunate construction) kept the switch closed, and burned further. Yet, because of the intermittent operation, I do not regard this as much likely in this case.

It is more likely that solely the battery was the culprit. Either because it did not have protection, or it was fauly. I think it could have happened in any appliance (e.g. a lamp) drawing such current, so I would not blame the mod.

Anyway, Madog is right, shorting of the switch could not cause burning, if the batteries had internal protection.

In my mod, I rather avoided the switch (because I could not get a small one with the right current rating), put in a protecting fuse (though it is regarded as unnecessary by most, it comes handy sometimes), and sticked with NiMH batteries.

 

[Grumpysanta]

Agreed the switch looks big but the width is approximatelt the same as the tiny switches you have been using. I use one of the LED's that that we take off the back plate when we mod, as the button for the switch but unlike maddog I did not need to cut it short as maddog did. I used two small screws (similar thread to wood screws) to mount the switch to the back plate, there is sufficient space between the switch and the connector to avoid any short circuits - at least there is on the torch I used.

 

[Ripley]

aaa .. I'm inclined to believe that it was the batteries as well. I've used these switches on a number of USB mods, and a couple of other magnum mods without issues.

I think Grumpy has valid concerns about the underrated switch, but I don't think that was the case here.

The below excerpt is from WIKI about Lithium-Ion Batteries.

"Lithium-ion batteries can rupture, ignite, or explode when exposed to high temperature environments, for example in an area that is prone to prolonged direct sunlight.[44] Short-circuiting a Li-ion battery can cause it to ignite or explode, and as such, any attempt to open or modify a Li-ion battery's casing or circuitry is dangerous. Li-ion batteries contain safety devices that protect the cells inside from abuse, and, if damaged, can cause the battery to ignite or explode."

I makes me wonder if these cheap batts from China meet our safety standards.

 

[LVD]

This is why my first mod - 4 x AA NimH batteries, High power MosFet transistor and the little switch was used. The Mosfet only required a few mA to switch on. The Torch Mod doesn't really allow fitting a Mosfet, there's not enough room.

I always use a 3 Amp surface mounted power transistor and the little tactile switch, since without the transistor those switches do not have a long life span. Those surface mounted types are so tiny you can build them into anything. And to use a 3 Amp to switch 1 Amp no problems with cooling.

BTW I recently shorted one of my mods accidently: a little puff and some smoke - the transistor fried and actually protected the battery like a fuse. I got curious and did the same thing on purpose with a standard 901 battery that was no longer performing very well and exeactly the same thing happened. (short the connections and blow on the led - a sure way to ruin your battery).

DO NOT TRY THIS AT HOME but if you short a lithium for a second it already gets piping hot.

 

[aaa]

LVD: Your solution (e.g. using a bipolar or MOSFET transistor) as switching device in combination with a small switch is the way to go.
Though probably not the switch was the culprit this time, it is not a good practice to use underrated components in any device, as it is a constructional fault.
Concerning the legal aspects: anyone making constructional faults can be made liable for the damages caused by his product. But, if your product has the right construction, such claims are ungrounded.

 

[ainako]

If the switch shorted out, it wouldn't have burned up your batteries like you described. I could imaging the switch shorting out and ruining the atomizer but not the batteries. What you're describing just guessing off-hand sounds like a power to ground short not a short inside the switch. I'm running a big 1a switch in my Husky flashlight mod. My other 2 mods (USB and Screwdriver clone) are using the small switches. Haven't had any problems with them yet. If I do, I'll own up to it. haha

Does that use penstyle atomizer? If it does how did you get a battery fitting off the battery and please, please, please do tell how you did this...please

 

[BarryK]

OK, down to the nitty gritty. .....................High power MosFet transistor and the little switch was used. The Mosfet only required a few mA to switch on. ..............

Being a bit of a dinosaur, I've never had occasion to use MosFets, I was gonna use a 2n3053 or similar to protect the switch but the additional resistors required are going to bulk up the package quite a bit...

I don't really understand what makes MosFets better than a normal bi-polar transistor, I do however, know that they ARE better....

Any information regarding the type used and components required to allow use with low current switches would be greatly appreciated.

Cheers
Barry

 

[Grumpysanta]

BarryK
Being a bit of a dinosaur, I've never had occasion to use MosFets, I was gonna use a 2n3053 or similar to protect the switch but the additional resistors required are going to bulk up the package quite a bit...

I don't really understand what makes MosFets better than a normal bi-polar transistor, I do however, know that they ARE better....

Any information regarding the type used and components required to allow use with low current switches would be greatly appreciated.

Mosfets are much easier to handle, you only require a 1M ohm resister for the Mosfet to switch properly. Because you are switching the Mosfet hard on the Mosfet does not dissipate any heat so they are ideal for our applications because you don't need extra heatsinks like you would with a standard transistor. The only problem is that Mosfets don't switch well below 4V.

 

[BarryK]

Thanks Grumps,

Seems like a plan, I'll take a look at some data sheets, I guess I'll only need a MosFet capable of switching a couple of amps max?

Cheers
Barry

 

[Bastage]

Does that use penstyle atomizer? If it does how did you get a battery fitting off the battery and please, please, please do tell how you did this...please

I'll be posting up a video of it as soon as I can but I've been working a lot of hours and haven't found the time yet. My SD clone uses a 901 connector but I will be making one that uses the Penstyle as well. The mod would be the same with either one, you would just use whatever connector you prefer. It's easy to remove the connector from a battery all you need to do is pinch it with lock grip pliers below the connector a few times and it'll pull right out the top.