Question on Mosfet for super sub-ohm Lipo box

[Spartan1976]

Hey everyone!! I searched and searched, and I can't find an answer to my question.

I'm building a Lipo box using a 5000mAh 7.4v 75C cont 150C burst Lipo pack, and I really need to know what to do about a Mosfet for it. I've used several of the standard 3034 mosfets for regular 18650/26650 mods, but considering that this battery is capable of pushing 750amps, I know the 3034 won't stand up to that kind of abuse. I'm wanting to push my super-sub-ohming down to 0.02 or even 0.01 ohms....and I know that will pull massive amperage.

I'm going to use Deans connectors for the battery, and 14gauge silicone high temp wire to a Fat Daddy Vapes V4 510 connector, and a Lipo battery alarm/monitor inside the box.

Does anyone have an input on this, or experience in the matter? Thanks!

 

[pony]

You may have trouble finding someone to chime in on this. Just knowing that you plan to go that low is going to make folks nervous. It in a litigeous world we live in and nobody wants to get sued if something goes south.

 

[Spartan1976]

Yeah, I hear you......it's really more about the device being ABLE to go that low and not kill me....not about me aiming to actually consistently vape that low. LOL

How about this then....my electronics isn't terribly advanced......if I add a 30amp capable toggle switch to the negative leg of the system, to act as a master power switch in case of "incident".....would it work fine and allow the system to operate at above that 30amp point, or would it fuse together, or not work at all....any ideas?

 

[Rommel]

That whole idea is unnerving and scary. So much power with so little ohms in your hands is just insane. And when you say your electronics are not terribly advanced makes me think you should not be building something like that.

 

[Spartan1976]

I understand. I've built boxes....just not like this. Honestly, the whole Lipo concept is not a scary thing, when you look at it from the standpoint that there is more headroom, and margin for error than with a standard dual parallel or series box mod, because of the natively higher voltage and amperage capability. Someone running a 0.1ohm coil setup (which happens all of the time) on a box with two Sony VTC5s in it, is inherently dangerous, because of the low (relatively) capability of those batteries.

On the other hand, the same coil setup with a battery like I have is a walk in the park for that battery. It's nowhere near the continuous amp output of the battery.

There's potential to push anything further than it needs to go, and vaping on anything lower than one ohm is "dangerous". I'm going to build the box regardless, and I'm not intending to push it's limits, but I would like to build it so that the entire system is capable of handling what the battery can deliver. I'd appreciate the help, but if you don't want to, that your prerogative.

 

[Rommel]

Yeah. Without experience with that kind of power output i rather not "help" by guessing.

 

[pony]

I guess the root of it less could you than should you.

 

[Spartan1976]

Ok, so if you were going to place a master power switch on a box mod that you were going to vape at say 0.1ohm, or around 50-60 amps....what switch would you use?

 

[Wabah58]

Ok, so if you were going to place a master power switch on a box mod that you were going to vape at say 0.1ohm, or around 50-60 amps....what switch would you use?

You can get by with a very small switch if you install it between G (Gate) of mosfet to switch.

 

[MKPM]

Not even at that resistance sir. There are some box modding forums and lists out there that might help you.....I know I wont.

 

[MKPM]

I have a few mates that win cloud comps on a monthly basis using single and dual 18650 mechs with .16 builds....just saying. The secret is in the coil build/atomiser design/technique......not the mod.

 

[MKPM]

I will add this bit of advice and that is all. Get a pair of calipers and measure the thickness of your LiPo pack. Vaping at that low a resistance is damaging to that style of battery and you WILL WANT TO KNOW if it is swelling at all. If it does start to swell, bin it and consider it a lesson learned.

 

[Warhawk-AVG]

Hey everyone!! I searched and searched, and I can't find an answer to my question.

I'm building a Lipo box using a 5000mAh 7.4v 75C cont 150C burst Lipo pack, and I really need to know what to do about a Mosfet for it. I've used several of the standard 3034 mosfets for regular 18650/26650 mods, but considering that this battery is capable of pushing 750amps, I know the 3034 won't stand up to that kind of abuse. I'm wanting to push my super-sub-ohming down to 0.02 or even 0.01 ohms....and I know that will pull massive amperage.

I'm going to use Deans connectors for the battery, and 14gauge silicone high temp wire to a Fat Daddy Vapes V4 510 connector, and a Lipo battery alarm/monitor inside the box.

Does anyone have an input on this, or experience in the matter? Thanks!

Just because the battery/power source can push 750A doesn't mean it will push that...no nichrome wire will be able to handle that current. Use the 3040, it will handle all you can throw at it thru your coils.

you will get .02-.01 ohms resistance in the wiring...let alone thru the coil, if you mean .2-.1 then do the math on the wattage

Even if everything was perfect and you weren't loosing anything thru the connections/solder joints/springs/wires, a .1ohm coil at 7.4vdc would pull 74A and develop 547~ watts...but I guarantee it would turn the coil red like a lightbulb and open itself up (aka burn thru) long before you got a good vape off of it.

 

[BigNasty]

So you want a gnats nut hair away from dead short and near instant KABOOM in your face... gotcha.

 

[Spartan1976]

I've got a Mutation X v2 Plus running dual parallel 4 wrap 22g nichrome coils at 0.04 ohm on a dual parallel 18650 mech box mod right now.....using two Samsung 25Rs with 100amp burst. The batteries get warm, and I don't like that....that's why I'm building the Lipo box.

I got it solved though.....I ordered an RC plane arming switch, which is literally a Deans Ultra connector, that mounts to the side of the box, and if you want to kill the power, you simply pull the connector. Like a breaker, except it's not fused. Done deal.

Considering this site is called "Vaping Underground", you guys are not very "edgy". I really thought you guys would have all been pushing the boundaries.....or at least welcoming to people that do. LOL

 

[Rommel]

I will add this bit of advice and that is all. Get a pair of calipers and measure the thickness of your LiPo pack. Vaping at that low a resistance is damaging to that style of battery and you WILL WANT TO KNOW if it is swelling at all. If it does start to swell, bin it and consider it a lesson learned.

Bit off topic, but thats alright. In my line of work i am daily in contact with people from all around the world, and the british accent with words like bin instead of trash are tripping me over all the time. Its easier to communicate with an old chinese lady that doesnt undestand anything but mandarine than it is with someone who has a strong scottish/british/irish accent.


Dont get me wrong, i love listening those accents, but sometimes its completely incomprehensible.

 

[Spartan1976]

I'm British too Rommel.

But I agree with you mate! I've been living in the states for 20 years though, so I'm so "Americanized" that you wouldn't have any problem understanding me.

FYI though, Australians say "mate" too. ;-)

 

[pony]

Considering this site is called "Vaping Underground", you guys are not very "edgy". I really thought you guys would have all been pushing the boundaries.....or at least welcoming to people that do. LOL

Its not that we arent "edgy", i know exactly how id build such a box. My quandry is do i just tell you and help you not blow your face off or do i get socratic and let you learn from your own adventures.
When you open dialogue with "my electronics skills arent that strong" most people are going to see someone used to playing with bottle rockets wanting to step up nucular armaments.this is one time i agree with the 'go study it' mentality for which that other place is so famous.

 

[Rommel]

I'm British too Rommel.

But I agree with you mate! I've been living in the states for 20 years though, so I'm so "Americanized" that you wouldn't have any problem understanding me.

FYI though, Australians say "mate" too. ;-)

Oh yeah, aussies. Thats not an accent, its an entire language.

 

[BoomStick]

You gonna be able to break the connection when the components are welded together? What you are attempting is not flirting with the edge. You're venturing way past that. You should find an electrical engineer to bounce your ideas off of. A professional expert, not vaping hobbyists.

 

[Spartan1976]

Its not that we arent "edgy", i know exactly how id build such a box. My quandry is do i just tell you and help you not blow your face off or do i get socratic and let you learn from your own adventures.
When you open dialogue with "my electronics skills arent that strong" most people are going to see someone used to playing with bottle rockets wanting to step up nucular armaments.this is one time i agree with the 'go study it' mentality for which that other place is so famous.

I know where you're coming from. I'm a bit different in that respect. I used to build and fly RC helicopters/cars with Lipos, build electric airsoft rifles with Mosfets and Lipo batteries, do full reball repairs on PS3s and Xbox 360s (as well as mod/flash them), I build and repair computers for a living, and now I also build vape coils and boxes everyday.....BUT my electronic theory does not extend to this particular point....because of the level of potential power handling we're talking about with this one.

I know that I can usually place a switch anywhere in a circuit, and it will ordinarily be fine in a "normal" setup......even when using a Lipo, because we're not usually talking about far exceeding the amperage capacity of a switch. My helis used 12-20C lipos, and the switches, wires, and connectors I used were all capable of that kind of current. In this case, even though I know that the potential amperage far exceeds the "rating" of ANY wiring and/or connector that I could place in a reasonably sized mod box, I don't want my switch (which is supposed to be my safety cut off) to be the amperage bottle-neck in the system, because that's not the point I want to fail....obviously.

What I don't understand....again because I've never even had to contemplate it.....is that if I were to place a 30amp switch, on the negative leg of the battery wiring, would it survive at reasonable amperages....that may still end-up being above what the switch is rated for.....because it resides "behind" the Load in the system. In other words, because it's after the atomizer in the circuit, does that mean that the current reaching it, would be reduced enough to where it wouldn't instantly fuse the switch.

And you're right BoomStick.....if the "kill plug" fuses, I'm just as screwed.

 

[BigNasty]

I've got a Mutation X v2 Plus running dual parallel 4 wrap 22g nichrome coils at 0.04 ohm on a dual parallel 18650 mech box mod right now.....using two Samsung 25Rs with 100amp burst. The batteries get warm, and I don't like that....that's why I'm building the Lipo box.

I got it solved though.....I ordered an RC plane arming switch, which is literally a Deans Ultra connector, that mounts to the side of the box, and if you want to kill the power, you simply pull the connector. Like a breaker, except it's not fused. Done deal.

Considering this site is called "Vaping Underground", you guys are not very "edgy". I really thought you guys would have all been pushing the boundaries.....or at least welcoming to people that do. LOL

Honestly on the practical safety side you are playing russian roulette with a loaded gun, it is not a if it will blow your hand and face off but when.
Edgy has zero to do with safe or sane, anything really below .1 is flirting with dead short kaboom ville. No amount of tech gizmos and build are going to put you into a safe zone lap dancing with a dead short, it puts you into the walking Darwin award.

 

[MKPM]

Bit off topic, but thats alright. In my line of work i am daily in contact with people from all around the world, and the british accent with words like bin instead of trash are tripping me over all the time. Its easier to communicate with an old chinese lady that doesnt undestand anything but mandarine than it is with someone who has a strong scottish/british/irish accent.


Dont get me wrong, i love listening those accents, but sometimes its completely incomprehensible.

Fair play that. In my defence, I have lived here in the Rebel colonies long enough to have assimilated somewhat without completely losing my sense of provenance. I paid a couple of thousand to have my accent softened to the level of near nonexistance.


Sent from my iPhone 6 using Tapatalk

 

[Rommel]

Fair play that. In my defence, I have lived here in the Rebel colonies long enough to have assimilated somewhat without completely losing my sense of provenance. I paid a couple of thousand to have my accent softened to the level of near nonexistance.


Sent from my iPhone 6 using Tapatalk

Haha, okay. I work as a security officer at an airport, so i meet all kinds of accents and languages there. Brits are always laughing at me for misunderstanding them. But im a finn, so thats my defense.

 

[BoomStick]

If you use electron flow theory instead of hole flow, the current is supplied by the negative. Also, current is common in a series circuit. Where the switch is in the circuit is irrelevant with regards to what the switch can handle if it's in series with the the circuit.

 

[Spartan1976]

Honestly on the practical safety side you are playing russian roulette with a loaded gun, it is not a if it will blow your hand and face off but when.
Edgy has zero to do with safe or sane, anything really below .1 is flirting with dead short kaboom ville. No amount of tech gizmos and build are going to put you into a safe zone lap dancing with a dead short, it puts you into the walking Darwin award.

I know buddy....I really appreciate your concern, but I really do understand the risks, and I'm a 38 year old man with a life insurance policy.

 

[MKPM]

Haha, okay. I work as a security officer at an airport, so i meet all kinds of accents and languages there. Brits are always laughing at me for misunderstanding them. But im a finn, so thats my defense.

Oh I was incomprehensible when I first moved here. I am from Wick which is north of Inverness. I spoke quite fast and in the local dialect. Took elocution classes to tone it down a wee bit. Then further courses with a personal coach to eliminate it.


Sent from my iPhone 6 using Tapatalk

 

[Spartan1976]

Thanks everyone!!! I'll post pics up when I'm done with it.

 

[Warhawk-AVG]

I've got a Mutation X v2 Plus running dual parallel 4 wrap 22g nichrome coils at 0.04 ohm on a dual parallel 18650 mech box mod right now.....using two Samsung 25Rs with 100amp burst. The batteries get warm, and I don't like that....that's why I'm building the Lipo box.

I got it solved though.....I ordered an RC plane arming switch, which is literally a Deans Ultra connector, that mounts to the side of the box, and if you want to kill the power, you simply pull the connector. Like a breaker, except it's not fused. Done deal.

Considering this site is called "Vaping Underground", you guys are not very "edgy". I really thought you guys would have all been pushing the boundaries.....or at least welcoming to people that do. LOL

Are you sure you ain't at .4 (4 tenths) ohms not .04 (4 hundreds) ohm...that is more or less a dead short bro

 

[Rommel]

With that build the ohms should come out at 0.04 rather than 0.4. And yes, its close to a dead short and IMO not even necessary.

In theory thats more than 105 amps and 440w...

Just imagine Whats going on in the 510 connector with those currents. Definetely not designed for that.

 

[Wabah58]

I''l leave this hear!

 

[pony]

I''l leave this hear!

you tease

 

[A10EN]

I'll start by saying I have no interest in building, but is the big concern here in the batteries? If so. Why not run of an auto batt and potentiometer to get volts down. 500 cca bat, and industrial switches and a long tube from atty to mouth.
But I got away ffom inhaling smoke and cotton can't be better then tobacco :/

 

[MrScaryZ]

Hey everyone!! I searched and searched, and I can't find an answer to my question.

I'm building a Lipo box using a 5000mAh 7.4v 75C cont 150C burst Lipo pack, and I really need to know what to do about a Mosfet for it. I've used several of the standard 3034 mosfets for regular 18650/26650 mods, but considering that this battery is capable of pushing 750amps, I know the 3034 won't stand up to that kind of abuse. I'm wanting to push my super-sub-ohming down to 0.02 or even 0.01 ohms....and I know that will pull massive amperage.

I'm going to use Deans connectors for the battery, and 14gauge silicone high temp wire to a Fat Daddy Vapes V4 510 connector, and a Lipo battery alarm/monitor inside the box.

Does anyone have an input on this, or experience in the matter? Thanks!

You are freaking out of your mind have you plugged the numbers in on what amps you need to do a .01 build I think you are just nutz firstly if you understand LIPO technology and are going to take the risks with that you seem to be so articulate and no so much but having problem with a Mosfet come on man do search for Mosfet you will find the answer... its just beyond silly you do want to blow yourself up if you want me to I can do it for you before you even build this.. I will buy you a planet ticket down here to good ole Texas and blow you up unless this is a suicidal tendency hahaha wowzy

 

[tj138waterboy]

Did this build ever happen? I'm looking to do a dual 7.4v lipo in parallel but only want to do it for battery life and to to drop to around a .3 ohm coil.

 

[Jackson]

Hey everyone!! I searched and searched, and I can't find an answer to my question.

I'm building a Lipo box using a 5000mAh 7.4v 75C cont 150C burst Lipo pack, and I really need to know what to do about a Mosfet for it. I've used several of the standard 3034 mosfets for regular 18650/26650 mods, but considering that this battery is capable of pushing 750amps, I know the 3034 won't stand up to that kind of abuse. I'm wanting to push my super-sub-ohming down to 0.02 or even 0.01 ohms....and I know that will pull massive amperage.

Interesting, so basically you want to vape @ 5000W? Good luck with that.

If you keep the 3034 well ventilated and use a heat sink you should be able to get short bursts at that amperage, the datasheet claims Pulsed Drain Current @ 1372A, so half of that seems doable. Can you do more than a short burst at 5000W anyway?

That said you could use 2 in parallel, would be best to use a perfectly matched pair. Don't stack them on top of each other (again to avoid heat issues).

http://www.irf.com/technical-info/appnotes/an-941.pdf

This guy likes it.

Note, you'll need a mix your juice by the quart.

 

[Anus Braun]

I understand. I've built boxes....just not like this. Honestly, the whole Lipo concept is not a scary thing, when you look at it from the standpoint that there is more headroom, and margin for error than with a standard dual parallel or series box mod, because of the natively higher voltage and amperage capability. Someone running a 0.1ohm coil setup (which happens all of the time) on a box with two Sony VTC5s in it, is inherently dangerous, because of the low (relatively) capability of those batteries.

On the other hand, the same coil setup with a battery like I have is a walk in the park for that battery. It's nowhere near the continuous amp output of the battery.

There's potential to push anything further than it needs to go, and vaping on anything lower than one ohm is "dangerous". I'm going to build the box regardless, and I'm not intending to push it's limits, but I would like to build it so that the entire system is capable of handling what the battery can deliver. I'd appreciate the help, but if you don't want to, that your prerogative.

Good luck, with your experimentation...I suppose somebody has to 'stand on the tracks', not knowing the schedule..

 

[Anus Braun]

You are freaking out of your mind have you plugged the numbers in on what amps you need to do a .01 build I think you are just nutz firstly if you understand LIPO technology and are going to take the risks with that you seem to be so articulate and no so much but having problem with a Mosfet come on man do search for Mosfet you will find the answer... its just beyond silly you do want to blow yourself up if you want me to I can do it for you before you even build this.. I will buy you a planet ticket down here to good ole Texas and blow you up unless this is a suicidal tendency hahaha wowzy

Metal Oxide Semi-conductor Field-Effect Transistor..wish I remembered how the device operates..

 

[T702]

So 35 Bonners chimed in to cry and nobody has any knowledge on the topic...is this ECF I thought I was on vu...

 

[vaping_jake]

Actually there was plenty of sound knowledge and advice.here. It has been 4 months since the OP said he will post pics of his build, hope all is well.

 

[tj138waterboy]

http://breaktru.com/smf/index.php/topic,1511.0.html
I somewhat attempted this build but only went down to .5 ohms on 26 gauge kanthal. Almost 150 watts @ 17 amps. My parallel cutoff fuses are rated 9 amp each so 18 amp cutoff. For this build to even be vapable you need like a 1.5 ohm parallel coil or 4 ohm single. Unless you enjoy 1/2 second hits.