Reviving dead single 18650 box mod

[FluidExtractor]

So my box died a while ago and I decided to transform it into unregulated box with a MOSFET.

The wiring looks like this with an added voltmeter.

I wired everything just like in the diagram with 13ga wire with the exception of the switch (lower gauge there, not sure about the exact number). It kinda works but I can't get the coils to heat up in a reasonable amount of time. To get any amounts of vapor I would need to hold the button for 10+ secs. Everything is soldered and heat shrink wrapped to the best of my abilities.

Any ideas on how to solve this problem? I saw an old thread here where someone had this exact same problem. He also used the same MOSFET. So is a single 18650 not good enough for IRLB3034 ?

 

[Baditude]

It kinda works but I can't get the coils to heat up in a reasonable amount of time. To get any amounts of vapor I would need to hold the button for 10+ secs. Everything is soldered and heat shrink wrapped to the best of my abilities.

Any ideas on how to solve this problem? I saw an old thread here where someone had this exact same problem. He also used the same MOSFET. So is a single 18650 not good enough for IRLB3034 ?

A lot depends upon the specifications of the 18650 battery you are using (especially the amp rating) and the resistance of the coil you are trying to fire.

So I need to ask you what is the CDR (continuous discharge rate, or amp rating) of your battery and what is the ohm or resistance of your coil?

Do you know Ohm's Law, or know how to use an Ohm's Law Calculator? Explain it to the Vape Noob: Ohm's Law Calculations for a Mechanical Mod

Never use a coil that will draw more current from the battery than it has to give. Never use a battery that can not safely supply the amps required to fire a coil.


Mooch's Recommended 18650-size Batteries

Samsung 18650 30Q, 3000 mah 15 amp CDR

*
Sony 18659VTC6 3000mAh 15 amp CDR

*


LG 18650HG2 3000mah 20 amp CDR

Sony 18650VTC5, 2600 mah 20 amp CDR

LG 18650HE4 2500 mah 20 amp CDR

Samsung 18650-25R, 2500 mah 20 amp CDR

Sanyo UR18650 NSX, 2500 mah 20 amp CDR

Sony 18650VTC4, 2100 mah 23 amp CDR

Sony 18650VTC5A, 2500 mah 25 amp CDR

Samsung 18650-24S, 2500 mah 25 amp CDR

Molicel 18650-P26A, 2600 mah 25 amp CDR

LG 18650 HD4 2100 mah 25 amp CDR

LG 18650 HD2 2000 mah 25 amp CDR

LG18650HB6 1500mah 30 amp CDR

LG18650HB2 1500mAh 30 amp CDR

LG18650HB4 1500mAh 30 amp CDR

Sony 18650VTC3 1500mAh 30 amp CDR

Samsung 18650-20S 2000mah 30 amp CDR

* Manufacturer's CDR is 15A. The Samsung 30Q datasheet (Section 7.9) mentions operation at 20A. Operation at that level can be done as long as we don’t let the battery get above 75°C, its maximum rated operating temperature. This holds true for the Sony VTC6 battery as well. These are not a high performance “power” cell, designed for high current. They are a high capacity “energy” cell designed for low to moderate power levels and long running time. At higher current levels the voltage sag and power loss in the cell are huge. Do not exceed 20A.
​

 

[TrollDragon]

Ahhh, the magical quest of trying to find a coil build that actually vapes decently on a single cell unregulated...

A simple single wire build is what you need and it all depends on your battery.
A 6/5 wrap of N80 will give you 0.3 ohms, @ 58W (14A) with a freshly charged battery.

If you are looking to get the same performance on an unregulated mod as you would a regulated, you are not going to find it.

 

[FluidExtractor]

A lot depends upon the specifications of the 18650 battery you are using (especially the amp rating) and the resistance of the coil you are trying to fire.

Do you know Ohm's Law, or know how to use an Ohm's Law Calculator? Explain it to the Vape Noob: Ohm's Law Calculations for a Mechanical Mod

Never use a coil that will draw more current from the battery than it has to give. Never use a battery that can not safely supply the amps required to fire a coil.


Mooch's Recommended 18650-size Batteries

Samsung 18650 30Q, 3000 mah 15 amp CDR

*
Sony 18659VTC6 3000mAh 15 amp CDR

*


LG 18650HG2 3000mah 20 amp CDR

Sony 18650VTC5, 2600 mah 20 amp CDR

LG 18650HE4 2500 mah 20 amp CDR

Samsung 18650-25R, 2500 mah 20 amp CDR

Sanyo UR18650 NSX, 2500 mah 20 amp CDR

Sony 18650VTC4, 2100 mah 23 amp CDR

Sony 18650VTC5A, 2500 mah 25 amp CDR

Samsung 18650-24S, 2500 mah 25 amp CDR

Molicel 18650-P26A, 2600 mah 25 amp CDR

LG 18650 HD4 2100 mah 25 amp CDR

LG 18650 HD2 2000 mah 25 amp CDR

LG18650HB6 1500mah 30 amp CDR

LG18650HB2 1500mAh 30 amp CDR

LG18650HB4 1500mAh 30 amp CDR

Sony 18650VTC3 1500mAh 30 amp CDR

Samsung 18650-20S 2000mah 30 amp CDR

* Manufacturer's CDR is 15A. The Samsung 30Q datasheet (Section 7.9) mentions operation at 20A. Operation at that level can be done as long as we don’t let the battery get above 75°C, its maximum rated operating temperature. This holds true for the Sony VTC6 battery as well. These are not a high performance “power” cell, designed for high current. They are a high capacity “energy” cell designed for low to moderate power levels and long running time. At higher current levels the voltage sag and power loss in the cell are huge. Do not exceed 20A.
​

I'm pretty accustomed to Ohm's law and Mooch's battery list. Never used any mech e-cigs so I didn't really have to refer to Ohm's law. I tried VTC5 and LG HG2, same results from both. Can't give you the exact resistance od my coils at the moment but it's a dual coil with around 0.25 ohms.

Ahhh, the magical quest of trying to find a coil build that actually vapes decently on a single cell unregulated...

A simple single wire build is what you need and it all depends on your battery.
A 6/5 wrap of N80 will give you 0.3 ohms, @ 58W (14A) with a freshly charged battery.

If you are looking to get the same performance on an unregulated mod as you would a regulated, you are not going to find it.

-

I actually haven't thought about using simpler coils. I have a dual build with some more complex coils at around 0.25 ohms. Another question. My current coils heat up fine if I bypass the mosfet and the switch. Is that right? Is that still a matter of coils or is there something wrong with the MOSFET?

 

[Baditude]

I'm pretty accustomed to Ohm's law and Mooch's battery list. Never used any mech e-cigs so I didn't really have to refer to Ohm's law. I tried VTC5 and LG HG2, same results from both. Can't give you the exact resistance od my coils at the moment but it's a dual coil with around 0.25 ohms.

I always have to ask because its extremely important. Each coil is 0.25 ohm? Or both coils together are measuring out at 0.25 ohm?

0.25 ohm has a 16.8 amp draw.
LG HG2 has a CDR of 20 amps.
Sony VTC5 has a CDR of 25 amps.
Taking for granted that both batteries are authentic and not very old, either should be able to fire 0.25 ohm safely.

However, if each coil is 0.25, total resistance will be halved for a total resistance of about 0.125 ohm. That would be a 35 amp draw which is way over both batteries' amp limit.

 

[gandymarsh]

It could be the mosfet. Did you buy it from ebay? Ebay sellers sometimes sell mosfets that don't work correctly. They are also very sensitive to static electricity and heat. Overheating from soldering can destroy them.

 

[FluidExtractor]

I always have to ask because its extremely important. Each coil is 0.25 ohm? Or both coils together are measuring out at 0.25 ohm?

0.25 ohm has a 16.8 amp draw.
LG HG2 has a CDR of 20 amps.
Sony VTC5 has a CDR of 25 amps.
Taking for granted that both batteries are authentic and not very old, either should be able to fire 0.25 ohm safely.

However, if each coil is 0.25, total resistance will be halved for a total resistance of about 0.125 ohm. That would be a 35 amp draw which is way over both batteries' amp limit.

0.25 for both coils combined
Again, not sure about the exact resistance but it's pretty close to 0.25.
Batteries come from a reputable source so they're most likely authentic.

It could be the mosfet. Did you buy it from ebay? Ebay sellers sometimes sell mosfets that don't work correctly. They are also very sensitive to static electricity and heat. Overheating from soldering can destroy

I might have just overheated the mosfet. There is not much room for wiring so my soldering iron might have gotten to close to the mosfet.
The box is Asmodus Spruzza if you're curious. It's a squonk so only 1/3 of the enclousure is available for wiring, especially with a voltmeter in there. I'll try different coils and if that doesn't work, I'll order a new mosfet.

 

[TrollDragon]

I actually haven't thought about using simpler coils. I have a dual build with some more complex coils at around 0.25 ohms. Another question. My current coils heat up fine if I bypass the mosfet and the switch. Is that right? Is that still a matter of coils or is there something wrong with the MOSFET?

Sounds like the MOSFET for sure, if you have the room then a great replacement would be one of Big Al's Mods iSwitch boards. It's a small board that will give you a 5 click on/off, reverse polarity protection and a few other features. Designed for single cell and can drive up to a 40 amp load.

His web site is down at the moment to implement new store software.

 

[sonicbomb]

not sure about the exact resistance but it's pretty close to 0.25

A meter to check the resistance of your coils is vital if you are using an unregulated device.

 

[BrotherBob]

I might have just overheated the mosfet.

Welcome and glad you joined.
Great questions, might like to ask in:
Battery Mods

 

[FluidExtractor]

A meter to check the resistance of your coils is vital if you are using an unregulated device.

I have one, it's just that I wasn't at home while writing that post so I couldn't check the resistance.