Unregulated help!

[xzackt321]

Hey guys, about 6 months ago I built my first unregulated box mod in a hammonds / 2-18650s. After the box was built it didnt seem to hit as hard as I hoped and was told an unregulated box mod hits. So I jumped on reddit and started asking questions and turns out I wasnt using the correct mosfet. One guy suggested the IRLB3034, so I changed out the mosfet and the box still hits like my wifes eleaf mini set on 35w.. in other words.. it doesnt.. can anyone help me fix this or diagnose where I went wrong to correct the issue. Not sure if I used the wrong fuses, gauge wire, or if the mosfet is still dampening the power?
Box specs,
2-18650 batteries
2-Resettable Fuse - PPTC 77 ACT TEMP. 15A HOLD (1 Piece)
1-IRLB3034 Mosfet
16g wire power
18g wire grounds
510 connector
2 post push button switch
If I missed anything I apologize im doing my best to recall what I used for this mod.
Thank you guys for your help and input.

 

[Sonar505]

You did not mention what size resistor you used on the mosfet? But anyway when I have had this happen to me when building a new box mod. I have tried checking every other part but it seems to always come back to the mosfet. The one you installed is the correct one and is one I use all the time. But I have installed brand new ones and had them perform the way you describe. And after replacing them again it fires correctly. So something in the mosfet seems to be not working correctly the only other thing it might be is double check all your solder joints should all be shiny and smooth.

 

[xzackt321]

Thank you for the suggestion. I have 4 more so I will change that out in the morning and see if that fixes the issue..
As far as the resistor on the mosfet.

1- 25EP51415K0 15K Ohm Resistors,
1/4 W, 5%

 

[Sonar505]

yep that is the one i also use. If you have a multimeter do a google search for how to test a mosfet. There is a guy that has a video with a simple method of running a test on your mosfet I was able to check numerous ones to see if they varied to much from his simple test. And save myself from having to install them to check It is not full proof but does help.

 

[DIY FancyLights]

I've also heard of cases where bad solder joints have messed up builds, specially on the high current wire.

One person had a bad joint between the MODFET & the BatteryMinus which was acting like a resistor. That had a side effect of preventing the MOSFET from turning on totally since they are controlled by the difference in voltage between their Gate and the Source pins. The moment current started flowing, the voltage on the Source pin which should have been ground started climbing and that lowered how much the MOSFET could turn on.

Remember that the amount of current through the coil will also be the same as the current from the BatteryMinus to the MOSFET, so you mentioning 18 awg wire on the ground seems odd. In electronics, grounding is important and is at least the same size as the power and often is larger and/or multiple wires to prevent any voltage difference between true ground and the ground seen by parts/boards.

 

[kim leith]

yep that is the one i also use. If you have a multimeter do a google search for how to test a mosfet. There is a guy that has a video with a simple method of running a test on your mosfet I was able to check numerous ones to see if they varied to much from his simple test. And save myself from having to install them to check It is not full proof but does help.

I asked this in another thread.
If a dual 18650 paralel wired box with potentiometer be able to push 6 volts when set at 100%?
Also is it a safety issue?

Thanks

 

[DIY FancyLights]

I asked this in another thread.
If a dual 18650 paralel wired box with potentiometer be able to push 6 volts when set at 100%?
Also is it a safety issue?

Thanks

If this is unregulated, what is the pot for? Also, dual 18650 in parallel only increases the current available, not the voltage, so with fresh batteries 4.2V is the max you'll see.

 

[HondaDavidson]

Are you sure it's the box and not the Coil build????? You have to build differently for unregulated vs regulated.... I use a hotter faster coil unregulated than I would for the same vape with a regulated mod.

On the potentiometer thing, the answer depends on which pot you use. In most cases the pots used in a mod are variable resistors. They limit output to a set level, typically those levels are lower than max battery voltage. So a series mod can output the same 6v from charge to charge. Provided you change the batteries before they drop below a little over 3 volts.

 

[DIY FancyLights]

Are you sure it's the box and not the Coil build????? You have to build differently for unregulated vs regulated.... I use a hotter faster coil unregulated than I would for the same vape with a regulated mod.

On the potentiometer thing, the answer depends on which pot you use. In most cases the pots used in a mod are variable resistors. They limit output to a set level, typically those levels are lower than max battery voltage. So a series mod can output the same 6v from charge to charge. Provided you change the batteries before they drop below a little over 3 volts.

My concerns are related to the fact a pot in connection an unregulated build is not normally practical and I have to guess on how you are thinking it would be wired in and used/

1. The resistor on a MOSFET build is there just to make sure it turns off , not to adjust the power.
2. Trying to use a pot to control a MOSFET means the MOSFET ends up being used partially on, so you risk it overheating to get desired current to your coil
3. A pot used directly on the high currently lines must be a very large high current one
4. A pot + PWM is technically the simplest regulated mod, not unregulated.

 

[Sonar505]

I asked this in another thread.
If a dual 18650 paralel wired box with potentiometer be able to push 6 volts when set at 100%?
Also is it a safety issue?

Thanks

Ok I have seen this same question quite a few times over the years. Eventually people provide the answer so here goes. A pot no matter what resistance has to be paired with a regulator board in order to be able to adjust the voltage to the level desired. Dependent on the input voltage required by the regulator board is how you determine whether you can use a single or dual parallel battery configuration which inputs 4.2v or need a series battery configuration which will input 8.4v. Then the pot (usually with an added resistor) will allow you to adjust the output voltage between 2 set points. Typically between 3.5 and 6 volts. Sorry but a pot alone connected to your batteries will not work the way you think.

 

[Sonar505]

@xzackt321 Can not make out your rating badge. And are you currently serving? It's good to see a fellow squid.

 

[kim leith]

Ok I have seen this same question quite a few times over the years. Eventually people provide the answer so here goes. A pot no matter what resistance has to be paired with a regulator board in order to be able to adjust the voltage to the level desired. Dependent on the input voltage required by the regulator board is how you determine whether you can use a single or dual parallel battery configuration which inputs 4.2v or need a series battery configuration which will input 8.4v. Then the pot (usually with an added resistor) will allow you to adjust the output voltage between 2 set points. Typically between 3.5 and 6 volts. Sorry but a pot alone connected to your batteries will not work the way you think.

Thanks for the input.
Sonar505 answered the question I formed in my head, which was by using a pot using %'s I could cut back the 8.4v from a series to get the 6v to 7v range to appease my taste. 8.4 of the straight series set up or "mechanical" like my N.C.
Just wanted a little bit of play area, knowing the set up is not a "true mech"

Anyone wish to share their series mod w/o a pot build set ups?? Looking for a hard hitting vape like with a single batt mech in a box.

Thanks for humoring a "newbie" to the series box mod side of vaping.

 

[kim leith]

Are you sure it's the box and not the Coil build????? You have to build differently for unregulated vs regulated.... I use a hotter faster coil unregulated than I would for the same vape with a regulated mod.

On the potentiometer thing, the answer depends on which pot you use. In most cases the pots used in a mod are variable resistors. They limit output to a set level, typically those levels are lower than max battery voltage. So a series mod can output the same 6v from charge to charge. Provided you change the batteries before they drop below a little over 3 volts.

Honda D;

What coil configurations do you like for a dual 18650 series build?

 

[HondaDavidson]

Honda D;

What coil configurations do you like for a dual 18650 series build?

I dont.. I'm a sub 20 watts vaper. I suppose if I were to go series I'd build in the 2 to 3 ohm range.

I have a 75 watt mod that rarly runs at more than 3-3.5volts.

I'd be more likely to rewire the mod as a parallel.

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