V.v Subohm box mod

[andy105]

Looking for some guidance on my first box mod as far as a start im lost(new with limited electronics knowledge) . Im having a hard time hunting down a regulator assuming a 10 amp board will limit sub ohms, a new vv mod made in the philippines claims they are using a ti regulators capable of 40 amps  i was pointed in the direction of an evercool box mod but am still looking for other input if you could help it would be greatly appreciated 

[Breaktru]

Your thinking of 40 amps is way overboard. Using the 10A / 50W PTR08100w regulator will give you way more than you will ever need. Typically we vape at 2 - 2.5 amps for a standard atty resistance. 3, 4 or 5 amps for power vaping.
There is some info here: PTR08100w mod
or use the OKR-T/10 it has the same spec's but does not need capacitors. OKR shematic

Get yourself some good batteries and don't use cheap ones. The good batteries are mentioned several times in this forum

[Xx Smoke xX]

if the 40 amps is overboard, on mechanicals why do people by the 30amp rating 18650 batteries like the MNKE and the Sony and Efest etc. When doing sub ohm's?

My understanding and I may be wrong (wouldnt be the first time) is that when using a .5 ohm resistance if you vape that at 4.2 volts you are pulling 8.4amps but if you drop any lower that .5 ohms you are pulling more than 10amps.

Is that not a concern with the way these circuits work?

[CraigHB]

Yes, it's a concern.  Overloading a Li-Ion battery is something you want to avoid.  They can be quite hazardous when abused. 

Selecting a 30Amp battery is not solely motivated by a desire to actually draw 30 Amps.  The advantage with a higher drain battery is better power delivery resulting in less voltage sag at the atomizer.  For a mechanical mod with no regulator, it can make a difference in atomizer performance.  Also, people need a battery that can handle the pulse method to insulate coils from metal wicks.  This requires a very high drain initially on the battery until the coil is fully isolated.

With any atomizer, there's at least another tenth of an Ohm resistance for the battery internally and for the connection and contacts in the mod.  It can actually vary quite a bit for a mechanical depending on the quality of the mod.  A cheap one may introduce several tenths of an Ohm in the circuit.  In that case, the battery may be actually seeing .7 or .8 Ohms with a 1/2 Ohm atomizer resulting in a considerably lower current draw.

I've seen reports of people using atomizers with only a couple tenths of an Ohm resistance.  The power consumption in that case is extremely high.  I can't see much practicality at all in vaping with that much power.   It seems like more of a novelty to me than anything else.

[Breaktru]

Well said Craig. Thank you

[zeus17]

Yes, it's a concern.  Overloading a Li-Ion battery is something you want to avoid.  They can be quite hazardous when abused. 

Selecting a 30Amp battery is not solely motivated by a desire to actually draw 30 Amps.  The advantage with a higher drain battery is better power delivery resulting in less voltage sag at the atomizer.  For a mechanical mod with no regulator, it can make a difference in atomizer performance.  Also, people need a battery that can handle the pulse method to insulate coils from metal wicks.  This requires a very high drain initially on the battery until the coil is fully isolated.

With any atomizer, there's at least another tenth of an Ohm resistance for the battery internally and for the connection and contacts in the mod.  It can actually vary quite a bit for a mechanical depending on the quality of the mod.  A cheap one may introduce several tenths of an Ohm in the circuit.  In that case, the battery may be actually seeing .7 or .8 Ohms with a 1/2 Ohm atomizer resulting in a considerably lower current draw.

I've seen reports of people using atomizers with only a couple tenths of an Ohm resistance.  The power consumption in that case is extremely high.  I can't see much practicality at all in vaping with that much power.   It seems like more of a novelty to me than anything else.

so in such a case,

if i may,in laymans terms.

this is where things like voltage drop matter?is that it?

as your example,

if i vaped on a poor quality mod,and built a 0.4 ohm coil,powered by a 30amp battery vs a close to no voltage drop mod with the same batts and coil,in this case i should have better results on the latter?
and on a vv it does not really matter that much because it will be restricted to the 10amp (using the OP's example) max regardless if i am using a 20amp or a 30amp.,only difference is i will not be stressing my 30amp batteries?

[CraigHB]

The cavernous difference between a mech mod and VV mod is that with a regulated mod the voltage settng is the voltage at the atomizer connector when the atomizer is powered.  The same losses occur for things like battery internal resistance and battery contacts, but the regulator compensates for that.

With a mech mod, you're setting up a division in voltage between the total resistance of the circuit and the resistance of the atomizer.  It's a classic voltage divider circuit.

To make an example, lets do the following;

You are using a high drain battery with 25 mOhms internal resistance. 

You have a really good mech mod that only introduces 75 mOhms resistance through connections and contacts.

Let's use an atomizer with 300 mOhms.

We'll calculate current flow with median battery voltage of 3.8V.  Total resistance is 400 mOhms so current flow is 9.5 Amps.  Power at the atomizer is current squared times resistance which is 36 Watts.

Lets do the same thing with a regulated mod.  In that case, voltage is set at 3.8V and atomizer resistance is also 300 mOhms.  Current flow is 3.8V divided by 300 mOhms which is 12.7 Amps.  Power at the atomizer is 48 Watts.  Pretty big difference.

[zeus17]

The cavernous difference between a mech mod and VV mod is that with a regulated mod the voltage settng is the voltage at the atomizer connector when the atomizer is powered.  The same losses occur for things like battery internal resistance and battery contacts, but the regulator compensates for that.

With a mech mod, you're setting up a division in voltage between the total resistance of the circuit and the resistance of the atomizer.  It's a classic voltage divider circuit.

To make an example, lets do the following;

You are using a high drain battery with 25 mOhms internal resistance. 

You have a really good mech mod that only introduces 75 mOhms resistance through connections and contacts.

Let's use an atomizer with 300 mOhms.

We'll calculate current flow with median battery voltage of 3.8V.  Total resistance is 400 mOhms so current flow is 9.5 Amps.  Power at the atomizer is current squared times resistance which is 36 Watts.

Lets do the same thing with a regulated mod.  In that case, voltage is set at 3.8V and atomizer resistance is also 300 mOhms.  Current flow is 3.8V divided by 300 mOhms which is 12.7 Amps.  Power at the atomizer is 48 Watts.  Pretty big difference.

so in such a case a regualted mod delivers more power compared to a mech?
i guess tghe next question is what vv mod,would be best,cause i think most v vmods comercially out today are limited below 5amps?i maybe wrong thou.

if such is the case making my own mod,would be best done?or so is OP's intent?

[CraigHB]

so in such a case a regualted mod delivers more power compared to a mech?

Well, the thing is a mech can deliver higher amperage since it's not limited by what electronics can handle.  In terms of raw power, a battery like the Sony US18650VTC3 can output 30 Amps times a nominal 3.7V which is over 100 Watts. 

The difference between a regulated and unregulated mod is that a regulator provides a constant higher voltage so it's possible to get higher power output without using an extremely low resistance atomizer.  You can simply dial things into your preference.  The only way to adjust power output with a mech is to adjust atomizer resistance.  To get those high power levels, you need an extremely low resistance.

Keep in mind, it's not just about amperage.  The performance you get out of your atomizer is about power and that depends on current *and* voltage.  Resistance is critical because it determines the amperage you get with a particular voltage.

i guess tghe next question is what vv mod,would be best,cause i think most v vmods comercially out today are limited below 5amps?i maybe wrong thou.  if such is the case making my own mod,would be best done?or so is OP's intent?

Yes, most regulated mods you buy off the shelf are not able to provide output currents over 5 Amps.  It's a limitation of the electronics design they use.  The DNA20 and can do 6 Amps at its minimal voltage and the DNA30 will probably be able to do 8A at its minimal voltage. 

A design based on the OKR-T/10 can output 10 Amps, but you can find off the shelf buck converters with maximal current outputs even higher than that.  The OKR can put out as much as 50 Watts which is a pretty extreme amount of power to vape with.  Though people running ultra low resistance atomizers with mechs are getting close to power levels like that. 

I just started working on a 40 Watt buck-boost converter design for my own mods.  Buck-boost allows a wider voltage range when using a single cell.  I'm going for a range of 2.7V to 8.0V with a target current output of 15 Amps at 2.7V.  I'm basing it on the Linear LTC3785 controller. 

I've had my eye on that LTC3785 controller for a couple years and never tried it due to PCB space issues.  It uses four MOSFETs compared to two for a booster.  Vishay has recently released a new line of smaller power MOSFETs that allows me to fit it now, they make really good MOSFETs.

The new converter is only on paper so far.  I have to build one and bench test it to see if I can get those kind of outputs out of the design.  It would be able to handle an atomizer with resistance as low as .18 Ohms.

[Breaktru]

Can't wait to see your next marvel mod Craig 
I always wondered why people would risk a battery catastrophe with sub ohm coils when we can dial our extreme output with VV converters using higher safer resistance coils.

[zeus17]

Can't wait to see your next marvel mod Craig 
I always wondered why people would risk a battery catastrophe with sub ohm coils when we can dial our extreme output with VV converters using higher safer resistance coils.

for once i think i can answer this

a couple of  things lack of knowledge ,availability and form factor..

most of us specially the more common vapers,don't know this facts..such facts ar enot available on the mainstream vaping community.and the popularity of sub ohm+mech is getting outrageous to a point that every one tries them,gets satisfied with very little knowledge.

availability,as far as i know there are limited vv mods out there that can go head to head with the popular sub ohm+mech,very limited..only ones i know are the altitude box,and the GI2,\
then again there is the cost of such and availability,like in my country,,,
its easier to grab a mech compared to a vv mod,
a vamo mod here and a zmax are pretty much close to unicorns,i have not met anyone in huge vapemeets that holds a vamo

yes there are great tutorials on this site to make such powerful mods,but then again not everybody can build them...

form factor,well most of us still loves the old space ___ design...
thou i personally would love to hold a box mod like a gi2,atb or altitude box,but that is not for every one...

[CraigHB]

Electrically speaking, it's always better to use higher voltage and lower currents.  I think people are big on these ultra-low resistance atomizers because it allows you to get big power outputs out of a mechanical.  Though there really aren't many advanced mods that can put out power like that either.  In any case, it's not something to screw around with if you have no clue what you're doing.  People have hurt themselves from overloading batteries before.

Been working on this new converter I want to do.  It's tough because it has to be stabilized for both buck and boost where it's much easier to tune for one or the other.  The high power outputs make it less stable so it's tricky to do.  Been running simulations like crazy and looks like I have a compensation network worked out that's going to do the job.  Have to build it to see for sure.

[zeus17]

Electrically speaking, it's always better to use higher voltage and lower currents.  I think people are big on these ultra-low resistance atomizers because it allows you to get big power outputs out of a mechanical.  Though there really aren't many advanced mods that can put out power like that either.  In any case, it's not something to screw around with if you have no clue what you're doing.  People have hurt themselves from overloading batteries before.

Been working on this new converter I want to do.  It's tough because it has to be stabilized for both buck and boost where it's much easier to tune for one or the other.  The high power outputs make it less stable so it's tricky to do.  Been running simulations like crazy and looks like I have a compensation network worked out that's going to do the job.  Have to build it to see for sure.

thats absolutely true,


i am much intrigued on these project of yours ,hopefully its something that will be made available for everyone hahahahhaha
but if not still cool thou!

[horton]

Perhaps I'm heading off topic here but I just had to comment about the big batteries, and the big numbers that are being thrown around so nonchalantly on many forums.  I do not think that most of the folks who are trying to obtain vaping nirvana (for lack of a better term) realize they might be holding a bomb in their hands.  I cringe when I think that just one disaster happening where someone blows off part of their lip or worse.  An event like that could really cause problems for the vaping community.  I can just see the govt. waiting in the wings to swoop down and "protect" the innocents out there from themselves. 
Sorry to rant, but it has been a big concern to me since I've been reading about  sub ohm vaping and mech mods.  Ok..... I'm done and hope I have not made a fool of myself.

[Xx Smoke xX]

If I understand correctly 

I have a mech, and run a .67 ohm coil on it with a 30amp high drain battery. I like it because it gives massive clouds full of flavor.

From reading this though, with making our own mods that put out more than 4 amps basically we can achieve the same result(massive clouds full of flavor) but safer. By using our own VV mod and like a 2ohm coil at 6 volt, but pushing 10amps to it?

sorry if the answer is obvious but I think that is what was being said, Is that right? 

[zeus17]

Perhaps I'm heading off topic here but I just had to comment about the big batteries, and the big numbers that are being thrown around so nonchalantly on many forums.  I do not think that most of the folks who are trying to obtain vaping nirvana (for lack of a better term) realize they might be holding a bomb in their hands.  I cringe when I think that just one disaster happening where someone blows off part of their lip or worse.  An event like that could really cause problems for the vaping community.  I can just see the govt. waiting in the wings to swoop down and "protect" the innocents out there from themselves. 
Sorry to rant, but it has been a big concern to me since I've been reading about  sub ohm vaping and mech mods.  Ok..... I'm done and hope I have not made a fool of myself.

your concern sir is valid,specially right now that fda is breathing down the vaping communitys neck right now,and one blowing battery on someone's face,will surely get us regulated faster than you can say idontwnatanothercig.

all i takes is one noob,trying a octacoil build on a lausy laptop battery...

yes the crazy low ohms + mech is really all there is on majority of forums out there..
i am actually surprised that close to no one here does it,aside from me...
i don't really know my math,but i know on how low i can go on a set of my batteries.

[CraigHB]

e-Cig battery fires have happened already numerous times.  I have seen many reports on the e-cig forums I frequent.  Most happen on the charger, but a few unlucky souls have had mods blow up in their face.  I also share the concern about the government stepping in to protect consumers.  For products purchased over the counter like the eGo it's more of a concern than people using mods with incorrect batteries.

Lots of people do stupid things with consumer products that result in physical injury.  If someone insists on doing something unsafe with something not intended for the purpose, there's nothing anyone can do to stop them.  Governments usually only step in on safety issues when over the counter products are unsafe for their intended purpose.

I think people tend to think of Li-Ion batteries the same as the ones you buy at the grocery.  They don't realize they can be volatile.  If you are using a cell within its design limits then there is no concern for safety other than the usual considerations.  It doesn't really matter whether you are using high currents or low currents.  The hazard comes when using a cell outside its design limits.  It doesn't matter whether that's 1 Amp or 30 Amps.

[horton]

My intent was not to offend anyone here or anywhere for that matter.   I'm sorry and apologize to those who took umbrage at my comments.  I should have made sure my brain was engaged before putting tongue in motion. (think that is part of an old quote, but highly accurate for me.....lol) 
I simply was trying to state my concerns about the dangers of using the LiOn batts, low ohm devices, etc., without knowing how dangerous they can be.  I certainly don't feel that is an issue on this forum with the high level of knowledge members have here.     
PV's are becoming so popular of late and I don't want to see any of us, no matter what our style of vaping may be,  have our options limited by a serious accident occurring.  Maybe I'm just a worrywort???
Again, my apologies for my comments not being  apropos to the subject matter at hand. 

[Breaktru]

I don't think that you offended anyone horton. You are just expressing a genuine concern for the well being of fellow vapers. I share your concerns as well.
I have tried sub ohms myself just to see with all the fuss was about. I am quite satisfied with my vapor production using 1.5 ohm and 2.0 ohm setups on a VV mod of my own making. Super clouds for me using the PTR08100w, OKR-T/10 and even my freak PTN04050 which is capable of 30 plus watts. With good batteries and a proper coil/wick build, it is possible.

[horton]

Thanks, Breaktru..... I appreciate your kind words.   
I have not tried the sub ohms, not having a mech mod, but have been fiddling around with the micro coils (or maybe better said, smaller diameter coils) a little and so far like them.  I'm in the same ohm range as you so I use  them on a VV mod as well.  Very happy with the amount of vapor I'm getting and the TH hit is nice and mild.   I don't know if it's my imagination or not, but they do seem to heat up much faster.   
It's so enjoyable to experiment in order to "tune in" the right vape for one's own vaping style.   So glad I bought big spools of wire!! 
   

[DjKiDD]

...even my freak PTN04050 which is capable of 30 plus watts...

PTN04050's Datasheet says it is rated for up to only 12W... Did you just push it extra hard? 30W pulsed?

[Breaktru]

Like I said it's a freak. I used a 20C Li-Po battery and heavy duty short wire runs. NOT pulsed, constant

[CraigHB]

It's the way boosters work they can only add to output voltage not subract from it.  It will hit its maximum switch current and stop boosting there, but you can push it beyond that.  You'll get  some regulation error, voltage will drop a bit, but it will still be greater than no boost.

[Breaktru]

The datasheet shows a max amperage of 2.4 amps but I have exceeded the spec. In the attached photo it shows 4.67A but I went higher. I don't recall exactly but it may have been around 6A.

[CraigHB]

Switch current is probably going to be about 7 amps there so it is a bit surprising it's able to put out those numbers.  Normally, the booster would hit the current limit on the switch sooner than that.  Should be about 5 amps, but who knows.  I looked and it doesn't say anywhere in the data sheet.

[Visus]

Thats great news im using the 8060 rated @6a and I already know it is underrated.  The 08100 10a is very underrated, some people use it at 60 watts for  robot builds so I hope the 8060 is also underrated.   Ill never use more than 5a but to have more gas pedal  is nice lol...

I will be using the 4050 with a lipo battery so hopefully mine will also be a freak.. Jury is still out on build form so idk it may be a 20c flat cell or 15c round, I will post results ..

[zeus17]

My intent was not to offend anyone here or anywhere for that matter.   I'm sorry and apologize to those who took umbrage at my comments.  I should have made sure my brain was engaged before putting tongue in motion. (think that is part of an old quote, but highly accurate for me.....lol) 
I simply was trying to state my concerns about the dangers of using the LiOn batts, low ohm devices, etc., without knowing how dangerous they can be.  I certainly don't feel that is an issue on this forum with the high level of knowledge members have here.     
PV's are becoming so popular of late and I don't want to see any of us, no matter what our style of vaping may be,  have our options limited by a serious accident occurring.  Maybe I'm just a worrywort???
Again, my apologies for my comments not being  apropos to the subject matter at hand.

i think that no one was offended sir,and i guess every one in these forums are genuinely concerned on everyone's safety.
i for one do agree with your sentiments