Roughstack 7.4v + ST 3.0 Dual ; Cart gets HOT after a few drags

[phishfood]

Got the RS 7.4v v2 today

Filled up a SmokTech 3.0 dualie with the included USA 24mg mix and it was so harsh I was like holy crap I need some 3.0v batteries ASAP.

Decided to try a juice I liked and filled up a fresh cart with Halo Menthol Ice, and used my low nic bottle (7mg) just so if I got hooked on the RS I wouldn't over-vape nic.

Now the Halo tastes great in the dualie at 7.4, not harsh

But man three drags and the cart is so hot I have to let it sit to avoid burning my lips.

 

[dale1962]

Need to get you some drip tips....but with 3.0 shouldn't be that hot I wouldn't think,like said before I have used 2.0 at 7.4v and is really to low at that voltage would have thought 3.0 would be good.Maybe you should check the ohms on that carto.

 

[phishfood]

Just checked both the filled carts, fluctuates 3.1-3.4 ohm

 

[phishfood]

Of course when the USA mix is on there I can hit the button about 1/2 a second two or three times during the drag without it being overwhelming

With the Halo mix I can take a a good long hold the button down three seconds and it's totally smooth

 

[JimmyJet]

Well, just looking at the math...

3.7V at 2.0 ohms = 6.8 watts

That is a very common combination with vapers.

7.4V at 3.0 ohms = 18.2 watts

Needless to say, 18.2 watts is a lot of heat. Different liquids vape differently at higher temps.

Just an observation.

JJ

 

[dale1962]

Had this conversation before and I don't know much about electrical stuff but I vape the 1.6 at 5-6v all the time perfect combo for me.Have tried the 2.0 ones at 7.4 too hot.Now haven't tried the 2.5 or 3.0 yet at 7.4v but will be picking some up next trip to MV.Has anybody else besides OP tried these yet at 7.4 and what is your opinion?I always thought since these are dual coils the 1.6 acted like 3.2ohm single coil and 2.0 like 4.0 and so forth.

 

[JimmyJet]

Yeah hopefully an electrical engineer will chime in here. I only know that volts squared divided by ohms equals watts. There is a nice calculator here...

Ohm's Law / Watt's Law Calculator

In vaping we often talk about volts because it is convenient. But ultimately we are talking about heat. Wattage is a measurement of heat.

Yes maybe the math is different though with the dual-coils.

 

[dale1962]

JJ hope you didn't take me wrong I just don't know.All I do know is that the 1.6 DC's are to weak for me on lets say epower at 3.7v and on MaxiRS at 6v perfect but here again like big hit.I got a couple of 18350's just laying around so I'm going to get me some of those 2.5-3.0 DC's and slap them in my Goldrush and see how they fly.

 

[Killjoy1]

Yes maybe the math is different though with the dual-coils.

I'm definitely no electrical engineer, but from what I understand since the dual coils are wired in parallel the total wattage delivered is split between the coils, so using your example above (7.4V at 3.0 ohms = 18.2 watts) each individual coil is getting 9.1 watts. That's still a pretty good amount of heat for a single coil and with two of them that close together it certainly would get the carto quite warm.
It's also a noticeably higher wattage than, for example, 5 volts on 1.6 ohms (15.6 watts), which puts 7.8 watts through each coil if my understanding is correct. I'm inclined to believe that assumption, too, simply because that 15.6 watts doesn't burn my juice beyond recognition like I would expect ;-)

 

[JimmyJet]

JJ hope you didn't take me wrong I just don't know.All I do know is that the 1.6 DC's are to weak for me on lets say epower at 3.7v and on MaxiRS at 6v perfect but here again like big hit.I got a couple of 18350's just laying around so I'm going to get me some of those 2.5-3.0 DC's and slap them in my Goldrush and see how they fly.

Yeah, it's cool Dale. Just having fun learning a little about electrical stuff. So far I have not tried any HV vaping, but I would like to. If we have a meetup sometime in the future maybe you could give me a demo.

I did buy the 4.8V batts from MV but all my cartos are 1.7 or lower. The vape bordered on burnt with that combo. Might be the liquid I was using.

 

[six]

I did buy the 4.8V batts from MV but all my cartos are 1.7 or lower. The vape bordered on burnt with that combo. Might be the liquid I was using.

I can agree with your assessment of that for sure. Some juices can take it and some can't. -- What I like with the ni-mh batts is either the standard dual coils with just about any juice in them, or a 2.0 ohm boge with 100% VG. 1.8, 1.7 ohm and lower single coils are just too hot with the 4.8v batts and most juices taste scorched. I only have a couple of juices that can take it in a single coil (AVE PG-Hype comes to mind, and so does madvapes TopVapor Spearmint), but the cartos need to be kept really wet and so it doesn't make a lot of sense to vape that way - may as well just drip an atty for how wet a single coil 1.7 or 1.8 ohm carto needs to be kept with the ni-mh batts.

 

[MASTER0FDAMPF]

Other than a drip tip I would recommend an extender to protect your batts. My stack gets really hot with a 2.5@6v and the body would get warm enough to feel it on the bottom of the stack. Im not even pushing it as hot as you are (it seems) but I do chain vape alot though.

 

[phishfood]

For a test I went out and got a couple standard 3v liion batteries.

They now burn too cold. Metered batteries, 3.2v each.

Fresh the 3.7v batteries are really about 4.2 ... the carts are hot and when I measure batteries after they get down to where the vape is good they show about 3.8.

Not sure, might just have to chuck em. Too hot at 8.4, too cold at 6.4