Do you prefer a LR or SR carto?

[John D in CT]

i have only had my provari mini for 2 days but i have tried a LR carto and i really don't see the need for it, maybe someone can fill me in? i use standard 3ohm boge cartomizers as well and adjust the voltage to exactly what i like.

No, there is no need for low resistance when you can simply increase the voltage and use a higher-resistance carto to arrive at the same watts, and with fewer amps.

Frick, who deserves a medal, explained it incredibly well.

This thread that I might have already linked to is a must-read IMO:

http://www.e-cigarette-forum.com/fo...ined-detail-single-dual-coil-atty-cartos.html

Number of coils is all-too-often left out of discussions of resistance, and was a source of much confusion for me, and I think for others as well. It was only recently that I realized that all other things equal, each coil of a dual coil will get half the watts (heat) of a single coil, which obviously has a huge impact on the vape.

So: not only are watts equal to volts x volts / resistance; you have to divide by two for dual coils. The voltage and resistance that will put 8-10 watts through a single coil would put 4-5 through each of the coils of a dual coil that's rated at the same resistance. That is because a 1.5 ohm dual coil would use 2 - 3ohm coils wired in parallel to yield a total of 1.5 ohms, but each coil still has to be fed current as if it was the 3.0 coil that it is in order to get it as warm as the same amount of watts going to a single coil.

 

[ebbrey]

This might get complicated.

In your examples:

4.7V * 4.7V / 2.2 ohms = 10.04 watts.

Amperage draw would be 2.21 amps on a mechanical mod (no boost circuit).

5.5V * 5.5V / 3 ohms = 10.08 watts

Amperage draw = 1.83 amps, again on a strictly mechanical mod (disregarding the fact that we don't have 5.5V batteries).

The higher-resistance coil draws less amperage to provide the same wattage at the coil. We should get significantly better battery life using a higher-resistance coil, all else being equal.

BUT, the boost circuit changes all that, because the unit is drawing additional amperage from the battery to reach the set voltage.

So, we have to substitute the battery voltage to amperage calculations, not the set voltage.

Except we can't really do that, because battery voltage is variable from 4.2V right off the charger, to ~3.4 or 3.3V at cutoff, and the boost circuit isn't 100% efficient.

If we use a "happy average" of 3.7V in the calculations, we get:

2.2 ohm coil at 4.7V set voltage will draw 2.71 amps, but we have to factor in boost circuit efficiency. Provape uses a figure of 90-95% efficient, so if we assume 90%, we're drawing 2.71 amps/0.9 = 3.01 amps.

2.2 ohm coil, 4.7 set voltage, 3.01 amp draw.

Second example: 3 ohm coil at 5.5V set voltage will draw 2.71 amps again; after factored for efficiency, 3.01 amps.

So doing the math gives us the same result, regardless of coil resistance.

Despite that fact, with all the math done and considerations taken, I still get better battery life out of a 3 ohm coil than I do a 2 ohm. I can't be sure why, because according to the math, it's impossible, but after owning a Provari for a few months and running a wide variety of coils, it seems it's true.

Read here for more information, under "Why does the ProVari need to use high drain batteries (the full technical answer)?": http://www.provape.com/v/faq.htm

whoaa, thx a million for the in dept explenation

 

[Shortstuff116]

Ok Frick. I thought that your explanation was incredibly accurate and very informative, but I have to admit that my head is still spinning. I must be getting old.

 

[harleydiva]

I want to try the Boge, but I'm a bit confused over the XL and XXL types that are mentioned.

I have a 7ML LavaTank, a 3.5ML LavaTank, a Sub Tank and a Who's Your Daddy tank on the way.

I've been using the 1.7 Ohm Dual Coil and 3.0 Ohm Single Coil pre-punched SmokeTech Cartomizers.

I have a Cartomizer Punch on hand to punch the Boge Cartomizers, if I could only figure out which ones to purchase.

Can someone please post a link where I can obtain the Boge XXL Cartomizers? I'm not concerned if they protrude up past the top of the Tanks that I have.

Thanks for any help.

George

Where did you get the LavaTanks??

 

[WA3PNT]

Volcano eCig in HI. Ordered them when I ordered the LavaTube.

They only carry the SmokTek Cartos.

George

 

[Frick]

Ok Frick. I thought that your explanation was incredibly accurate and very informative, but I have to admit that my head is still spinning. I must be getting old.

I probably should have boiled it down a bit at the end.

In a strictly mechanical mod without a boost converter, using a higher-resistance coil requires less amperage draw from the battery than using a lower-resistance coil to achieve the same wattage at the coil.

You can check the math using Ohm's law by plugging the numbers into any online Ohm's law calculator.

So, using a higher-resistance coil will achieve longer battery life in a mechanical mod.


But, in a mod with a boost converter, we have to use the battery voltage, and not the device's set voltage, in Ohm's law calculations, as outlined in the Provari FAQ.

So it would appear that there is no advantage to using a higher-resistance coil in a boost converter mod. There's also Pulse-width modulation to consider, but that's another matter.

Regardless, I seem to achieve longer battery charge-life with a higher-resistance coil. I'm not sure why.

 

[PocketGroove]

Wow...the things I've learned in the past month of vaping. I'm gonna apply for a mechanical engineering minor.

Since I'm a noob I will chime in with my anti-science, purely experience based observation in regards to LR vs SR on the provari.

LR attys get too damn hot for me.

That is all.

 

[dchest02]

I use Boge 2 ohm cartos at 4.5v, and it is only because I am lazy. I found a perfect setup, and I am perfectly happy with it, so why change now.