How do you safely test below 1 ohm?

[sawlight]

Had this come up in a few other threads. I have a VERY nice Mac tools DMV, made by Fluke, but I honestly don't trust it below a half ohm. Honestly, anything below 1 ohm I quadruple check! But even then it can vary.
This afternoon I built a coil to go on my new Theorum tank. As built, it was right at 1 ohm, on the mod I've gotten everything from .66 to 1.7. It seems to now have settled in at 1.4.
But reading some of the "......... mod blows up!" threads, and cloud comps where they are at .1 ohms. I have to ask, how are they safely and accurately testing this? How are many of you testing some of your builds at .02, or whatever?
Are you using the $10 readers? Are you using a better meter than I have?
I'm sorry, but I just can't wrap my head around one of those $10 meters working better than a $300 Mac/Fluke, that I have issues trusting at that level!
I'm not trying to be mean, not trying to call anyone out, not trying to start a flame war, I'm just really curios what people use, how accurate it really is, and how much faith you really put into it!
For the record, I'm looking into getting a 521 tab, and will most definitely buy one when the funds are free. But even then, I'm not sure how much I'd trust it below 1 ohm.

 

[BillW50]

Well don't waste your time on those $10 meters. They are horrible. And sure, I have bought meters that cost hundreds of dollars. But many of those TC mods have excellent ohm meters for much less. They have to be good at reading resistance or they can't do TC correctly. A DNA200 for example can read as low as 0.001 ohm with the EScribe software.

 

[sawlight]

Yeah, I can't put any faith into the cheap table meters. I agree with the mods, but say you are building for a mech, how do you check it? How are shops testing when they have a cloud comp going on and you can only have a .2 ohm build?
I was also watching Grimm Green one time, he did a build, checked it on a meter, put it on a mod and got another reading. He then tried it on three other mods, two of which were DNA 200's, and every one of them had a different reading, not a huge swing, but enough to cause pause when pushing things.

 

[NGGrant]

That's the atomizer try tightening down the cooil leads it should not jump around like that

 

[sawlight]

That's the atomizer try tightening down the cooil leads it should not jump around like that

I've loosend them, tightened them, torgued them again. Nothing. Like I said, it seems to have settled in at 1.4 now.

 

[BillW50]

I was also watching Grimm Green one time, he did a build, checked it on a meter, put it on a mod and got another reading. He then tried it on three other mods, two of which were DNA 200's, and every one of them had a different reading, not a huge swing, but enough to cause pause when pushing things.

Well for the DNA200, you can calibrate them. Other mods, not so much. I did a test like this last year. But here we go again. None of my DNA200 mods were calibrated. Although the Reuleaux DNA200, Wismec did add 0.003 ohm for internal resistance. HCigar left theirs at 0.000 ohm. This was done with the same coil on all of them. The DNA200 has two ohm readings. First is the mod display readout and the second is from EScribe.

2016 May 8
PUR Heatvape Invader Mini 0.54 ohms
BLU Heatvape Invader Mini 0.55 ohms
YEL Heatvape Invader Mini 0.55 ohms
BLU Heatvape Invader Mini 0.56 ohms
B/W Heatvape Invader Mini 0.55 ohms
Reuleaux RX200 Teal/White 0.57 ohms
Reuleaux RX200 Black 0.57 ohms
Reuleaux DNA200 1 0.57 ohms / 0.569 ohms
Reuleaux DNA200 2 0.55 ohms / 0.563 ohms
HCigar VT133 1 0.55 ohms / 0.569 ohms
HCigar VT133 2 0.56 ohms / 0.550 ohms

 

[TheRussianVaper]

I would recommend to use safe mods, if you are using mech mods, then I strongly recommend spending at least $30 on ohm meter. Dont forget to re-test after dry firing and refitting. I would suggest an Ohm tab, you can dry burn on it and test it at the same time, much safer that way.

 

[sawlight]

I would recommend to use safe mods, if you are using mech mods, then I strongly recommend spending at least $30 on ohm meter. Dont forget to re-test after dry firing and refitting. I would suggest an Ohm tab, you can dry burn on it and test it at the same time, much safer that way.

The point of this thread was how accurate are those tabs? If I don't trust my Fluke meter below .5 ohms, how can I be assured a $30 meter is that much better than a $300 DMV?

 

[TheRussianVaper]

The point of this thread was how accurate are those tabs? If I don't trust my Fluke meter below .5 ohms, how can I be assured a $30 meter is that much better than a $300 DMV?

Sorry I misunderstood. Cant think of anything better than DVM.

 

[Eskie]

The point of this thread was how accurate are those tabs? If I don't trust my Fluke meter below .5 ohms, how can I be assured a $30 meter is that much better than a $300 DMV?

I just ordered one of those, really for the convenience of the build/burn, but I don't intend going below 1 ohm anyway. If you don't trust your Fluke below 0.5 ohm, I would take no comfort in a $30 521 either. Personally, and not knocking a product, but even with a DNA 200 board, I would take your Fluke reading over the mod as the most accurate, and if it tests out at 1 ohm, just accept it and use your wattage accordingly.

As for those 0.1 cloud comp builds, I think they're putting faith in what their Ohm's law calculation for that precise wire length works out to as much as their meter reads, as well as faith in a higher power to protect them.

 

[Ed_C]

I love this thread. I can't count the times that I've read about someone who was using such and such $10-30 meter and calming how accurate it is. Or they think that if their meter reads to the hundredths place it must then be that accurate.

 

[Ed_C]

I just looked at the 521 Tab and they don't make any claims as to accuracy, just the range that it will read. They say it has a resistance rate of 0.2 ohms, but I'm not sure what they mean by rate.

 

[sawlight]

I just looked at the 521 Tab and they don't make any claims as to accuracy, just the range that it will read. They say it has a resistance rate of 0.2 ohms, but I'm not sure what they mean by rate.

It means it's capable of going down to .2 Ohm's, but won't register, it shuts off, below that. Owning mine I've tested this for fun, .2 it reads it, anything under, no love. It does seem fairly accurate, as accurate as anything else that is.
Funny you bumped this thread just now as I watched the Vaping biker battery interview the other day and this was touched on in that vid. Hate do to it to him again, but I guess I'll try and drag @Mooch into another hot mess and see if he can offer any insight. And thanks in advance!

 

[Ed_C]

Hrm, then why do they state that it has a "Resistance Measuring Range: 0.01 – 9.99 ohm"?

 

[sawlight]

My coil master says down to .2, at least the model I bought does.