Error message: Ohms too high

[KurtVD]

I've built a nice coil with 28Ga SS316L wire, and due to the thin wire and the large deck of my RDA (about 8 oder 9 wraps needed to fill the space), the resistance at room temperature was over 1.7 Ohm. When I wanted to test fire it with 30 Watts (in my Pico 75), the display showed "Ohms too high" (it quickly climbed to 2.5 Ohm, I think). So I made another one with one less wrap, but with something over 1.5 Ohm, I still got the same error message when firing. Without thinking too much, I trashed it and made a coil out of thicker wire, but now I got to thinking: Was I simply using too much power, and have I trashed two perfectly good coils? How much power would I need? So far, I've only used sub-ohm coils with resistances mostly around 0.5, would the taste/flavor be different? I think I've read that high-Ohm coils produce less vapour and prolong battery life, correct?

 

[sonicbomb]

In power mode the maximum resistance on your mod is 3.5 ohms, in TC mod it's 1.5 ohms. SS will increase in resistance as it heats.

With a regulated mod the resistance of the coil is not really important. The important factors are coil mass and surface area, and the power you apply to it.
Understanding the relationship between power and coil resistance | E-Cigarette Forum

 

[Foggy Road]

First problem... Sounds like you're in TC mode? Pico won't fire over 1.5 ohm in TC mode, you'll have to change to wattage. Your coils were probably fine.

I don't understand the ohm jump to 2.5 unless you're in TC mode and the mod went wonky reading the coil.

In my opinion 30 Watts was waaaay too much for those coils. I'd start at 8-10 Watts and increase or decrease from there.

Taste flavor? Subjective, more dependent on the atty itself. I vape high ohm low power for the hit. Less dense cloudage but with high nic high PG juice you really feel it but in a different way than subohm.

Hope this helps.

 

[tailland]

Maybe you're running into a consequence of Ohm's law that is usually ignored when talking about regulated mods: Insufficient voltage.

If your coil really has 1.5ohms resistance, and you dialed in 30 watts, then it means that the voltage must be regulated to 6.7volts, so the drawn current would be 4.47amps, in order to achieve 6.7x4.47=~30W. The single battery pico might not be able to do that.

I have searched for documentation, but I cannot find the pico's maximum voltage output, so I can't tell whether or not this is your problem. However, you can test it. Set your mod to 10watts and fire, then to 15 watts and fire. If the above is true, it will fire at 10, maybe still at 15, but not at 20.

 

[ShamrockPat]

You've got a whole bunch of 'things' all going on at the same time. Ohms law and the constraints of your mod will dictate what will occur. Dunno about your Pico, so I'll mention your DNA75, where the vendor publishes their specs. It has a 6.2V maximum output voltage. So on that mod with your 1.7 Ohm coil, the max watts would be 22.6, BUT SS changes it's resistance by ~20% at normal vaping temps, so when heated would be around 2.04Ω, and 19watts. The 'ohms too high' is really just informational as your mod will ride that max V value while lowering the watts.

As far as the heat for a new coil, read up on 'heat flux' on Steam engine.

 

[DaveP]

Try 10 wraps 28 gauge SS316L with a 2.5mm diameter coil. You'll be around 1 ohm and that should be fine. Install two of those for a dual setup and you'll be at .5 ohms, which is also a safe range for battery life.

30 watts is 30 watts. Coil mass determines whether the coil will perform well at a given wattage. If you want to vape at 30W you might be better off with a larger wire gauge and fewer turns.

Go here and play around with the values. Heat flux in the bottom right corner will tell you where the wattage sweet spot lies for the coil parameters you enter

Coil wrapping | Steam Engine | free vaping calculators

 

[Foggy Road]

You've got a whole bunch of 'things' all going on at the same time. Ohms law and the constraints of your mod will dictate what will occur. Dunno about your Pico, so I'll mention your DNA75, where the vendor publishes their specs. It has a 6.2V maximum output voltage. So on that mod with your 1.7 Ohm coil, the max watts would be 22.6, BUT SS changes it's resistance by ~20% at normal vaping temps, so when heated would be around 2.04Ω, and 19watts. The 'ohms too high' is really just informational as your mod will ride that max V value while lowering the watts.

As far as the heat for a new coil, read up on 'heat flux' on Steam engine.

DNA 75? I'm not aware of any Pico mod with A DNA board. (And I'm admittedly FAR from knowing it all)

With all the variants of Pico now available, I assumed the reference to Pico 75 meant the original 75w version of which I have 3. Many folks have gone to calling it that. Probably better to refer to it as Pico V1.

 

[ShamrockPat]

DNA 75? I'm not aware of any Pico mod with A DNA board. (And I'm admittedly FAR from knowing it all)

You are correct sir. Only mentioned as they have published specs, so used as an example.

so I'll mention your DNA75, where the vendor publishes their specs

 

[KurtVD]

Thanks for all your answers, this helps a lot. Yes, I’m usually in TC mode, but I switch it into power mode to test fire the coil and check for hot/cold spots, and that’s when I got the error message. And it didn’t have enough power to get the coil to glow, but I guess that’s what some of you were saying when you calculated the power requirements. Unfortunately, my original message was incorrect, and the problem had happened with my other mod, the Htcigar Vtinbox (DNA 75 board).

 

[ShamrockPat]

@KurtVD ONLY TALKING ABOUT YOUR DNA MOD AGAIN.

I’m usually in TC mode, but I switch it into power mode to test fire the coil and check for hot/cold spots, and that’s when I got the error message

If you 1st test fire in temp mode look at the initial resistance/Ω. Then go to power mode for your test fire/checking. Now look at the Ω's and they should be higher. BUT if you then go back to TC you should notice your mod has retained the initial and much lower value.

 

[Baditude]

When I get the "Ohms too high" message, I turn down the wattage setting until the message stops.

 

[ShamrockPat]

ONLY TALKING DNA MODS AGAIN.

When I get the "Ohms too high" message I turn down the wattage setting until the message stops.

Why, when the mod will ride the max output voltage nicely, and automagically lower itself. It's just informational.

 

[Baditude]

ONLY TALKING DNA MODS AGAIN.Why, when the mod will ride the max output voltage nicely, and automagically lower itself. It's just informational.

I realize that. My DNA fired the coil fine. I just figured my DNA mod "didn't like" the higher wattage setting because it gave me the error message.