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Thread: Clearos - resistance and wattage

  1. #1
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    Clearos - resistance and wattage

    I was just looking at this
    $39.54 iTaste VW V3.0 7-in-1 Variable Voltage Rechargeable 800mAh Electronic Cigarettes Set - vv-3.0 at FastTech - Worldwide Free Shipping
    Wattage can be adjusted from 6.0 – 11.0 W in .5 watts increments.

    So I've started checking my factory made coil heads for resistance. But everytime I check I get a different result!!
    Those crappy contact joins between the coil and the body can have as much, or more, resistance as the coil.
    I'm using a multimeter and it only puts ~1mA through the coil (I think).

    I measured a head at 3.2ohm, so at 3.7v ~ 4.3w

    I measured it again, this time from the actual ends of the coil and got 2.6ohm. So I'm getting 0.6ohm in those joints. Even so, 3.7v, 2.6ohm ~ 5.3W

    Next, I took off the evod I'm currently using, tipped it on its head and measured 1.9ohms. Left it sitting like that for a while and measured again, 2.4ohms. Is e-liquid conductive?

    So whats the wattage when I'm vaping?
    Is there enough force squashing the head when its on the battery to eliminate the contact resistance?
    Is the vaping current high enough to create a good connection at these joints? A very shallow spot weld?

    What current is used to measure resistance, in those mods that can?
    Last edited by mattrix; 03-10-13 at 04:43 PM.

  2. #2
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    i don't know enough about this....to one understand properly what your talking about....and two...to let you know what it all means.

    but when the coils i make bounce around in ohm's it's usually cos there is a short somewhere or it requires further oxidising cos it's not doing what it's supposed to.

    someone smarter than me will come along and advise you mate. good luck with stuff.



    I don't need squat for ages, i just went shopping.
    $1800.61 Spent on Vaping so far, stocked up for 2 years @ 8ml/per day.

  3. #3
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    Fabricator will maybe/hopefully be along. Hes a ohm , voltage wattage genius.

    because of him I now understand (what I need to anyway)

    What you checking with ?
    Samtron likes this.

  4. #4
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    The iTaste VV V3 is excellent. I will be getting a couple to replace my twists, because I really miss not having an ohmmeter on the device when I don't or can't have the Vamo with me: it's the single most useful fault finding tool when your vape isn't working right, or if you just want to keep tabs on the health of the coil and contacts. The ohms should not be bouncing around, and it's going to cause you problems. Juice is not conductive, however most of us find the readings about 0.1 ohms high on a dry coil, which then settles down once the juice is in and the coil has been fired. There's no real reason for this, except maybe once the wire is lubricated and current passed through it, it overcomes the natural contact resistance of the stainless steel.

    First thing you should do is take the head right out of the device and put it on a piece of paper towel in front of you. Measure the ohms between the body of the head and the center pin. In theory this should be what it came out of the factory at: eg 1.8 ohms. The accuracy on factory heads is supposed to be +/- 0.1 ohm. In reality I generally find they are plus 0.1 or 0.2. Part of the reason for this is that the head is made of stainless steel, and it's not the greatest contact material on the planet. Such is life. Stainless steel is "stainless" because it generates a passivating layer which protects it from corrosion - that layer is chromium oxide which is not a good conductor.

    If it reads high and is bouncing around (high) at this point, the most likely reason is bad contact between the wire and pin, or the wire and body as you surmised but check my notes below, on using the meter. There's not a great deal you can do because removing the pin and trying to re-insert it will probably lose the wire that it is holding. You could try pulling it slightly and the seating it back again. Sometimes when we screw a device on too hard it squashes the center pin into the grommet and causes a bad contact. Another common problem with factory heads is that the wires that are not trimmed as close to the grommet as possible. When we over tighten them the grommet squashes and the bit of wire sticks out and contacts where it is not supposed to and can cause a short. You need a very fine pair of flush nippers to trim the wire back.

    Next screw the head back into the base and measure the resistance between the body of the head and the base. If you get more than zero resistance it may mean that the threads are gunked up and need cleaning. You can get some toothpaste on a cotton bud and run it firmly around the inside threads to polish them. Wash before re-inserting the head again, obviously. I've had a problem with the brown anodised Kanger heads recently (T3S and mini Protank) and this seems to have fixed the problem.

    Now check the resistance between the center pin and the base again, you should get the correct resistance reading. Push on the center pin a little and the reading should not change.

    It should now be OK to put the device back together and put it on your PV. If you're getting short circuits only when you put the device on your PV then it might be the wires sticking out as mentioned earlier, or another problem which I won't go into here. If you're getting high resistance readings only after you've screwed the device onto the PV, and it's a bottom coil, then you might have over-tightened it and pushed the pin in.

    Some heads I've just given up on and recoiled or replaced. You do occasionally get a troublesome one, though understanding the problems can often lead to a simple and quick fix.

    Just a word on digital multimeters (DMM): They are not really designed for reading low ohms, so while you can get useful readings out of them you have to make a few allowances for their failings:

    1) Set the dial to the lowest ohms range. On most digital multimeters this will be 200Ω
    2) Short the two probes out. You'll notice that it does not in fact read 0Ω. Make a note of the reading you get.
    3) Measure your coil or device, then *subtract* the reading you got in step 2. This is the true reading of the device.


    The reason that you will not get a 0Ω reading is that the multimeter is being fooled by it's own internal circuit resistance and the resistance of things like the leads and the banana plugs that connect them to the DMM. You can buy an atomiser resistance checker that gives very accurate readings, (expect to pay about $30) but they are often out of stock at the few places that carry them. The bad thing about them is that they don't have probes so can't check a coil while you building it or do the kinds of troubleshooting I've outlined above. They also can't check a battery, fuse, lightbulb or do any of the other thousand things you can use a DMM for. ;-)
    Last edited by fabricator4; 04-10-13 at 12:17 AM.
    Robray, Samtron, bikam0wz and 1 others like this.
    Chris: Tobacco free since 17:00 15th March 2013.

  5. #5
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    Thanks fabricator4, for your detailed post.

    Good points about use of a DMM.
    I had taken all that into account, and all the measures I gave were stable.
    Measuring low resistance is troublesome, the meter only generates ~1ma, which is not enough to affect any oxide layer, etc.

    I have done some more measurements. I have heads that read 2.8ohm, then on the next measure 2ohm (2.4-0.4), dry. I guess depending on how much pressure I'm applying. When vaping a single head can go from nearly no vape (high ohms), to working well, to burning my juice (low ohms) over the course of a fill, and when my vape goes wrong I see figures higher and lower than that range, as measured with the topper intact. But I have nothing that will measure while still on the battery.

    I am still learning to recognize the symptoms when my vape goes wrong. I was attributing problems to wicking, but now I'm thinking a lot relates to the power delivered to the coil, which can vary 20%+. It doesn't take much for everything to go pear shaped.

    Although I cant be sure, it appears most of the time I'm vaping at <6w, and the iTaste VV V3 minimum is 6W? How do people vape at 10W without burning their juice?
    Last edited by mattrix; 07-10-13 at 11:50 PM.

  6. #6
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    Quote Originally Posted by mattrix View Post
    Thanks fabricator4, for your detailed post.

    Good points about use of a DMM.
    I had taken all that into account, and all the measures I gave were stable.
    Measuring low resistance is troublesome, the meter only generates ~1ma, which is not enough to affect any oxide layer, etc.

    I have done some more measurements. I have heads that read 2.8ohm, then on the next measure 2ohm (2.4-0.4), dry. I guess depending on how much pressure I'm applying. When vaping a single head can go from nearly no vape (high ohms), to working well, to burning my juice (low ohms), and when my vape goes wrong I see figures higher and lower than that range, as measured with the topper intact. But I have nothing that will measure while still on the battery.

    I am still learning to recognize the symptoms when my vape goes wrong. I was attributing problems to wicking, but now I'm thinking a lot relates to the power delivered to the coil, which can vary 20%+. It doesn't take much for everything to go pear shaped.

    Although I cant be sure, it appears most of the time I'm vaping at <6w, and the iTaste VV V3 minimum is 6W? How do people vape at 10W without burning their juice?
    If that's a 2.4 ohm head and you're getting readings of 2 ohms, then that indicates it is shorting out somewhere. As mentioned the most likely culprit is a wire sticking out the side of the connector, normally on the center pin. When you screw it on too tight the wire pokes out and makes contact on the side of the connector.

    Are these factory heads? I've generally found them pretty good, but you do come across the occasional dud. Unstable resistances are going to cause you problems. Definitely go through the full trouble shooting process I outlined above. The other problem I alluded to is that if the coil is not sitting all the way down in the slot, it can be making contact with the metal press fit top. Both of these short problems show up when you screw the head down too tight because they can happen when the center pin is pushed in.

    People are running Protanks at 10W because (A) they have altered the design significantly and improved the wicking efficiency, or (B) their taste buds are still on holiday with no sign of returning yet. Sometimes I have to wonder myself but it often turns out that they've recoiled it with cotton or something. Shame they don't always say that along with the claim that THEY can run protanks at 10 watts, because it can potentially mislead people just wanting to run with the factory heads and get some kind of decent life out of them.
    Chris: Tobacco free since 17:00 15th March 2013.

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    These are factory heads, knockoffs though. I don't find them very consistent. I have heads stamped 2.4 that measure at 2 (and heads stamped 2.5 that measure at 3.1) ... goes and checks ... they are reading 2.1 now. I can't measure resistance while on the battery, so the center wire shorting isn't an issue when I'm measuring. Could be touching inside the head, but I just think its under spec.

    Anyway, I don't think the threads on my setup let you screw down tight enough to squash the head much. I've got a head thats just a smidge shorter, and its not reaching the battery properly. Unless I've managed to push the centre post of the battery down, but the other heads I've tried reach ok.

  8. #8
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    Quote Originally Posted by mattrix View Post
    These are factory heads, knockoffs though. I don't find them very consistent. I have heads stamped 2.4 that measure at 2 (and heads stamped 2.5 that measure at 3.1) ... goes and checks ... they are reading 2.1 now. I can't measure resistance while on the battery, so the center wire shorting isn't an issue when I'm measuring. Could be touching inside the head, but I just think its under spec.
    OK, possibly just a long way out of spec then. I haven't had any that were that bad.
    Chris: Tobacco free since 17:00 15th March 2013.

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    We sort of missed the point of why I was measuring in the first place.
    I was thinking a constant wattage might make my vape more consistent.

    The iTaste VV V3, can be adjusted from 6.0 – 11.0 W in .5 watts increments.

    As far as I can tell, I am currently vaping at 4-4.5W, (3.3-3.5V, 2.7ohm).

  10. #10
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    Quote Originally Posted by mattrix View Post
    We sort of missed the point of why I was measuring in the first place.
    I was thinking a constant wattage might make my vape more consistent.

    The iTaste VV V3, can be adjusted from 6.0 – 11.0 W in .5 watts increments.

    As far as I can tell, I am currently vaping at 4-4.5W, (3.3-3.5V, 2.7ohm).
    Yes, I consider it to be a weak point on the iTaste VW, however it does go low enough to run the Kanger heads at the Kanger recommended power. You like a cooler vape so your only option would be to set the volts to between 3.3 and 3.5V in VV mode. You'd still have the advantage of having an ohmmeter on the device so you could see what was happening though. If you've got coils of indeterminable resistance (that are bouncing) you are better off in VV mode in any case. I've had some nasty experiences with unstable resistances in VW mode on the Vamo. Device reads a very high resistance when the button is pressed, then blasts a low resistance coil with way too many volts.
    Quom likes this.
    Chris: Tobacco free since 17:00 15th March 2013.

 

 
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