Resistance

[chrisjw]

OK, I want to get my head around this.........What actually determines the resistance of the different vivi nova heads........They are supplied with 3 different resistances........1.8, 2.4 & 2.8 ohms........What makes them different?......is it the wick size?......coil wire size?.............I ask, because I am re-coiling & wicking a few.

[Moon]

Length and diameter of wire.

Thinner wire gives higher resistance, less length required to give the same resistance as thicker wire.

The heads you have will all use the same wire, so there will be more coils on the higher resistance heads to give the longer length.

[blakey]

Nov 19, 2012 21:19:13 GMT Moon said:

Length and diameter of wire.

Thinner wire gives higher resistance, less length required to give the same resistance than thicker wire.

That about sums it

[Moon]

Nov 19, 2012 21:21:44 GMT blakey said:

Nov 19, 2012 21:19:13 GMT Moon said:

Length and diameter of wire.

Thinner wire gives higher resistance, less length required to give the same resistance than thicker wire.

That about sums it

I was crap at physics at school as I found it dull as.

If they'd done vaping classes, they could have taught me so much more...

[OneDay]

Chris imagine the wire as a length of hosepipe full of water that you are trying to blow through. The longer the hose, or the wider the diameter, the more water it will hold and the harder you (the battery) will have to push to get the water through. If you had a shorter or narrower hose you could blow the water through more easily - it would give you less resistance

[DiscoDes]

Nov 19, 2012 21:27:32 GMT OneDay said:

Chris imagine the wire as a length of hosepipe full of water that you are trying to blow through. The longer the hose, or the wider the diameter, the more water it will hold and the harder you (the battery) will have to push to get the water through. If you had a shorter or narrower hose you could blow the water through more easily - it would give you less resistance

Erm, i'd say the narrower the hose the harder - more resistant - less current

Wider - less resistant - more current

just saying

[thundercat]

oh god I thought I had it there with the first hose analogy. now confused again. Does the thinner hose not just squirt it out faster?

Andy

[ant]

Oneday, I need to pee now

[chrisjw]

So, to re-cap............. I tend to use 2.4ohm heads more than the others.............To coil one the same then, I would use, say, 0.16mm wire with maybe 5 coils. If I were to make a 1.8ohm head, I would use 0.20 wire with less coils.......Lastly, what are the benefits of a single or double wick & longer to shorter wicks?

[chrisjw]

Nov 20, 2012 8:24:42 GMT chrisjw said:

So, to re-cap............. I tend to use 2.4ohm heads more than the others.............To coil one the same then, I would use, say, 0.16mm wire with maybe 5 coils. If I were to make a 1.8ohm head, I would use 0.20 (or 0.16) wire with less coils.......Lastly, what are the benefits of a single or double wick & longer to shorter wicks?

[martym9]

Resistance is futile..... (someone had to say it)

[esmecullen]

Nov 20, 2012 9:38:56 GMT martym9 said:

Resistance is futile..... (someone had to say it)

beat me to it

[chrisjw]

Nov 20, 2012 9:38:56 GMT martym9 said:

Resistance is futile..... (someone had to say it)

I don't think I'll ever be able to post anything that's taken seriously......................I love it........

[J_Mac]

Nov 20, 2012 0:31:08 GMT thundercat said:

oh god I thought I had it there with the first hose analogy. now confused again. Does the thinner hose not just squirt it out faster?

Andy

It might be better to imagine a mountain lake feeding a river. I find this better when working with physics students.

Voltage = steepness of the mountain. Current = flow rate of water in river. Large current = hot wire!

A steeper mountain gives a higher flow rate but this is constrained by the width of the river. A wider river allows a higher flow rate.

Then the resistivity of the wire can be taken into account. Imagine copper wire as a very smooth bottomed river. Not as much steepness is required to get a large current flowing so the wire will get hotter at lower voltages. A high resistivity wire such as kanthal or nichrome is like a rocky-bottomed river so requires higher voltages to get a big current flowing and consequently will not get as hot.

Why not use copper then? There needs to be a decent load for the battery to work on otherwise power is dissipated from the battery itself and this can lead to wasted energy, hot battery and maybe shorter battery life. This is called 'voltage drop' and is caused when the internal resistance of the battery is significant compared to the resistance of the load. 

Sorry to resurrect an old thread, I was searching for the effect of increasing wire diameter while decreasing length of a coil at constant resistance and couldn't resist being an annoying physics nerd 

[fred]

Nov 20, 2012 10:35:21 GMT chrisjw said:

Nov 20, 2012 9:38:56 GMT martym9 said:

Resistance is futile..... (someone had to say it)

I don't think I'll ever be able to post anything that's taken seriously......................I love it........

There was a rewicking tutorial on Radio 4, 5 minutes ago.

Bet you missed it, as you were listening to Daft Punk on a different station 

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More seriously,
5 on the top & 4 on the bottom of 0.16 nichrome around 2mm wick gives me about 2.2ohms.

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Ooops - didn't realise this thread had just been woken from deep sleep - you were probably better off listening to Daft Punk anyway, having sorted out rewicking months go