A simple wattage chart showing the relationship between voltage and resistance

I don't get to this sub-forum as often as I would like, but I noticed there's always a few questions about voltages and resistances.

What's wattage? Wattage is a measure of power. It is determined by both the input voltage and the resistance of your coil.

In simple terms, for personal vaporisers it determines how hot your coil gets, and thus has a direct impact on the amount of vapour you're producing, so it's a good idea to understand this concept. There's a lot more factors involved in optimal vapour production, but I won't get into those right now.

Below is a wattage chart, there are many like it on the internet, but this one is mine (a bit tarted up for public consumption).

Full res version here: http://i.imgur.com/6oraBGI.png




Here's a few pointers to explain how this is relevant for a few different user groups...

Joye eGo users:

• Joye eGo batteries have a regulated output of 3.3V, meaning that the output voltage can't be changed. Therefore in order to change your wattage you have to change to a coil of higher or lower resistance.
• Clearos and cartos designed for eGos will typically range from 2.2Ω (5 watts) to low resistance 1.6Ω (6.8 watts).
• It is not advisable to use less than 1.8Ω with Joye eGo batteries, otherwise you will begin to compromise the life of your battery.

Variable Voltage users:

• The best advice is to dial up to taste. Start at the minimum voltage your device can provide, usually 3.0V, and the incrementally increase the voltage until you are happy with the vapour production.
• Generally, if you are using a clearo or carto, you will end up somewhere between 5 and 10 watts. If you are using a rebuildable, you may find yourself somewhere in the range of 8 to 13 watts.

Variable Wattage users:

• Well you're just all sitting pretty aren't you? No need to look up charts huh? Just dial in your watts and bang on any old atomizer huh?
• Wrong. I've got another chart for you which I'll come back and post later.

Mech Mod users:

• No regulation... living life on the edge eh?
• You should already be familiar with these concepts, but if not go through them again.
• I'll might discuss C ratings later, but that may be a little advanced for the New Vapers Forum.

Additional topics
Wattage - you are here now
Joye eGo and regulated output
Vaporisation Theory - The Simple View
Vaporisation Theory - The Complex View: The Coil & Air Flow
Vaporisation Theory - The Complex View: The Wick
Vaporisation Theory - The Complex View: The Juice
Amperage Theory
Amperage Theory - Vamo, Smok Zmax v2, SVD, Provari v2 (coming soon)



If you're a new vaper (or old one) with a few questions about voltages and resistances, leave your questions here and I'll try to get to them over the weekend.

More experienced vapers, also feel free to chime in with your experiences.

 

your spot on mate with the wattage thing "just set it and leave it" i bet if you set your device to 11W and wack a brand new 1.5ohm coil on there something very unpleasant will happen if you know what i mean? POP POP!! burn burn! VV IMO is just as simple if not easier and gives you a less of a chance to fry your toppers. IMO alot of vapers get brain washed in "it has to be VW" Well no it doesent... it can be VV, very easy to know your voltage based on your resistance, doesnt take any longer to dial in your voltage then to dial in your " set it and leave it Wattage and never have to touch it ever again no matter what i put on my device"

 

I think I'm going to add bits and pieces to this thread as time goes on. I haven't got any sort of plan, just slapping things down on paper as I go.

The next instalment covers an important feature of eGo devices.

Joye eGo and regulated output

eGo-style batteries are a popular starting point for vapers who are looking to improve on cig-a-likes. They provide a decent battery life, and have a little chip in them that provides a nice little set of features including regulated output, amp limitation, low voltage protection and overcharge protection.

For the purposes of this particular discussion about wattage, let’s focus on the regulated output.

All batteries have a nominal voltage. For common AA batteries it’s 1.2V. However as you can probably guess from the charts, 1.2V isn’t going to give us the greatest vaping experience. That’s why virtually all personal vaporisers use a lithium-ion battery. Unlike your typical AA battery which has a nominal 1.2V output, lithium-ion batteries have a nominal 3.7V output, which much better suits our needs.

The word “nominal” just means what it says on the label. Batteries fresh off the charger actually start at a voltage higher than their nominal value, and will decrease to a voltage lower than their nominal value before they die. For lithium-ion batteries, the safe operating range is actually 4.2 to 3.4V.

This is where voltage regulation is kicks in.

Let’s say you’re using a 2Ω clearo. If you were vaping with an unregulated PV with a fully charged battery you’d start out at 4.2V, which gives you 8.8W. As the battery is used during the day, it will slowly decrease to 3.4V, which gives out 5.5W. As you can guess, be.comse of the decreasing voltage the performance drops dramatically during the life of the charge. In order to combat that, the eGo has a chip which regulates output to 3.3V, meaning that for the large part, your output is consistent at 5.2W throughout the day. You may be asking why this trade-off for lower voltage is better. It’s be.comse when you’re starting out with vaping it’s more about consistency than total output.

Remember, if you want to bump up your performance you can always change to a clearo with a lower resistance. For example, changing to a 1.8Ω clearo will give you 6.1 watts of power, and be.comse of the regulated output, you’ll get that all day.

To work this out for yourself, refer back to the wattage table above. Be.comse of the regulation in eGo devices it’s a real doddle. The only row you need to be concerned with is 3.3V (I’ve even put an arrow in there for you to make it foolproof). Now read across the resistances to 1.8Ω and you can see that it will give you 6.2 watts of power. Increase your resistance to 2.2Ω and you get 5W. Easy


Additional topics
Wattage
Joye eGo and regulated output - you are here now
Vaporisation Theory - The Simple View
Vaporisation Theory - The Complex View: The Coil & Air Flow
Vaporisation Theory - The Complex View: The Wick
Vaporisation Theory - The Complex View: The Juice
Amperage Theory
Amperage Theory - Vamo, Smok Zmax v2, SVD, Provari v2 (coming soon)

 

I run it this way, it's what personally works for me:

VV I add 2 volts to the ohms as I was sick of looking at a chart. Usually gives you about 8 watts. Adjust up or down according to taste.

VW I start at 8 watts and adjust up and down according to taste.

Mech mod I usually build about a 1.5 ohm coil and everything seems OK. Smaller batteries like 14500, 18350 or 18500 seem to work fine with lower ohm builds on BDA/RBA.

Just my 2 cents worth, plus GST

 

Heh. Never realised how good an approximation that is. I'll be sure to steal it when I write up the VV section

 

Brilliant chart, thanks for the info luntingsir.

Do you know if clones like my first starter kit have the "smart chip" in them?

Based on their blurb I am guess they don't offer everything but I am glad they have the overcharge protection.
"A fully charged eGo K 1100mAh battery can work at 4.2v and last 1200 puffs at most. When the battery power decreases, the battery output voltage will decrease. The battery will stop working at 3.0v. Each battery comes with overcharging protection."

 

TVS have one posted on their site,
looks pretty accurate but use at your own risk

 

All I got is AkkuDB
I'd like any other resource available too

 

vv/vw draws more Amps when the battery voltage is lower. e.g. At 20w and the battery at 3.8v it's 5.3A, at 3.3v is 6.1A.(6.7A est +10% for loss on conversion.)

 

Wow reading this series at the end of March 2015 and its still pretty useful....bumped

 

I agree nicoand.comghter. Just .comght this be.comse of your bump, and it is useful for me particularly now I have started to build my own coils and have just started with an RBA.

Thanks luntingsir, this is golden information!

 

It's a bit of a .comgh looking back at this. When this was first written in the middle of July 2013 sub-ohming had really just got started. People were pushing the boundaries with 0.9 ohm builds. Silica was still the choice of wicking material, cotton was yet to be heard of. Steel cable was hailed as the solution to genny wicking issues..comto-drippers had yet to be utilised. Actually, whatever happened to them? They seemed to be a legitimate way of getting all the benefits of a dripper, but the convenience of a tank.