How to determine what resistance cartomizer for what battery. How to determine what resistance cartomizer for what battery? The Chart linked below shows Volts, watts and Ohms and how they relate to your atomizer/cartomizer. Let's take an example. You have an eGo battery and you are wondering what resistance you should get for a cartomizer or if it will work. In the chart you will see values highlighted in yellow which I call the sweet spot. This is my personal sweet spot, yours may vary. You'll also see a range of values in the RED, which indicated the Danger Zone, the point at which an Atomizer or cartomizer is likely to pop or die. The chart is setup like so: – The Top row shows voltage from your battery. – The first vertical line shows the resistance of the cartomizer (note dual coils need to be doubled accordingly) – Draw a line with your finger to match the ohms with the volts and you'll have your watts which is what we will be focusing on below. Wattage is essentially “heat” and this is what we take into consideration when highlighting certain areas of the chart in red and yellow. So how does it work? Lets use the eGo as an example. The eGo battery has an output generally between 3.7 and 4.2 volts and the cartomizer is 3.0ohm, which as anyone with a eGo can tell you is quite “perfect”. Looking this up on the chart we see that this combo will range between 4.56 watts – 5.88 watts, well within the “safe” zone. So your eGo with the same volts should product the same safe result and you can vape like a fiend without too much trouble. Should you put a low resistant atomizer/cartomizer on your eGo? Yes, but you will see the wattage increase quite a bit. The low resistance are one of the more popular cart around and it's 1.5ohm and is regularly used on an eGo battery, so while it does seem a little high in wattage it will still work. Please take this chart more as a guide rather than a concrete yes or no. I have limited my sweet spot to 4 to 7watts, just because I am wimpy when it comes to electronic devices and I happen to like the output, but you can use anything that's not in the red area (12 watts or more). You could easily go up to 10+ watts or perhaps a bit more if you not a serious chain vapor. Please note: this chart isn't the end all be all, my “safe zone” and “sweet spot” are not exact and open to interpretation. The danger zone, however, is not. You can easily pop and atty with too much heat. Stay out of the red! Here is a very simplified table please consult the chart, this is for a quick look Battery/Voltage Single Coil Dual Coil 510, 901, 808 2.0 - 2.5 ohms. NO! eGo Batteries 2.0 - 2.5 ohms. 1.5-1.7 ohms 3.7v (Go-go, Larger eGo, Riva) 1.7 to 3.2 ohms 1.5-1.7 ohms 5v (Variable Voltage) 2.5 to 3.2 ohms 2 ohms 6v (Variable Voltage) 3.2 ohms and up 2.5 ohms 7v (Variable Voltage) 4.5 to 5 ohms 3 ohms Resistances Understanding resistances, LR and HV “LR” stands for low-resistance (for use on 3.7V or less batteries). “HV” stands for high-voltage. To understand this HV and LR, it helps to be familiar with Ohms Law. Power (measured in watts) is the intensity of the vape. 6-8 watts is the “sweet spot” for most vapors. Current (measured in amps) is what can burn out cartomizer. Roughly speaking: around 1.5 amps is fine; 2.0+ amps is risky. But watts and amps are not properties of cartomizer or batteries. They are derived from cartomizer resistance (measured in ohms) and battery voltage (measured, of course, in volts). The formulas: Watts = Volts X Volts / Ohms Amps = Volts / Ohms So we need to balance battery voltage with cartomizer resistance to get an ideal vape intensity (6-8 watts or so) without burning out the cartomizer. If the voltage is too low and/or the cartomizer resistance is too high (relative to each other), the watts are low and you get a poor vape (little throat hit, vapor, and flavor). On the other hand, if the voltage is too high and/or the cartomizer resistance is too low, the amps are high and you can burn out the cartomizer. Regarding Resistance and Voltage Numbers In what follows, and throughout the vaping community, we refer to cartomizer resistance and battery voltage as a set number, e.g., 2.3 ohms and 3.7V. In fact, cartomizer resistance should be viewed as +/- 0.1 ohms, e.g., a “2.3” ohm cartomizer is more like 2.2-2.4 ohms Actual battery voltage drops considerably from fresh off the charger to stopping. The “nominal” voltage is more of an average or midpoint. For example, a “3.7V” battery starts out at 4.2V fully charged and drops down to 3.2V before demanding to be recharged. With this, larger mAh batteries are desired for not only the life of the charge but the life of the charge in the sweet spot. Standard 510/eGo cartomizer A standard 2.3 ohm 510 cartomizer on a 3.4V 510 thin battery generates a safe 1.5 amps … but only 5 watts of power: not bad, but not intense enough for many vapors. That same cartomizer on a 3.7V battery like the eGo and Go-go yields 6 watts and 1.7 amps: nice vaping with little risk of cartomizer burnout. The go-go has been perfectly matched with it's proprietary cartomizer and it one of the reasons the Go-go is highly praised, but yet relatively unknown. HV cartomizer Most “HV” cartomizer are 4.5 ohms resistance and are intended for use on 6V mods (using two 3.0V batteries or a booster). NOTE: We do NOT recommend EVER stacking batteries for ANY reason, the info here is just that, info. This results in 8 watts of vaping (very nice) and 1.3 amps current (a conservative level). Some HV cartomizer are 3.5 ohms, intended for use on 5V mods: 7 watts and 1.4 amps. Others are 5.2 ohms, intended for 7.4V mods (again using two 3.7V batteries): 10.5 watts and 1.4 amps. So a correct matching of these “HV” cartomizer with these 5.0, 6.0, and 7.4 voltage levels delivers a powerful yet safe vape. LR cartomizer LR cartomizer are intended to yield vape intensity (watts) on 3.4V or 3.7V similar to what the higher voltage mods deliver. But some of them generate damaging current. The further you push the amps above 1.5, the greater the risk of burning out an cartomizer. The typical resistance of LR cartomizer is 1.5 ohms. Vapors routinely use such 1.5 ohm LR cartomizer on 3.4V eGos (7.7 watts and 2.3 amps) all the time: excellent vape intensity … but the life span of this tye of usage is much shorter due to the intensity. There is no physical danger in such high amps, nothing blows up. It’s just that 1.5 ohm cartomizer die faster than standard (or high) resistance cartomizer. Another consequence of the high amps created by 1.5 ohm LR cartomizer is that they should only be used on batteries of at least 450 mAh. So no dinky 510's!! Those various resistances on 5V, 6V, and 7.4V will generate the following watts (i.e., intensity of the vape) and amps (the current that damages cartomizer) DC Cartomizer Dual coil cartomizer seem to be all the rage lately but there is some confusion on how they actually work. A dual coil cart consists of two coils of the same resistance. They are wired in parallel so the total resistance is half the resistance of either coil. For example: The total resistance of the 1.5ohm dual coil is 1.5ohms, but the resistance of either coil it contains is 3ohms. Both coils are actually 3.0ohms individually, together they are not 6.0, they are 1.5ohms A 1.5ohm cart at 3.7V would be drawing 3.7/1.5=2.47 amps. But the single coil is burning at 3.7^2 / 1.5 = 9.13 Watts, while each coil of a dual coil 1.5ohm cart is burning at (3.7^2/1.5) / 2 = 4.57 watts. You are splitting the power between the two coils. Although you can certainly get away with it, a 3.7v device is not ideal for a DC cart, you should use a 4.5v or better. Enter any two known values and press "Calculate" to solve for the others. For example, an eGo having a rating of 3.7 volts AC and using a cart of 2.5ohms will draw 1.48 Amps and 5.476 watts. Enter 100 in the Watts field and 120 in the Voltage field and press Calculate to find the resistance and current. Fields should be reset to 0 before each new calculation. Voltage (E) = Current (I) * Resistance (R) Power (watts) = Current Squared (I^2) * Resistance (R) Power = I*E = E^2 / R