How to calculate wattage with Dual Batteries?
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Let me quote my friend Ryedan on this matter, who says it better than I could:
Ryedan said:A lot of people don't understand how battery amp draw in VW devices works. Sometimes I think we're still stuck back in the mechanical and VV mod days
Here's my explanation of it from another thread. To summarize, atty resistance in a VW device has nothing to do with battery (as opposed to device) amp rates. At 165 watts with two batteries in series each battery would see a 28.65A draw with battery voltage at 3.2V. With the battery voltage at 4.2V they would see 21.83A draw. This is true at 0.1 ohms and at 4.0 ohms.
It also doesn't matter if two batteries are in series or parallel in a VW mod, amp draw on each will be the same at 165 watts in both cases.
From Steam Engine, for your example above, 165w at 0.1 using two series batteries at 6.4 battery volts pulls 28.65A from each battery. At 8.4V it goes down to 21.83A. That's at 90% regulator board efficiency. And it will be the same amp draw with a 4.0 ohm atty, however that would require the regulator to output 25.69V and that isn't possible at the moment so we can't vape at 165 watts with a 4 ohm atty today.
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Someone needs to take me to school on this because I still don't understand.
Basically, I want to know how much wattage i'll be pumping out with a dual 26650 unregulated box mod, and depending upon the batteries and resistance I use i'll need a formula to calculate the wattage output. Then I can use this formula for dual 18650's as well.
I need something along the lines of:
a + b + c = wattage
There's online calculators for determining wattage with a single battery, but not with dual or triples. And that's my hangup here.
Basically, I want to know how much wattage i'll be pumping out with a dual 26650 unregulated box mod, and depending upon the batteries and resistance I use i'll need a formula to calculate the wattage output. Then I can use this formula for dual 18650's as well.
I need something along the lines of:
a + b + c = wattage
There's online calculators for determining wattage with a single battery, but not with dual or triples. And that's my hangup here.
Wattage is based on the voltage going to the coil, and the coil resistance. When connecting batteries in series the voltage doubles. You still use the same formula to calculate wattage.
volts x amps = watts. If batteries are stacked like in a flashlight, then they are what is called "in series". One + and one - on top of the box mod. If both + are on the top of the box mod then they are called "parallel". Now the next part.....when in series, you add up all the volts when fully charged and there is your voltage. For parallel voltage stays the same whether one battery or a hundred. Example, 18650 battery fully charged is 4.2v. If I had two in series, I would have 8.4 volts.
Make it simple for you.
Makes no difference how many cells you have. Do you know how to calculate wattage for one cell?
2 cells parallel is 4.2v
2 cells in series is 8.4v
Online Conversion - Ohm's Law Calculator
Makes no difference how many cells you have. Do you know how to calculate wattage for one cell?
2 cells parallel is 4.2v
2 cells in series is 8.4v
Online Conversion - Ohm's Law Calculator
Ugh... math class for Journeyman Electricians... the short "For Dummies" version...
watt's 1st law. (voltage x voltage)/resistance=wattage.
Amperage = (watts/volts)
parallel or single battery(4.2x4.2)/0.2 = 88.2W or (88.2/4.2)=21A
Most regulated mods are wired in series, but the circuitry controls output making the math irrelevant. If you have an unregulated mod wired in series...
(8.4x8.4)/0.02 = 352.8W or (352.8/8.4)=42A
Resistance significantly effects output wattage as it determines how much energy is required to push the current through the circuit. Think of a water hose and think of the coil as a bucket you are trying to fill with water. When it is full, you are at the temperature you need to vape. Your batteries are the faucet. Higher voltage is like opening the faucet wider. If you turn it on and let it flow freely (low resistance) you get a lot of water really fast. If you put your finger over the end (higher resistance) you get a lot of back pressure, but less water.
watt's 1st law. (voltage x voltage)/resistance=wattage.
Amperage = (watts/volts)
parallel or single battery(4.2x4.2)/0.2 = 88.2W or (88.2/4.2)=21A
Most regulated mods are wired in series, but the circuitry controls output making the math irrelevant. If you have an unregulated mod wired in series...
(8.4x8.4)/0.02 = 352.8W or (352.8/8.4)=42A
Resistance significantly effects output wattage as it determines how much energy is required to push the current through the circuit. Think of a water hose and think of the coil as a bucket you are trying to fill with water. When it is full, you are at the temperature you need to vape. Your batteries are the faucet. Higher voltage is like opening the faucet wider. If you turn it on and let it flow freely (low resistance) you get a lot of water really fast. If you put your finger over the end (higher resistance) you get a lot of back pressure, but less water.
OK, even easier. Hook it up and fire it, if it burns your eyeballs, turn it down, if you dont get a good throat hit, turn it up. I assume you are trying to figure out which mech to buy, go to a nice shop and ask them to let you try out a few on your tank. Then once you have it figured out, tip them a fiver.
ZERO wattage from the mod............... ALL WATTAGE is drawn by the COIL. Here study this, Steam Engine | free vaping calculators
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