How does 18650 provide voltages higher than 3.7v?

[Asmani]

On my 18650 battery it's written 3.7v. But when I fire at say 40w, the voltage shown on the LCD of my vaporesso Target Pro exceeds 5v. How is that possible?

 

[Robin Becker]

Your mod is regulated and takes the nominal voltage of the LI-Ion battery and convert it to 5V (Step-Up-converter, or Boost-Converter).
Similar happens also in a Power Bank device that charge mobile phones.

 

[bwh79]

Boost converter - Wikipedia

 

[sonicbomb]

To add to what Robin said:

The regulator chip in your mod separates the battery from the atomizer. The numbers on the screen are values for what it sends to the atomizer, not what is being drawn from the battery/s.

A fully charged 18650 is at 4.2 volts. 3.7 volt is the nominal voltage, meaning that on the discharge curve this is where the charge will spend the most time. See the graph below.

 

[Asmani]

Interesting graph. Does the "CAPACITY" in the horizontal axis mean the amount of charge drained from the battery? It's the only way I can make sense of it.

 

[Robin Becker]

Actually the capacity is less interesting, more interesting is the amount of Energy in Wh (Watt-Hour) in the battery. The Energy you calculate as a multiplication of Capacity x Voltage and is actually the surface below the discharge curve.
If a battery A has higher Voltage with the same capacity like battery B, it has more Energy.

 

[sonicbomb]

The graph was grabbed randomly and was meant to demonstrate that the discharge curve flattens around 3.7 volts

 

[DaveP]

Think of batteries in terms of voltage being analogous with water pressure. I know it seems like an apples and oranges comparison, but the theory is similar. A full tank can deliver great water pressure. As the tank empties over time the water pressure (voltage) and volume delivery in gallons per minute (Amperage) falls off.

Your electronic mod will synthesize and control the voltage delivered to the atomizer and keep it at the setting you choose as the battery voltage falls. Mech mods just fall off in vapor delivery in a linear fashion as the battery voltage drops. At some point neither a mech or an electronic mod can keep up and you have to replace the battery.

This article explains how that happens.
https://www.electronics-tutorials.ws/blog/voltage-multiplier-circuit.html

 

[Robin Becker]

Think of batteries in terms of voltage being analogous with water pressure. I know it seems like an apples and oranges comparison, but the theory is similar. A full tank can deliver great water pressure. As the tank empties over time the water pressure (voltage) and volume delivery in gallons per minute (Amperage) falls off.

Your electronic mod will synthesize and control the voltage delivered to the atomizer and keep it at the setting you choose as the battery voltage falls. Mech mods just fall off in vapor delivery as the voltage drops. At some point neither a mech or an electronic mod can keep up and you have to replace the battery.

This article explains how that happens.
https://www.electronics-tutorials.ws/blog/voltage-multiplier-circuit.html

I have another example...think about you and your girl-friend.

She wants every week a gift that cost the same (lets say 100 USD).
You work for that and all of a sudden your ...-hole boss reduce your loan per Hour.
Now you will have to work longer to be able to buy her the gift she is used to get...

 

[DaveP]

I have another example...think about you and your girl-friend.

She wants every week a gift that cost the same (lets say 100 USD).
You work for that and all of a sudden your ...-hole boss reduce your loan per Hour.
Now you will have to work longer to be able to buy her the gift she is used to get...

She's spoiled rotten! Change the gift giving cycle to her birthday and Christmas and various random occasions and she will appreciate it more.