Max voltage / nominal working voltage / output voltage?

[JohnMaguire2013]

I recently bought a VAMO and an 18650 battery as well as two 18350 batteries. I'm incredibly confused on what "max voltage" and "nominal working voltage" on a battery means.

I know that when I charge my 18650 battery fully, my VAMO reads it as 4.2V. I also know that if I'm vaping at 8 watts on a 2.5 ohm atomizer, I'm vaping at 4.4 volts. How am I vaping at 4.4 volts if my battery has a maximum voltage of 4.2 volts? Furthermore, what is nominal working voltage? My battery has a nominal working voltage of 3.7V (and I don't really know what that means) but my current charge is 3.6V. What voltage charge on the battery is dead? 3.2V? Is the nominal working voltage the median charge?

I've also noticed that the battery tends to stay around 3.7V charge longer than any charge (though 3.6V and 3.8V also seem to hang around longer.)

Can someone explain "how does battery work" to me?

Thanks a ton!

 

[Papadragon]

The vamo has a power regulator in it !! It regulates the power

 

[Papadragon]

The battery has a max hold of 4.2 volts of power !! The regulator will regulate that to 4.4 it will draw more power from the battery !!

 

[WarHawk-AVG]

The vamo has a power regulator in it !! It regulates the power

It has MORE than just a regulator

It has a Boost/Buck circuit (called buck/boost converter in electronic circles]...circuitry inside to boost the voltage of battery well ABOVE the voltage delivered, then bucked down (regulated down) to the proper voltage, this is why it may be pushing 8 watts to the head, but it's pulling 10 watts of current from the battery [now you understand why people recommend you put GOOD higher than normal current draw batteries in an APV?]

ex. DC DC Converter Boost Buck Step Up Step Down Voltage Module 3 5 28V to 1 25 26V | eBay

 

[Thrasher]

ok..
the battery is rated to run at 3.7 this is where they will give the longest part of their charge.

they can be charged all the way up to 4.2v then slowly drop to the 3.7 range where they stay for most of their life.

the vamo and other regulated mods have chips in them that pull extra current from the battery then convert that to a higher voltage then the battery can produce so the vamo may be running at 4.4 volts and putting out 10 watts, what is really going on is the vamo is taking 4.2 volts at 14 watts then turning the extra watts into volts.

 

[JohnMaguire2013]

Hrm. Is this why some people like to run stacked setups (nominal voltage of 7.4V) instead of using the circuitry boost? And why does it make a difference to directly draw the voltage from the battery rather than using the circuitry's boosting method?

I'm also confused by the statement "taking 4.2 volts at 14 watts then turning the extra watts into volts."

And thanks WarHawk for the Wikipedia link, checking it out now!

 

[dam718]

Without getting into the nitty gritty details of the engineering aspects that make this happen, I'll try to simplify as much as possible... APV's (for the most part) are using voltage regulators and/or voltage boosters. A Voltage regulator can effectively drop the voltage across a load to achieve a lower voltage than the output of the source. So in the case of a battery at 4.2V a voltage regulator can drop that voltage down to say 3.7V, and divert the rest of the voltage to a dummy load somewhere else in the circuit. It's not particularly efficient, but it does the job well and delivers a clean signal.

Your Vamo is using a voltage booster exclusively... A booster uses amplifiers to boost the voltage from the source to a higher level. On a Vamo (and many other mods) there are only two voltages that are ever seen at the 510 connector. 0V and 6V. So every single time you fire the device, it is firing at 6V.

Confused yet?

It uses something called PWM, or Pulse Width Modulation, and fires the device at 6V in a specific duty cycle to produce anything from 3V to 6V. It cycles 33.3 times per second, or 33.3Hz. For each cycle, it is only firing at 6V long enough to produce an average output voltage that matches the setting you have on the device. So, for a 3V setting, it is firing at 6V for half the cycle, and off for the rest of the cycle (A 50% Duty Cycle). At your setting of 4.4V it is firing at 6V for 73.33% of the cycle, and off for the remainder of the cycle. This yields an average output of roughly 4.4V RMS. It's a very similar concept to how fuel injectors work in a car, if you're mechanically inclined. If you fired your Vamo at 6V, it would be at 6V the entire time, also known as a 100% duty cycle.

So... The easy explanation is... Your Vamo is using a voltage booster only to boost the battery to 6V, no matter what the actual battery voltage is.

Most of your assumptions about the battery are correct. The battery has a max voltage of 4.2V at full charge. It has a nominal voltage of 3.7V (This is the rated output), and a low cut out on the Vamo around 3.3/3.2V... 3.7 is the average voltage, and its peak charge is .5V higher (4.2) and cutoff is .5 lower (3.2). You don't want to go lower than that or you can deep cycle the battery which kills the cell and you won't be able to charge it again. Most good chargers will cut off at 4.2V, and most good devices will cut off around 3.2V on the low end. The 3.7V, or rated output, is just a peak to peak average, and is usually the rating given to a particular cell.

 

[JohnMaguire2013]

Without getting into the nitty gritty details of the engineering aspects that make this happen, I'll try to simplify as much as possible... APV's (for the most part) are using voltage regulators and/or voltage boosters. A Voltage regulator can effectively drop the voltage across a load to achieve a lower voltage than the output of the source. So in the case of a battery at 4.2V a voltage regulator can drop that voltage down to say 3.7V, and divert the rest of the voltage to a dummy load somewhere else in the circuit. It's not particularly efficient, but it does the job well and delivers a clean signal.

Your Vamo is using a voltage booster exclusively... A booster uses amplifiers to boost the voltage from the source to a higher level. On a Vamo (and many other mods) there are only two voltages that are ever seen at the 510 connector. 0V and 6V. So every single time you fire the device, it is firing at 6V.

Confused yet?

It uses something called PWM, or Pulse Width Modulation, and fires the device at 6V in a specific duty cycle to produce anything from 3V to 6V. It cycles 33.3 times per second, or 33.3Hz. For each cycle, it is only firing at 6V long enough to produce an average output voltage that matches the setting you have on the device. So, for a 3V setting, it is firing at 6V for half the cycle, and off for the rest of the cycle (A 50% Duty Cycle). At your setting of 4.4V it is firing at 6V for 73.33% of the cycle, and off for the remainder of the cycle. This yields an average output of roughly 4.4V RMS. It's a very similar concept to how fuel injectors work in a car, if you're mechanically inclined. If you fired your Vamo at 6V, it would be at 6V the entire time, also known as a 100% duty cycle.

So... The easy explanation is... Your Vamo is using a voltage booster only to boost the battery to 6V, no matter what the actual battery voltage is.

Most of your assumptions about the battery are correct. The battery has a max voltage of 4.2V at full charge. It has a nominal voltage of 3.7V (This is the rated output), and a low cut out on the Vamo around 3.3/3.2V... 3.7 is the average voltage, and its peak charge is .5V higher (4.2) and cutoff is .5 lower (3.2). You don't want to go lower than that or you can deep cycle the battery which kills the cell and you won't be able to charge it again. Most good chargers will cut off at 4.2V, and most good devices will cut off around 3.2V on the low end. The 3.7V, or rated output, is just a peak to peak average, and is usually the rating given to a particular cell.

Wow, thanks so much. This just about completely cleared up the confusion. Just one more question, since you mentioned RMS. I know that RMS is root mean square, and AVG is average. I don't fully understand how they work but as I understand it, AVG is good for mods that don't use PWM or pulsed outputs (6V, 0V) and RMS is good for ones that do. If I remember correctly, I read that in AVG mode, if you attempted to set it for 6V, it would see (6-0)/2 = 3V, and attempt to compensate, thereby setting it to something like 12V/0V. Is that correct? I had my VAMO on AVG at first, and it was insanely strong hits and ended up burning a few atomizer heads before I caught on to the fact that I needed to switch it to RMS.

How would this work if the VAMO can only do 6V and 0V? Did it change it to do 6V 100% of the time?

Thanks again.

 

[dam718]

When using stacked 18350 batteries in a Vamo / Zmax, it still regulates the device to 6V, but increases the amount of current (Amps) the device can deliver. It allows it to actually fire low ohm (1.5-2.5 Ohms) atomizers at a higher voltage. With a single 18650/18350 the current limit is a bit lower, so even if you attempted to fire a 1.5 ohm coil at 6V, it would never actually hit 6V... With the stacked batteries, because the current limit increases, you can fire the 1.5 Ohm at 6V all day, (Limited to 15W) and it will pop the coil... Probably a poor explanation, but that's the basics... Effectively, you should never need to run stacked 18350's, unless you like how the screen gets brighter?

 

[dam718]

What I described was average calculation using the equation you mentioned... So for a 3V setting, use 6/3=.5, or 50% cycle.

So when I said 4.4V is 73.33, that is 4.4V AVG, not RMS. My mistake there...

I would have to crack open some books to determine the formula used to calculate the duty cycle of a 6V offset to get 4.4V RMS. It's probably not something I would be able to write using the character sets provided on the forums

That's crazy engineering stuff...

But yes, using AVG mode is going to result in a much hotter output than intended. Most PWM devices these days are using RMS only (no more AVG mode).

To answer another question you had, the Vamo never fires higher than 6V. The reason it was hotter is because the duty cycle is higher in AVG mode than it is in RMS mode. So, that 4.4V AVG duty cycle would be more like 5.2V RMS. You ALWAYS want to use RMS. Devices that aren't using PWM have no need to use AVG or RMS, as that is only used to compute the duty cycle of the high peak offset voltage. In an old school voltage regulator type setup, (analog circuits as opposed to digital) you just simply use a potentiometer to adjust the output voltage til you get what you want. No need for all those crazy calculations.

 

[JohnMaguire2013]

Can't thank you enough for answering all these questions.

 

[Thrasher]

We come here with the intent to quit smoking and walk away with a basic understanding of ohms law and electronic theory lol

 

[Strontium]

Can't thank you enough for answering all these questions.

Safety tip again.
Do not run stacked unprotected batteries unless you have proper equipment to match those 2 batteries. This is important because all 18350 are coming from China.