Loaded Voltage

[tonyfalkon]

I have always wondered what the loaded voltage reading is when vaping in HV battery. After seeing this video I think by now everyone has seen this, I wondered to myself is that was because of the density of the materials used somehow affected the voltage, there has been some discussion about this but no concrete evidence yet so I tried it myself.

I used this as my test set thanks to RalphT for coming up with this one.

2 freshly charged Tenergy 3.0v LiFePO4

510 atty resistance

Loaded Voltage

Amp check on the positive connection

Amp Check on the negative connection

This is the Battery Specs

New Chemistry LiFePO4 Li-Ion batteries:
Rechargeable LiFePO4 RCR123A 3.0V 750mAhBattery
Life cycle: 2000 times (Traditional Li-ion: 500 times)
Never explode or catch fire
Working Voltage:3.2V and Peak Voltage: 3.6V
Charging cut-off voltage: 3.6V
Discharge cut-off voltage: 2.2V
Please never overdischarge battery below 2.2V/cell
Charge the this battery with LiFePO4 RCR123A smart charger.
Capacity: 750 mAh
Maximum discharging rate:< 550 mA
Maximum charge current: <550 mA
Cell's dimension: 17mm Dia. x 34.5mm H.
Weight: 0.6 oz (18 grams).

After performing this experiment I had more questions than answers, are we really vaping 6v or 5v, I have no background in electronics and most of the people I asked about voltages always refer me to ohms law.

This a quote by one of the mods to explain Ohms Law

The voltage and resistance will determine the current. It's ohms law. Like UberDuper said, the resistance of the atty and the voltage supplied will determine the current.

Example:
2.5 ohm is generally the resistance of 510 atty
Equation for determining current E / R = I
I=current
E=Voltage
R=Resistance

5 volt / 2.5 ohm = 2.0a
3.7 volt / 2.5 ohm = 1.5a

The current rating on a power supply is the most it's capable of producing, not how much it sends out. The amount of current is determined by the load (atty). If the voltage and resistance remains constant, it wouldn't matter if you hooked up a 10 amp power supply it will always draw the same amount of current.

If you look at the data above the amps used when the battery is loaded is at 2.97amps the 510's resistance is at 2.1 using ohms law R(I)=E so that would mean that the working Voltage was @ 6.237v but then when batt loaded voltage was measured it was at 5.18V.

Secondly battery specs says Maximum discharging rate:< 550 mA so how come the reading is @ 2.97amps 8-o 8-o do I need a better multimeter

 

[tonyfalkon]

Here is the AW 18650 High Drain Battery

AW P18650 - 26 SPECIFICATIONS:

Constant Voltage : 3.7V
Capacity : 2600mAH ( rated at 0.2C discharge 4.2V - 2.8V @ 25℃ )
Operating Temp. : Charge 0 to 45℃ / Discharge -20 to 60 ℃
Max. Charge Rate : 2.6A ( ambient temp. 25 ℃ )
Max. Discharge Rate : 5.2A ( ambient temp. 25 ℃ )
Dimensions :18.52 X 68.16mm ( +/- 0.3mm )

Fresh from the charger

510 loaded voltage

510 amp draw

cartomizer resistance

808 amp draw

808 aw loaded voltage

 

[BuzzKill]

After performing this experiment I had more questions than answers, are we really vaping 6v or 5v, I have no background in electronics and most of the people I asked about voltages always refer me to ohms law.

This a quote by one of the mods to explain Ohms Law



If you look at the data above the amps used when the battery is loaded is at 2.97amps the 510's resistance is at 2.1 using ohms law R(I)=E so that would mean that the working Voltage was @ 6.237v but then when batt loaded voltage was measured it was at 5.18V.

Secondly battery specs says Maximum discharging rate:< 550 mA so how come the reading is @ 2.97amps 8-o 8-o do I need a better multimeter

the resistance of the atty will go down with temp. if you do the calculation using the voltage and the current it is 1.74 ohms res. @ 15.4 watts

your meter is fine

The AW battery is designed for these applications ( max current discharge rate )

 

[Rocketman]

Tony,
I'll comment on your testing which is more than a lot of folks would be interested in doing.
The quest for knowledge and all, A+.

I noticed the error trend (don't work like Mr. Ohms says) increases with increase current.
the 808 at 4v is closer to theoretical, than the 510 at 4v which is closer than the HV test of the 510. Deviation from theoretical goes up with current.

If you draw out the complete circuit of your tester consider point to point voltages through the entire circuit for each configuration. binding post to switch resistance, switch resistance, battery terminal to switch, each and every point to point voltage drop and resistance through the entire loop is based on Kirchhoff's Voltage Law. The sum of all voltage drops + and - through the circuit shall equal zero (sort of).

Sources of potential errors in your test results can be:
Increased contact resistance (several contacts) with increasing current.
Nonlinear response of meter (tolerance is usually +/- some % of scale + some % of reading + some minimum number of digits).
Tolerance shift between ohms, amps, and volt function.
Resistance changes from one measurement mode to another.
(insertion resistance of meter during current measurement will impact circuit resistance)
Second and third tests after taking the battery off charge will change results.
It would be best to simultaneously measure voltage at the atty and current in the circuit. All conditions would be instantly the same for both voltage and current.

Look the test circuit/schematic over very closely. Make some under load voltage drop measurements with meter probes around the circuit.

If you are violating either Ohms Law or Kirchhoff's Law you can get into BIG TROUBLE.

Or maybe nothing is wrong and it's just a Fluke

Rocket

 

[tonyfalkon]

Ughhhhh now I have to pick everything apart and check for contact resistance darn that kirchhoff

Wish I had a fluke , I heard great things about them

 

[tonyfalkon]

The GG 6v 801 atty resistance

2 tenergy newly charged

GG atty amp draw

GG atty resistance under a load

GG atty loaded voltage

 

[Rocketman]

Wow, I didn't know the atty resistance was that high. But I'm not up on high volt e-cig parts. And did you notice that again at a lower current (as compared to the high voltage 510) your measurements are close to theoretical?

(don't measure ohms with power in the circuit).

What would be really cool with that test set up would be to match attys

in pairs for use in a double barrel mod.

R

 

[tonyfalkon]

Yeah that would be nice matching atties for double barrel use, it would make sense to use high drain cells with that setup as well since it can handle the load better than your run of the mill Lithium Cells. Whether or not atty's resistance should be no higher than 3 ohms is I think, moot when your using high drain cells and I guess a matter of preference at that point.

 

[Ralph T]

the resistance of the atty will go down with temp.

Did you mean atty resistance goes down with an increase in temp, or that it goes down with a decrease in temp.

I decided to test it and determine which way it goes. I already had a test coil made out of 30 ga nichrome. It read 2.9 ohms at room temp. I threw a torch attachment on the butane soldering iron and ran the flame back and forth over the coil (low orange glow). The resistance jumped up to 3.2 ohms, (about 10%).

It's important to note that a properly juiced atty coil will not get anywhere near "low orange glow" during normal (while vaping) operation, so the increase wouldn't be as large. Thats because the evaporating juice and filler are dissipating the heat. Two tables on this page show that the resistance would actually go UP between 2 and 3.5% if the wire goes from 68F to 400F, depending upon the nichrome formula. 400F is probably a lot closer to normal atty temps than "low orange glow".

 

[Scottbee]

Did you mean atty resistance goes down with an increase in temp, or that it goes down with a decrease in temp.

I decided to test it and determine which way it goes. I already had a test coil made out of 30 ga nichrome. It read 2.9 ohms at room temp. I threw a torch attachment on the butane soldering iron and ran the flame back and forth over the coil (low orange glow). The resistance jumped up to 3.2 ohms, (about 10%).

It's important to note that a properly juiced atty coil will not get anywhere near "low orange glow" during normal (while vaping) operation, so the increase wouldn't be as large. Thats because the evaporating juice and filler are dissipating the heat. Two tables on this page show that the resistance would actually go UP between 2 and 3.5% if the wire goes from 68F to 400F, depending upon the nichrome formula. 400F is probably a lot closer to normal atty temps than "low orange glow".

Yup, yup, yup. The resistance as a function of coil temperature is pretty predictable and reliable if you know the specific alloy. And... if you have a rock solid voltage source and a device that can read the current at a high resolution, it's a great remote way to tell what the actual coil temperature is on your device. Basically it's resistance pyrometry.

 

[Ralph T]

Resistance changes from one measurement mode to another.
(insertion resistance of meter during current measurement will impact circuit resistance)

I am glad you are here Rocket. I had completely forgotten about the extra resistance in the meter when measuring amps. That would be in series with and add resistance to the overall load. Duh!

 

[BuzzKill]

As Scott said If you know the material you can look up the res. change . Also if you use a regulated supply lots of the issues you see there will change .

With a regulated supply the V will remain constant , I have done many tests this way and the atty resistance is ALL OVER THE PLACE , add juice Big change, over 5 sec. Big change, etc.
I monitored both the Current and Voltage in these tests , there was 1 variable the resistance , the current change with a stable voltage can only be caused by a res. change.

 

[Ralph T]

Yup, yup, yup. The resistance as a function of coil temperature is pretty predictable and reliable if you know the specific alloy. And... if you have a rock solid voltage source and a device that can read the current at a high resolution, it's a great remote way to tell what the actual coil temperature is on your device. Basically it's resistance pyrometry.

Good to get your input Scott. One of my dreams is to someday own a really nice DMM, and regulated supply. For now, it's all nickels and dimes for me. I have been playing with PWM for variable voltage control. Someday I will figure out how to squeeze that into a mod box with a couple of 18650's so that I can dial in the voltage to match what the juice + atty tastes best with.

 

[BuzzKill]

Use a cheap as dirt Lm317t regulator very easy to use High power no fuss 2 res. or 1 with a pot .

As far as the meter res. I far as I remember the res. is in the order of 0.1ohms , I just tried measuring mine ( FLuke 75 MM ) no reading BUT it could be a wrong reading

 

[Rocketman]

I don't have the time until summer or maybe September WHEN I RETIRE
but the PWM idea is a good one Ralph and RC electric motor controls do that. THere are some 4 to 5 amp controllers (I have a couple of 30 amps one) that could be adapter to atty power control, a thought, right?
and Scott, you are correct, high precision heater circuits use both temperature monitoring with an RTD and predictive control with VA power monitoring. Sort of sensing the resistance change before the temperature sensor does. Look up late at night, systems like that flying overhead.

Resolution is the key to relative measurements of Volts, Current, and ohms. Accuracy matters of course but if you ain't got the digits, you ain't got the resolution to detect change. Most smaller 3 1/2 or 4 1/2 digit meters don't have low ohm capability, have a 2 or 20 volt range, so neither of these functions are optimum for us.
A 2 amp range is pretty good for most e-cig measurement but if you have to change to a 10 or 20 amp range the meter is actually using a different shunt and readings might not compare.
Point to point loop analysis may help in pin pointing any unexpected voltage drops in your tester Ralph but the circuit variation between modes is probably the culprit.

I did some night shift measurements at a particular Rocket Factory and the alloy used in the KR808D-1 is very close to the resistance curves for NiCr 60. Don't know about others, and alloys are a plenty out there.

A variable supply per buzz is the way to go on the Cheap.
Another would be to set up a regulator for Constant Current. Switch selectable for 0.1 amp, 0.5 amp, 1 amp, 2 amps. This would produce a curve of repeatable results.
So much we could do if the stuff would could to us and we didn't have to get off our butts
(speaking for myself here, while I recline, type on the laptop, and vape, and getting nothing done).

ummmm pufff, ummmmm puffff,

Rocket

 

[Ralph T]

Use a cheap as dirt Lm317t regulator very easy to use High power no fuss 2 res. or 1 with a pot .

I assume that one was to me. I tried that. Got real hot, real quick.

The nice thing about PWM (Pulse Width Modulation) is that very little energy is wasted as heat. Whereas standard regulators seem to dissipate the heat as waste. If you have an 8 volt source and switch it on and off repeatedly, lets say 75% on, 25% off, 10 times per second, then the atty see's the equivalent of 6V. An average of 6V if you will. Very little wasted heat. The circuit isn't conducting 25% of the time. You can vary the percent "on" time of the cycle thus changing the average voltage sent to the atty.

Edit: I may have misunderstood what you meant the LM317 was for. I thought you meant for variable voltage output for a PV.

 

[tonyfalkon]

I noticed that after the experiment with the 510 titan the resistance jumped from 2.1 to 5.6 too bad I wasn't able to test the atty at 3.7 first. Any thoughts to how this happened.

 

[Ralph T]

(speaking for myself here, while I recline, type on the laptop, and vape, and getting nothing done).

ummmm pufff, ummmmm puffff,

Rocket

You got that problem too. Seems I was much more effective at getting stuff done until I stopped smoking, started vaping, and probably most detrimental of all was finding this forum.

I seem to need a couple of extra hours in my day now. Need some blinders like they put on them Budweiser Clydesdale horses too. Then maybe I could stay on task. Hmmm. Budweiser. Yep, this turned from a "better habit" to a time consuming hobby. Hmmm. Budweiser.

 

[Ralph T]

I noticed that after the experiment with the 510 titan the resistance jumped from 2.1 to 5.6 too bad I wasn't able to test the atty at 3.7 first. Any thoughts to how this happened.

Could be a poor solder joint in the atty itself. Sometimes these reveal themselves at HV. Sometimes you can even fix that with a dry-burn, or two. Was your atty wet when you did the test? About how many seconds was it cooking during the test?

There seem to have been a lot of problems with bad 510 attys lately.

 

[tonyfalkon]

I blew air in the atty before testing it was dry when I measured for resistance, when I did the burn test it was wet. I read somewhere that atties with low resistance are prone to failing when you do a dry burn, and no more than 4 seconds between each test.

Just a progress report atty died after 3 3 second hits of HV vaping. I thought these atties were tougher than this though, I chose this atty because it was an original 510 titans and not replacement atty. I still remember my first oem 901 atties, they lasted 2 months in HV vaping before they gave out. I guess it was wishful thinking to assume it was the same across the board.