The Multi-Meter is my Friend

[breaktru]

Assuming you have a decent Multi-Meter and you know how to properly use it,
measure your atty/carto resistance, attach atty/carto and measure voltage and current draw.

DON'T rely on Ohm's Law. You're calculations will be way off compared to what you are actually getting.

Current and Wattage is subjected to your regulator and battery limitations.

I've made these comparisons between actual measurements and ohm's law with the 08100w w/ two batts in series and w/ different batt models and mah's.
Also w/ the 04050c w/ 1 batt and w/ two batts in parallel and w/ different batt models and mah's.

 

[skinnee]

Good advice... I always keep my Fluke handy next to my vape Station.

 

[breaktru]

Handy Multi-Meter accessories:

Attach atty/carto to top, screw bottom into PV, attach amp probes to protruding studs, place meter on amperage 10A taking note of polarity. Neg to bottom, Pos to top stud. Meter will shunt to complete circuit.

Place atty/carto on top and screw bottom into PV.

 

[jhonutz]

from my experiment at 2 ohmi and 3.8V curent draw is about 900 ma, at 2.5ohmi and 4V about 1.2 A.

 

[breaktru]

I would like to play a little game here..........

With Ohm's Law, calculate what you believe your Amperage and Wattage is
then take actual measurements and post both results here...

Measure your atty or carto for actual resistance and your voltage output w/ the atty/carto attached.
Use the Amperage = Voltage x Resistance
the Wattage = Voltage x Amperage
Then compare to actual measured Amperage and find Watts as described above.

 

[TomCatt]

<<bookmark to do this tomorrow>>

 

[Antoly]

Carto resistance - 3 Ohm

Battery voltage (not connected to atty) - 3.9 V
Actual measured Amperage - 1.25A
Amperage predicted with Ohm's law - 1.3 A

Another measurement when battery's voltage dropped a little

Battery voltage (not connected to atty) - 3.86 V
Actual measured Amperage - 1.23A
Amperage with Ohm's law - 1.29 A

Considering that a battery always has its own internal resistance, which we should add to the coil's resistance but which we can't measure, Ohm's law just works. So it's better to say not "Don't rely on Ohm's Law" but "Don't rely on your multimeter". Especially when "2 ohmi and 3.8V curent draw is about 900 ma"

 

[Rocketman]

here's another little test.

Put your meter on the 10Amp range and hook up the leads you normally use to measure amps.

Now, take another ohmmeter and measure the resistance of the leads and amp meter.

When you hook up an atty/carto directly to an e-cig, then hook it up through leads and a meter shunt to measure amps, does the battery see the same path resistance? Or is the path resistance just a little higher? maybe 0.2 ohms higher?
That could mess up calculations just a little, especially if you are talking a couple tenths of a ohm with a 1.5 ohm atty.\


When you gets results that seem to disprove ohms law, something has been forgotten.

 

[breaktru]

here's another little test.

Put your meter on the 10Amp range and hook up the leads you normally use to measure amps.

Now, take another ohmmeter and measure the resistance of the leads and amp meter.

When you hook up an atty/carto directly to an e-cig, then hook it up through leads and a meter shunt to measure amps, does the battery see the same path resistance? Or is the path resistance just a little higher? maybe 0.2 ohms higher?
That could mess up calculations just a little, especially if you are talking a couple tenths of a ohm with a 1.5 ohm atty.\


When you gets results that seem to disprove ohms law, something has been forgotten.

Rocket, I find a big difference in results using regulators/converters and not much difference using a PV w/ just a battery, switch, atty.

Also Rocket, when using the amp meter you are putting all of the circuit in to the picture. The battery, batt spring, wiring, P.B. switch, on/off switch, battery connector to atty, regulator/converter, etc... etc...

So Rocket, what was your measured results? Maybe my two amp meters are inaccurate. That is very possible.

 

[breaktru]

Carto resistance - 3 Ohm

Battery voltage (not connected to atty) - 3.9 V
Actual measured Amperage - 1.25A
Amperage predicted with Ohm's law - 1.3 A

Another measurement when battery's voltage dropped a little

Battery voltage (not connected to atty) - 3.86 V
Actual measured Amperage - 1.23A
Amperage with Ohm's law - 1.29 A

Considering that a battery always has its own internal resistance, which we should add to the coil's resistance but which we can't measure, Ohm's law just works. So it's better to say not "Don't rely on Ohm's Law" but "Don't rely on your multimeter". Especially when "2 ohmi and 3.8V curent draw is about 900 ma"

What type of PV did you get your readings from? Was it a regulated PV? or just a battery PV.

 

[Antoly]

Multimeter is intended to measure either DC or AC. Pulse width modulation used in VV is not DC and not AC. That's why voltage measurements of PWM are VERY approximate.

 

[CapeCAD]

Multimeter is intended to measure either DC or AC. Pulse width modulation used in VV is not DC and not AC. That's why voltage measurements of PWM are VERY approximate.

On the contrary PWM is used to generate the DC output. Most VV converters are DC output.