How does one setup and use a multimeter?

[Skeeter T]

Okay...I think I figured it out. To test your mod under load, you buy something like this... 510 Voltage Indicator and screw it on your mod then hit the button...it should read the volts it getting. And I can't tell from the pictures, but it looks like there is an atty connector on the other end that can be used to test the mod with the atty on it...under load. Make sense?

I think Mad Vapes and COV and places like that also have these available. I just remembered seeing this one while surfing his site last night.

Well Rhasps, ya tried. Now I'm not an electronics engineer by any stretch of the imagination, but I would guess the output voltage of a 3.7v batt under load would be around 3.7v, and I would also guess the amperage is the variable under load. From what I've recently readl while looking for some IMR 14500's in stock (good luck) is that they put out significantly less amps than the IMR 18650's, which means ... I have no idea what I'm talking about, but it sure sounded good for a while. Right? We need someone that knows this stuff to explain it and I think Fluke 175 (BardicDruid) is the one. He's already over my head. What's the diff between RMS and True RMS, (Root Mean Square)?

Ted

 

[Rhapsodies Fire]

Some REOnauti have done a test...as far as the metal mods go...when you use a fully charged 3.7v battery which meters at 4.2ish, in the mod...it meters at about 3.8 - 3.9 ish under load...due to the resistance of the mod and the atomizer.

Edit...so I haven't finished watching the video, insanely slow wifi ...but I can tell already that I need to note that the tests I was referring to were done on metal mods.

 

[Mudflap]

This might be of interest to some folks reading this thread:

 

[Rhapsodies Fire]

Thanks, Tripp!

 

[Skeeter T]

So, the amp draw of a fully charged batt that is putting out 3.9v under load using a 1.5 ohm atty according to Ohms Law (nobody argues with Mr Ohm) would be I (amps) = V (volts) / (R) resistance or 3.9 Volts divided by 1.5 Ohms = 2.6 Amps, and using an identical fully charged batt with a 2.3 Ohm atty would be 1.7 Amps.

I would then guess the life of the batt using the 2.3 atty would be 2.6A / 1.7A minus 1 = 53% longer than the life of the batt using a 1.5 atty (with all other things being equal ... draw time, rest time, draw amount, temperature, etc.). If my figures are correct, which I wouldn't bet on it, then that's really significant. Always remember, figures don't lie, but liars do figure.

 

[stretchpants]

Marking for the info.

 

[Gristle]

Does the internal resistance of DMM's usually have to be subtracted from the actual atty reading or are they self compensating?

Some are self compensating, others should be zeroed. You zero by touching the leads together and adjusting the meter to make this the zero point.

Also, how do you measure the mA and/or mAh of a batt under load?

Ted

Amperes for DC need to be measured with a serial connection of the meter between the battery and atty/carto. This is very hard to impossible for PV's without a custom fixture. The other solution would be to measure the resistance and voltage and then calculate the amp draw. I don't know of anyway to measure Mah (capacity) of a battery.