Rocket's carto-meter

[Rocketman]

One thing that gets some of the DIY mod builders is 'other' resistance. When you measure a carto with a normal 2 lead meter that is the resistance of the meter leads themselves, and internal resistance of the meter. Back in the day of 3.4 ohm cartos, an extra 2 or 3 tenths of a ohm did not seem important.

With 1.5 or 1.6 ohm stuff now, that 2 to 3 tenths of an ohm is a lot.

So, measure the leads by shorting them out, letting the meter stabilize, and subtract that from the carto and leads together.

If you get 0.3 ohms for the leads and 1.9 for the carto and leads then the carto is 1.6.

Make sense?

One other way is to make the leads as short as possible. Or eliminate them all together

like with

Rocket's Carto-Meter

that can measure carto resistance and LOADED VOLTAGE. (Photos show 9.6 watts into a Dual Coil Carto, from a 3.7 volt box mod)

 

[TomCatt]

Cool Rocket! What'd you do, splice an atty and batt connector in to the jack leads?

 

[Rocketman]

cut a carto, used a 510 batt connector and pressed into the cut off part.
18 ga wires to runs on the circuit board for +Vin and COM right at the point the runs are jumpered from the plug board to the main board.
The connection for the carto had to stick out more to be "eGo" compatible.

 

[Brad524]

are you still able to use the leads for other projects?

 

[Rocketman]

Leads are still in the package.

meter still works (if you take the carto off )

I would sure hate to screw up a perfectly good $4 Harbor Freight meter.

 

[Rocketman]

Here's a close up of the points I soldered to.


Oh well, about the best the forum photo editor will let through

 

[TomCatt]

I repeat, once again, MacGyver has nothing on Modders! Cool work there Rocket!

 

[Sci]

Hats off to ya, Rocket! You've just given new life to a few meters I have laying around.

 

[ScroungerLee]

Very nice!

Time to search for my old meter I replaced that would no longer zero the ohms reading.

Lee

 

[icemanx3]

Wicked. Great work.

ice

 

[Uncle Screwtape]

I have a few of those cheep meters laying around, I think they were $1.99 at a HF sidewalk sale a few years ago.

I think with the help of a DPDT switch, it could measure amps while you vape as well.

Hmmmm, I need to schedule some workbench time........

Thanks for the inspiration RM, once again.

 

[Rocketman]

I kept both jacks close to the plug board to keep lead length to a minimum. You don't want to add more path resistance or you'll be back to adding lead resistance. Use heavy short wires.

Sure looks strange vaping with this contraption, but you can

 

[Rocketman]

I think with the help of a DPDT switch, it could measure amps while you vape as well.

This is the Optional Amps and Wattage Attachment I use.

I'm sure you can find instructions on how to use this attachment 'On-Line'

Any body sell a 90 degree drip tip?

 

[Uncle Screwtape]

This is the Optional Amps and Wattage Attachment I use.

I'm sure you can find instructions on how to use this attachment 'On-Line'

LOL, math hurts my brain and that's one thing duct tape can't fix.

I'm curious if current goes up/down after 2, 4, 6 seconds into a vape,,,, without doing the math

 

[Rocketman]

I sacrificed a 1.6 ohm carto in the name of science and this is what I found.
A 10 second heat:
The carto resistance went up less than 0.1 ohm to about 1.7 ohms. I used a 26650 3.7 volt mod that started at 3.91 volts and dropped to 3.90 volts. I would guess that the current went down in this case as the resistance change had more impact on current than the small change in voltage. With a less capable battery the voltage would fall more and and the current would fall even more. I'm not sure there is a case that would increase current as the carto heated, and the cell voltage dropped.
But, I didn't actually measure the current.


Often watching a digital meter for the first second or so you will see the reading, volt or amps climb (ohms will fall). I think this is just an anomaly of the meter charge integrator coming closer and closer to a final reading.

 

[Rocketman]

I'm curious if current goes up/down after 2, 4, 6 seconds into a vape

If you are interested in a mod idea where the voltage climbs as you vape (starts out low them clmbs as you hold it) then you might experiment with a circuit I've been thinking about.
I just don't do high voltage vaping and this is where this would be best. An RC network to raise voltage to an adjustable regulator. It could start out say at 4 volts set by a resistive divider, and the capacitor charge with a time constant of 5 seconds or so from the input cell voltage. A zener could set the upper charge limit. The voltage divider would discharge the cap between vapes. You could do 4 volt short vapes, or if really jonesing hold for over 5 seconds and vape as it clmbs to 5 volts. Sounds interesting, just never had the time or inclination to breadboard it.

 

[TomCatt]

Dang, Rocket, I'm amazed .

I betcha if we could get all you Super Modders and Mod Gods (you, breaktru, CraigHB, nico, asnider, etc, etc,) together on a week long retreat, you guys could come up with the ultimate mod!

 

[Rocketman]

Thanks for including me in one of those categories
But, there are some different points of view about low volts, high volts, vari-volts, circuit designs, mod shapes-big or small. All have there place, but for the masses, there is no ultimate mod. Each vaper should find his own comfort zone.

The big trick?

Is to know when you are there.

Thanks again.



I forgot to ask. Who be paying for this retreat?

 

[MadmanMacguyver]

Aww rocket now your getting it...a retreat w the other modders extraordinaire...hey if someone will pay I'll sign up for this retreat...I do actually have a bit of faith in it...oh wait...is someone supplying tools and modding material too...look out Gummy may have a bus load of modders from his clinic heading this way....ROFL.....

BTW nice retooling of the HF meter Rocket...bout the only use for em I see...they're too loosy goosey withe the readings for much else in my opinion...but then again in the case of meter or no meter...well even the HF $4 meter looks good at that point...

I cant talk much tho...I have one of their 40 dollar ones...but it is auto zeroing and reads as accurate as my neighbors 300 dollar meter so hey this I can accidentally drop it and I won't have a coronary...

 

[clutchjunkie]

You can get those meters for free, check your sunday papers and sign up for their snail mail spam. They put out coupons all the time for the meters, tape measures, flashlights, all kinds of stuff. You have to buy something to redeem, but I haven't seen a minimum purchase anywhere. Sometimes if you get to know some of the employees on a first name basis they will let you get a different freebie (a meter when you have a flashlight coupon, for example) if you ask nice.