5v Passthrough vs LR Atties

[Nobodyatall]

Ok i think im confusing myself. This isn't adding up. Is there something I'm missing? Is the 950 mah not part of the calculation? Someone clue me in.

Try working it "backwards" starting with amperage (since that is usually the limiting factor).

If you have a limit of 950ma thru a 3 ohm resistance, it will drop 2.85V and dissipate 2.70W as heat. If you throw 5V on it, your battery is liable to become quite cross.

If you have alimit of 2A thru a 3 ohm resistance, it will drop 6V and dissipate 12W as heat, providing you fed it 6V to begin with.

A battery as used in an e-cig is pretty much a "constant current" power supply when used @ max output. Consider the current limitations first.

 

[WillyB]

So, since the USB port has a current of .5 amps

Without some meter measurement you have no idea what the port is providing so any 'math' is based on a guess or anecdotal evidence. Math (and Ohm's Law) does tell me that .5A will not fire any atty... period.

And a regular atty at 3 ohms on a 950 mah battery is pulling 2.7v, right?

Don't confuse mA, current, with mAh the battery's capacity. 950mAh will determine how long the battery will last. If it's a 3.7V battery that's pretty close to what you'll get. Chinese e-cig makers have chosen to cut the actual voltage available. A DSE 905 is about 3.45V, Joye products about 3.2V.

The only volts that matter are those we vape at (loaded).

Trying to make some comparisons (your original post) is good, but if the '5V' is really 4.2V or 4V for others, the watts generated will be all different as will the heat and throat hit.

 

[sgtdisturbed47]

I'm starting to think there must be some sort of battery or converter in the handle where the button is. USB 2.0 has a limit of 500ma, and yet the atty is firing with 1.5 amps or so. Also, I have a 500ma USB charger that says 500ma on the specs on the sticker, and yet it's able to power the passthrough no problem.

Also, as willyb has mentioned on a PM, at 2 amps, his PT measured less than 5v with one of his atties when it should have read more than 5v. Something in the handle is allowing this PT to be powered by a 500ma charger, a 500ma USB port, and yet prevents higher than 5v operation. Is there a battery or converter in the handle? It doesn't say in the details on vaporkings web site.

 

[Rothman]

Maybe I'm the only psycho here but, I sometimes use an LR on my 5v PT. It rocks. I haven't burnt one up yet. Honestly, in my 7 months of vaping I have never destroyed an atty. Still have the original 510 attys I got with my first kit.

 

[WillyB]

I'm starting to think there must be some sort of battery or converter in the handle where the button is. USB 2.0 has a limit of 500ma, and yet the atty is firing with 1.5 amps or so...

Well you are thinking right. There is the USB charging spec.

This is supposed to allow a computer port the deliver up to 1500mA. Shorting the DATA lines tells the computer it's not a typical USB peripheral.

 

[WillyB]

Maybe I'm the only psycho here but, I sometimes use an LR on my 5v PT. It rocks. I haven't burnt one up yet. Honestly, in my 7 months of vaping I have never destroyed an atty. Still have the original 510 attys I got with my first kit.

The whole point was to determine if in fact all the folks who toss out random my '5V PT' are actually vaping at 5V. Most are not. Joye 510 users, probably none, unless they've bought a power supply that can provide a minimum of 5V@2.5A. You now will have a true '5V PT' for any normal atty made. But hook up a 1.5Ω LR atty to this 2.5A powered device and you now have a '3.75V PT'.

To be actually vaping a 1.5Ω LR atty at 5V means you would need to be supplying 3.3A (3300mA) of current. Unless you have one hell of a power supply, which I doubt, you aren't even close to 5V with your '5V PT' and LR atty.

 

[sgtdisturbed47]

Rothman said above that he uses a LR atty on his PT, he must be using a 2a power adapter since using it on a PC USB port, it wouldn't fire (2.25v). Mine sure doesn't.

I figured that there must be some sort of higher amp rating than the 500ma with USB. Shorting the data lines makes sense because if there is data transfer and the current is higher than 500ma, Windows throws an error. Thanks willyb for sharing the pinout.

Having a current of 1.5a makes sense. With a 1.5a current going through my 3Ω atty, that gives me 4.5v at the atty. It's certainly not 5v, but pretty close.

 

[WillyB]

... Having a current of 1.5a makes sense. With a 1.5a current going through my 3Ω atty, that gives me 4.5v at the atty. It's certainly not 5v, but pretty close.

Close, kinda. If we look at the watts generated, 5V is 25% higher than 4.5V. That's significant and quite noticeably hotter/harsher with more throat hit.

 

[sgtdisturbed47]

Close, kinda. If we look at the watts generated, 5V is 25% higher than 4.5V. That's significant and quite noticeably hotter/harsher with more throat hit.

I see what you mean. I'm not sure if I'd want that extra 25% though lol it seems just about right for me as-is.