A USBpass has 1/3 the current delivered by a Prodigy??? I don't understand...that doesn't seem to jive with the many other posts I've read that state that the current is virtually identical. Please explain.
It should, assuming your USB used is a PC (or Mac) USB2 port, per USB2 spec.
That spec allows for up to '5 USB load units' of 100ma each.' basically, 500mA, or .5A.
A 5v device like the Prodigy uses batteries which can deliver 4A on up.
Now, 'higher isn't better,' you just need enough for the circuit being used.
in this case, you have a fixed (ish, some variances for batteries full charge, and USB inconsistencies, under load, etc). 5vDC.
A 510 atty is ~2.5Ohms resistance.
A 801 atty is ~3.4Ohms resistance.
So, a 'pure' 510 5v device, would draw ~2Amps current,
assuming the power source can provide it. Which a PC/Mac USB2 port can not. It may provide a bit over, like .6A, but that's still a far cry from the 2A.
A wall wart USB adapter, or powerpack, may provide up to ~2A, or at least 1.5A, which is closer.
CR2s/18650 etc can all provide > 4Amps, 'more than enough for any e-cig atty today' basically..
The attys *do* seem to change resistance as heated due to the nichrome coils, but I believe it's < 10% change, so that still leaves us with :
1. I have no idea what standard ecig batteries can sustain for discharge, but I suspect not much more than a USB2 spec port.
2. USB2 isn't the same on a PC, versus wall wart vs power pack on output.
3. The more common batteries, CR2/123, 18650s etc all can output more than enough current for any attys out there today (ok, common ones, anyways).
If we go back to the 3.x vDC of e-cig batteries, for a typical 801/pen atty, it works out to roughly a draw of 1A. And, as many *prefer* a direct USB to their screw-on e-cig batteries, it seems likely that the e-cig batteries also are underpowered, from a discharge/Amperage standpoint, which may well be why some prefer a USB PT, even on a PC, to their e-cig batteries, plus the higher voltage.
We can also see that Watts is: P = I(current/Amps) x E(Volts)
So basically, increase current flow or voltage = more Watts, basically = more vapor/hotter burn, blah blah blah.
But, considering the attys we have are 'designed' to run at lower...presumably there's a tradeoff in there somewhere - increase too much and attys will pop, not from solder joints or 'crud buildup' (which is valid as well), but will burn up from the current being passed through them.
If you have a device that is able to get the amperage it requires by it's design, but want *more*...easiest alternative = increase voltage, which will in turn produce higher current, higher watts, etc.
Measuring your USB output, and atty resistance will let you plug in your own values of course, but that shouldn't change, unless you have added components, flaky grounds or contacts, etc.
But 5vDC USB2 port != 5vDC power pack != 5vDC battery or Prodigy.
Sorry for the thread derailment.
