5v passthru on PC

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markfm

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A typical dc carto is rated as 1.5 or 1.6 ohms. They really should not be used on a straight passthrough (one without an inline battery or regulator) connected to a pc.

Usb is 5v nominal. That is over 3 amps for a 1.6 ohm carto.

Even with a good dedicated 2a usb power supply, you should not go below 2.5 ohms, or you are over-driving the supply.
 
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markfm

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Dc is dual coil, two heating elements in parallel.

2.2 is too low for either, trIes to pull too much current at usb voltage. Either usb port failure or early power supply failure may occur.

True pt really should be avoided on a pc, use a dedicated power supply. $10 ps removes the possibility of toasting your pc.
 

eko824

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Dc is dual coil, two heating elements in parallel.

2.2 is too low for either, trIes to pull too much current at usb voltage. Either usb port failure or early power supply failure may occur.

True pt really should be avoided on a pc, use a dedicated power supply. $10 ps removes the possibility of toasting your pc.

So what cartos do you recommend using with this pass through? I just ordered a Vap-o-matic Liquinator with LR cartos. I'm assuming that would be a no go with this PT?
 

zerominusone

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I heard it was kinda dangerous to plug a passthru directly into your pc's USB port. The passthru could possibly fry the port, thereby harming your pc. To eleviate this, I bough a powered USB hub and us that for my passthru when I'm at my computer and I got a 5v USB wall converter for <$10 that I plug into the wall near my chair while I'm watchin' the toob.
 

briDog

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I got my 2a-5v tekkeon usb power pack and tested with both lr and sr boge cartomizers and it makes a huge difference. As markfm stated I'd not recommend using lr or anything below 2.5 ohm if using with tekkeon power pack as it burns the juice too quickly and overpowers the taste and it may damage the power source or carto, however using the pc would not harm it, imo. LR feels weak on pc but gives good vapor after several puffs. My sr boge cartos varies from 3-3.4 ohms and so far 3 ohm gives the best for both vapor and th, and it feels definitely above 3.7v but not quite 5v.
 

markfm

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The reasons not to use the PC USB are twofold. First there is the potential for a flat out short circuit -- atties do go bad sometimes, wires get loose. Even on a good USB design this should blow the USB fusing mechanism, and if it doesn't you have potential knock-on effects taking out electronics and/or PC power supply.

The second is that even if you don't have a short, you may significantly over-drive things within the PC. The USB spec calls for 500 mA drive capacity on a USB port. Although a given port may indeed have enough oomph to handle 1.5A, or even 2A, draw, there's no guaranty, and you may be overdriving the electronics (USB controller, power supply,...) into early failure.

Sometimes you'll try something and it "works", but it turns out to not be quite as warm/powerful as expected precisely because you are seeing a voltage sag off of the PC -- there isn't enough oomph in the system to handle the demand, and that nominal 5V is dropping to, say, 4V. That is not a healthy operating state for the power supply.

Replacing/repairing any PC component is going to cost more than the $10 of a dedicated 2A USB supply.

(The techie side of PVs is interesting to me as an engineer. On the other hand it can cause confusion for people who think that as long as it is a USB connector it should be okay to plug into any USB port.)
 
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