Will this work? (passthrough)

[modeezy]

I recently made a USB passthrough but every USB device I have feels like it doesn't provide nearly as much power as my 901 battery does. (multiple pc's, comcast dvr, even went as far as splicing a molex and trying to connect that way) I get 5v+ out of every device I test with a multimeter, but I think maybe the amps is what causes it to not provide much.

ht tp://w ww.radioshack.com/product/index.jsp?productId=2049707
(remove spaces between tt and www)
4.5V/1600mA AC-to-DC Power Adapter


Will this work good or is there too much mA?

[Kewtsquirrel]

I recently made a USB passthrough but every USB device I have feels like it doesn't provide nearly as much power as my 901 battery does. (multiple pc's, comcast dvr, even went as far as splicing a molex and trying to connect that way) I get 5v+ out of every device I test with a multimeter, but I think maybe the amps is what causes it to not provide much.

ht tp://w ww.radioshack.com/product/index.jsp?productId=2049707
(remove spaces between tt and www)
4.5V/1600mA AC-to-DC Power Adapter


Will this work good or is there too much mA?

Thats 7.2watts, which is a bit high, throw a couple diodes or resistors in there and try to get it a bit lower.

[modeezy]

Thats 7.2watts, which is a bit high, throw a couple diodes or resistors in there and try to get it a bit lower.

Thanks for the reply! Any recommendation of what OHM of resistor I would need?

[Laredo7mm]

Thats 7.2watts, which is a bit high, throw a couple diodes or resistors in there and try to get it a bit lower.

How does that work? Even a 3.3 ohm atty at 4.5 volts will only pull 1.36 amps. Most atty's seem to be around 3.7 ohms which will draw even less current. Just because the power supply is capable of putting out 1.6 amps doesn't mean that it will run the atty at 1.6 amps. Your logic is like saying that if you turn on your 100W light bulb that it is going blow your circuit breaker because it is going to try to draw all of your 150 service amps.

modeezy - That power supply is what I use for a plug in. No resistors needed. It works great. Just wire it up, plug it in, and vape away.

[Kewtsquirrel]

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[Laredo7mm]

Lets start out with some known values first, and work from there:
Wattage can be calculating using the formula W=VI, V is voltage, I is current (in amps)

First, your standard DSE901 battery. At peak (We always want to use peak numbers) you're looking at roughly 4.2v and 150mA, which means your output is roughly .67watts

Now, we know that 901's can be safely run at much higher power levels, Magnum mods that run on unprotected CR2 batteries sit at roughly 6.5v/.9A, which means the wattage output is roughly 5.85W at peak.

However, some users have reported a burnt taste at this level, and claim the sweetspot is around 4.5v/.9A, or 4.05W.

The USB wallwart that you would like to use is outputting 4.5v/1.6A, or 7.2W, thats quite a bit of power so lets see what we can do to get that down.

We want to reduce your total wattage by a value of 3, and since we know the amperage level, we can deduce from this the desired current drop.
If W=VI, and both W and I are known, we must simply solve for V. So V = W/I, or V = 3/1.6. This gives us a current drop of 1.875V, now we can plug this back into our original equation and check the wattage output.
W=(4.5-1.875)*1.6

This would give us a 4.2 watt output @ 2.6v/1.6a, perfect! Now we just need to figure out how the hell we can drop the voltage by 1.875v!

When it comes to resistors, and dropping voltage, I'm not your guy, but you should be able to use a potentiometer to do this, just keep adjusting it until your output voltage is 2.6v or so.

More bad info. If you feed an atomizer, that has 3.7 ohms resistance, 2.6 volts, how is that going to draw 1.6 amps?

[Kewtsquirrel]

I'm not following, maybe you can explain it better, this is my first stab at dropping the voltage on something like this to not burn an atty.

How is the atomizer "drawing" anything? The power supply is outputting 4.5v @ 1.6amps, you're wiring that directly to the atomizer, how would it *not* receive 4.5V @ 1.6amps?

[Laredo7mm]

modeezy - I think it is your best interest not to follow any of Nerf's advice.

[Kewtsquirrel]

modeezy - I think it is your best interest not to follow any of Nerf's advice.

Your advice has been pretty amazing, I bet modeezy knows exactly what to do now.

Nice explanation, btw.

[Laredo7mm]

I'm not following, maybe you can explain it better, this is my first stab at dropping the voltage on something like this to not burn an atty.

How is the atomizer "drawing" anything? The power supply is outputting 4.5v @ 1.6amps, you're wiring that directly to the atomizer, how would it *not* receive 4.5V @ 1.6amps?

Because that is not how electronics work. If this is your first try at dropping voltage then why are you giving advice?

The atty does draw current when voltage is passed through it. The atomizer is noting but a resistor. What happens to resistors when you pass voltage through them? They put a load on the system. Load is current.

Ohms law. V=IR. I=V/R. If V = 4.5 and R = 3.7, then I = 1.216 amps.

Just because the power supply has the capacity to put out 1.6 amps, does not mean that is what is going to be used by the atomizer.