If you use a USB PassThru, u may like this

[friskyweasel]

... under load means hooked up firing an atty. Unless you have a testing harness, your readings are not accurate. You can easily expect a 1 volt drop when an atty is fired, and this is straight off a battery.

ahh..i stand corrected - apologies to aphlaque_duck - i was testing the passthru's output without an atty attached

so in short, even though it's working pretty good for me right now with the 15 ft. USB extension cable plugged into a regular pc's usb port, i could be getting much,much better performance by using a higher amperage USB wall charger...i'm definitely gonna do that!

 

[aphlaque_duck]

Just compare on the same port with and without the extension. If you can't tell a difference then don't sweat it.

 

[Switched]

True, but that loss is actually from the internal impedance of the battery - which is not regulated and is being pushed beyond spec in most e-cigs. It's similar in principle to a long cable, except that the resistance is in the source. With a reasonable cable length, the PT has an advantage since the USB supply is regulated - the port will continue putting out 5V all the way up to its max current rating.

Never thought of it that way, but yeah it makes sense. the computer power supply is acting like a governor, providing a constant 5V output.

 

[Switched]

ahh..i stand corrected - apologies to aphlaque_duck - i was testing the passthru's output without an atty attached

so in short, even though it's working pretty good for me right now with the 15 ft. USB extension cable plugged into a regular pc's usb port, i could be getting much,much better performance by using a higher amperage USB wall charger...i'm definitely gonna do that!

There is a couple of things you are not seeing here (not your fault, we all went through it), we were duped by the Chinese.

The PT was developed to extend battery life of our ecigs, which at one point was somewhere in the vicinity of 45min to 1.5hrs. So why vape on a battery when you had a power supply available (the PC). The first ones that came out had an in line battery (a good thing) <---- it protected the PC and acted like a fuse. The USB power supply was merely keeping the in line battery charged. Because you were vaping off the battery, you were vaping at 3.7V and not 5V which was available at the port.

Then came along the "direct" PT (no in line battery), folks thought they were vaping 5V. In principle yes, but the current delivered to the atty was only 0.5A or 500mA. The JoyE direct PT requires 1.5A to fire properly with a stock atty, although there was a noticeable difference (when vaping of the USB port) it paled in comparison when used off a USB wall charger putting out 2A or 2000mA, at 5V. If you are looking for battery longevity of your devices, then by all means use a PT. On the other hand if you want to vape at 5 volts, the only way to accomplish that with a PT is, having it powered by a 5V 2A wall socket or a USB hub that will put out 2A.

 

[aphlaque_duck]

Switched - that is a good point. Many (most?) PTs are actually full-time battery chargers and the power to the atty actually comes from the battery. That a good thing to do in terms of protecting the PC's USB port, instead of possibly drawing more power than it's rated for.

Other PTs are just a switch wired straight off the USB port, which is more the scenario I was thinking of in terms of wire resistance possibly making any difference.

In fact if the OP's PT is the "battery backed" type, he would probably see no difference at all from the extension simply because it is the battery taking the heavy load, not the charging cable.

I have commented in other threads on PT engineering issues. I think the products available right now are really crap for a variety of reasons. IMHO a proper PT should be battery-backed AND regulated but to my knowledge this has not been done yet.

 

[Switched]

*SNIP

I have commented in other threads on PT engineering issues. I think the products available right now are really crap for a variety of reasons. IMHO a proper PT should be battery-backed AND regulated but to my knowledge this has not been done yet.

I support the in line models as well.

Now if you are talking about a 5V cell, that is not about to happen any tine soon as max for a LI Ion chemistry is 3.7V, unless you start stacking batts, and I am not prepared to plug that set up in my PC.

My JoyE direct 510 PT performs just well out of my USB port, when used for it's intended purpose. Is there a difference when I plug it into the wall on the couch? Night and day. But I prefer the 801 on the couch.

 

[aphlaque_duck]

I support the in line models as well.

Now if you are talking about a 5V cell, that is not about to happen any tine soon as max for a LI Ion chemistry is 3.7V, unless you start stacking batts, and I am not prepared to plug that set up in my PC.

My idea is to use a single large cell with an off-the-shelf USB charge controller IC that can pass through a lot of current from the cell. Then use a boost switcher to take that up to say 9VDC, and then use PWM to drive a programmable output voltage. Then you could give it an extra "turbo" pulse at the start of the cycle to light up the atty faster.

 

[Sar]

There is a couple of things you are not seeing here (not your fault, we all went through it), we were duped by the Chinese.

The PT was developed to extend battery life of our ecigs, which at one point was somewhere in the vicinity of 45min to 1.5hrs. So why vape on a battery when you had a power supply available (the PC). The first ones that came out had an in line battery (a good thing) <---- it protected the PC and acted like a fuse. The USB power supply was merely keeping the in line battery charged. Because you were vaping off the battery, you were vaping at 3.7V and not 5V which was available at the port.

Then came along the "direct" PT (no in line battery), folks thought they were vaping 5V. In principle yes, but the current delivered to the atty was only 0.5A or 500mA. The JoyE direct PT requires 1.5A to fire properly with a stock atty, although there was a noticeable difference (when vaping of the USB port) it paled in comparison when used off a USB wall charger putting out 2A or 2000mA, at 5V. If you are looking for battery longevity of your devices, then by all means use a PT. On the other hand if you want to vape at 5 volts, the only way to accomplish that with a PT is, having it powered by a 5V 2A wall socket or a USB hub that will put out 2A.

This is a great summary. But if the passthrough has inline battery doesn't it mean that the battery is constantly recharging? Battery lifetime would normally allow only for few hundred (?) charges. Wouldn't constant charging kill the battery very fast?

 

[Switched]

This is a great summary. But if the passthrough has inline battery doesn't it mean that the battery is constantly recharging? Battery lifetime would normally allow only for few hundred (?) charges. Wouldn't constant charging kill the battery very fast?

Not particularly, LI Ion chemistry has no memory and the PCB of the batt prevents overcharging. Once the chemistry is spent, it is spent.

 

[friskyweasel]

thanks aphlaque_duck and switched for the great explanations and info...that's why this forum is the only one i bother going to for e-cig related info!

 

[o4_srt]

My idea is to use a single large cell with an off-the-shelf USB charge controller IC that can pass through a lot of current from the cell. Then use a boost switcher to take that up to say 9VDC, and then use PWM to drive a programmable output voltage. Then you could give it an extra "turbo" pulse at the start of the cycle to light up the atty faster.

whoa whoa whoa...PWM???

how do you plan to accomplish this? my next mod (after the variable voltage I'm designing now) is going to feature PWM, it'd be great if 50% duty cycle could properly fire an atty, double battery life!

 

[aphlaque_duck]

whoa whoa whoa...PWM???

how do you plan to accomplish this? my next mod (after the variable voltage I'm designing now) is going to feature PWM, it'd be great if 50% duty cycle could properly fire an atty, double battery life!

Lots of ways to do it, a microcontroller and mosfet is all you need. This is as simple as it gets really, all you're doing is heating up a resistor.

There is not likely to be a savings in battery life - you still need to deliver the right amount of power to light it, but by controlling the profile (higher power at first, then taper off) you should be able to light the atty up faster and get a better vape.