will a 4.5V/1600mA AC-to-DC Power Adapter work for a 510 PT?

[oldsoldier]

Hi guys,
I'm wanting to build a PT for a standard 510. I've decided to go to a plug in the wall (well actually my powerstrip) rather than plug into the computer USB port.

If I get a 4.5V/1600mA AC-to-DC Power Adapter for a couple bucks and hard wire it into a project box like the madvapes 501 kit, will it work? or is 1600mA too hot?

Edit: since no one has answered as of yet I'll go a step farther. I went to an online ohms law calculator and entered 4.5V/1600 mA and find that this works out to 2.8125 ohms. Assuming that a standard 510 atty should be in the range of 2.2-2.4 ohms I'm guessing that this should work without instantly popping an atty? I'm not smart on the math and theory, so if anyone out there can double check me and make sure i'm understanding this correctly I would appreciate it!

 

[mdocod]

I'd say there is a good chance of success... Here are some considerations though:

If this is a standard transformer style AC-DC adapter (I like to call them "wall-warts") then the actual voltage will vary with load. It's not uncommon for the open circuit voltage to read 50% higher than the rated voltage. As a load is introduced, the voltage drops down to a balancing point depending on the load presented. In your application, with the expected ~2.3 Ohm load, the exact resulting behavior will depend on how much overhead current the transformer in question can actually deliver. More than likely what will happen is the voltage will sag below the 4.5V rated since the transformer can not produce enough current to hold 4.5V into a 2.3 ohm load. I suspect that what will happen is, the transformer will sag to around 3.5-4V range and drive the atty fairly close to the intended drive level (well, maybe overdriven a hair). Many transformer style power supplies you find in home electronics are purposely wound to prevent them from delivering above their maximum current rating (regardless of load), or might have a ~10-20% overhead at best. If this is the case with the power supply you are using, then everything should work fine and you can just plan on driving your atty at ~1.6A, the voltage will sag to match the maximum current that can be supplied.

If the power supply you are talking about here is a regulated or switched supply of sorts, then it's very possible that you may wind up killing the power supply or the atty. Many regulated power supply designs will try to hold that 4.5V regardless and self-destruct when presented with loads beyond their ability. It's possible that it may be able to hold close to 4.5V for a few seconds at a time without self destructing which could lead to premature atty failure. More sophisticated power supplies often have temporary lock-outs that prevent excess current from continuing to flow (forcing a power down and restart).

I am going to have to research this USB pass-through thing, I have always been under the impression that most USB buses don't support more than ~500mA. Seems like a major lack of power to me...

Eric

 

[Drozd]

1600 mA isn't too hot...in fact it may not be enough..

I always red specks like that as 4.5V or 1600mA just different ways of expressing output...

anyway if you work the whole Ohms law from another angle... and figure that a 2.2Ω atty at 3.7V has an amp draw of 1.68A.... well that's 1680mA
so that power adapter would be working at full output and you'd still be getting slightly less than a 3.7V vape...

that's part of the reason why most 3.7V 510 PTs have that inline battery box because the usp charges the battery and it runs off the battery...
and people using 5V PTs often have trouble running off some USB ports and have to get at least a 2A output adapter (and even then they aren't running at 5V (2.2Ω resistance at 5V is 2.27A)

so I'd say yeah it'd work for running a standard 510 atty at about the rough equivalent to 3.5V so somewhere in between a stock 510 battery and a 3.7V battery...

then again cheap *fire 14500 batteries are only capable of delivering 1.3A anyway so you'd be getting less sag with that adapter than running a regular Li-Ion...

if it were me I'd probably look at finding some board to put into the box and make it rechargeable via USB (like a bartleby) and run a high drain battery in it so it works as a PT only in the sense that you keep it plugged in to keep charging the battery as you vape from it...

hmmm.... that makes me wonder if something like an eGo fast charger could be taken apart and the board wired into the box to charge a battery and take a mini USB input...should be possible

 

[WillyB]

then again cheap *fire 14500 batteries are only capable of delivering 1.3A anyway so you'd be getting less sag with that adapter than running a regular Li-Ion...

That's not true at all. That would mean that all the folks using 14500 box mods with standard cells and Joye atties are vaping at 2.7V. That's hardly the case. The first thing folks notice when moving from standard 510 ecig batts to their first 14500 box mod is the increase in performance, not an unvapable 2.7V.

 

[o4_srt]

That's not true at all. That would mean that all the folks using 14500 box mods with standard cells and Joye atties are vaping at 2.7V. That's hardly the case. The first thing folks notice when moving from standard 510 ecig batts to their first 14500 box mod is the increase in performance, not an unvapable 2.7V.

if I remember correctly, that is what they are rated at. They will actually provide more current, but it is pushing the capabilities of the battery.

To reduce voltage sag, why not incorporate a large bypass cap? I made a car adapter box for my mod, using an LM317 that I pushed to its limits. It created quite a bit of heat, so I added a 40mm fan to the adapter box. When vaping, i noticed the fan speed was significantly reduced when the atty fired. I added a 2200 uF bypass cap to the setup, and now the fan speed does not change when the atty is firing.

 

[four2109]

will a 4.5V/1600mA AC-to-DC Power Adapter work for a 510 PT?

Yes, RS had them last year back, cheap. I like it better than 5V.

 

[Drozd]

That's not true at all. That would mean that all the folks using 14500 box mods with standard cells and Joye atties are vaping at 2.7V. That's hardly the case. The first thing folks notice when moving from standard 510 ecig batts to their first 14500 box mod is the increase in performance, not an unvapable 2.7V.

max drain rate is mAh rating in A times the C rating.....

so .900A * 1.5C = 1.35A max drain

thats a 900 mAh ultrafire which according to specs has a 1.5C rate...

 

[mycro]

its what i use-not for a 510 but i have a couple set ups like what u r saying (for an 801, and kr808 type, which i also use with 901 attys)

 

[mdocod]

max drain rate is mAh rating in A times the C rating.....

so .900A * 1.5C = 1.35A max drain

thats a 900 mAh ultrafire which according to specs has a 1.5C rate...

"C" ratings are a function of time and really shouldn't be calculated from exaggerated label capacities. If a cell is rated for 1.5C discharge rates, that that basically means that the load should not drain the less in less than 40 minutes of operation. Many cells are rated 2C, that means that the load they are connected to should not drain them in less than 30 minutes.

In other words... If the true capacity of the cell is more like 700mAH at a 0.1C rate, and 600mAH at a 1C rate, then it would be accurate to assume that the maximum ideal discharge rate for the cell is actually less than 1 amp. This does not mean that the cell can not deliver more current than this, it just means that it's best NOT to draw more current than this if you want the cell to live a healthy safe life.

*most ecigs draw more current from LiCo cells than the cells are rated for, until you get up into larger format cells, like 17500 and larger*

The approximate amount of current that a typical 14500 LiCo cell can deliver over the load of a particular atty can be calculated pretty easily. Just figure out the total circuit resistance including the cell and work from there....

A typical 14500 size cell with a protection circuit can easily account for ~300mOhm resistance. Assume that the atty is 2.3 Ohm and there is 0.1 Ohm of resistance in the various connections and contacts in the circuit. The total circuit is ~2.7 Ohm.

4.2V/2.7Ohm=~1.55A, ~5.5W to atty
3.6V/2.7Ohm=~1.33A, ~4.1W to atty

For a low resistance atty, the resistance expected at the cell and connections all stays the same... just the atty changes. 1.8Ohm atty + 0.3Ohm cell + 0.1Ohm = 2.2Ohm

4.2V/2.2Ohm=~1.91A, ~6.6W to atty
3.6V/2.2Ohm=~1.64A, ~4.8W to atty

That's about the range that could be expected. As the cell ages, the resistance will rise, and the performance will diminish.

That's probably in excess of a 2C rate. However, since ecigs are used in short bursts, it's not as big a problem.

Eric