Johnatl

I am wanting to make my own USB pass thru.
A USB port supplies 5.12v +- volts. can anyone tell me what resister or diode is needed to drop the 5.12v to 3.6v? in series or parralel?

Thanks...

firhill

Here ya go.....this will give all the answers you need on any type of battery mod.

Rocketman

USB pass-thru seems really handy. The USB spec provides 5 volts at 500ma per port. Adapting this to power an e-cig looks cool but are you prepared for the risks?
The normal desktop computer has a surface mount fuse on the mother board for each port. If your desktop has PCI slots then a cheap $7 card can be used to provide USB power for everything from fake little aqariums, lights, fan, just about anything. Each time one of the fuses blow, just use another port. When they are all dead, put in another $7 card. If it's a company computer you can use the factory USB ports, just call the IT guys and tell them your USB ports are dead and they will either put in a NEW mother board or swap out your computer.
If you are thinking about putting an e-cig passthru on a LAPTOP you paid good money for please think again (your choice of course). The cost to replace the USB surface mounted fuses on a laptop motherboard is EXPENSIVE. Some service centers will recommend just replacing the motherboard. A self-powered USB hub is my recommendation for laptop users. The current draw from an e-cig (or damaged cord) could kill a laptop USB port. Some external USB drives require 2 ports of power or an additional power source.
A USB e-cig charger draws less current and should not be a problem unless it goes bad.
PLEASE rethink USB passthru use on a laptop.
thanks for reading,
Rocket

Johnatl

Rocket, thank you for the info... I may get the internal card! I figured out the USB put out 5v so i am going to add some silicone diodes to drop the voltage to between the 3.6 and as close to 4 as i can. should take 3. is this still a risk? You obviously know your chit.. so teach me... :-)
and... are you saying this would apply to "store bought" USB pass thru's as well?
I have a home made battery pack for a 801 and a 901 in the works. id rather just get more 14500 batteries than a new Mother bd or pc at home..

Rocketman

a 1N4001 diode would drop you to 4.3 or so. (0.7 volt drop each). Check the web for USB 4 port ,Meritline.com has one I think. The USB spec will power a 901 or 84mm atomizer and the store bought passthrs work well. I just don't won't to fry a $900 motherboard just to look cool. Too big a risk using the USB on a laptop. A USB powered hub with a wall-wart power supply can also power USB devices, and doesn't even need to be used for data it you don't want. You can get them at Office Depot.
Check out 2 different homemade units in the DIY thread of this forum. One of them is mine. Used a pair on vacation.

Rocket

anonymous

Wondering how your project ended up?

Rocketman

Everybody needs one of these. Imagine being broken down on the road during the holidays, dead battery, flat tire, cell battery dead, and worst of all a DEAD E-CIG BATTERY.

Several models to chose from.
This one has 120 volt inverter, 12 volt jumper cables, air compressor, and

a USB port for your passthru.

Don't leave home without it.

and the second picture is a DC to 120 volt ac inverter. If you look close in addition to the AC outlet you will also see a USB port.

and one last idea for Christmas
a 47 inch Plasma TV with a USB Port. Perfect for vaping while watching the game (about 2 feet from the screen with a passthru).

Hoe Hoe Hoe

The Rocket
Happy Hollidays

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Hachiroku

Rocketman made some good points. Here is what I would do (I bought one from Vt Vapor)

Get an in-line battery box and the biggest AA size battery you can get. By 'biggest' I mean 2000 maH or so, whatever will fit in the battery box. Connect the USB connector to the PROTECTED!!!!! battery and then to the battery connector. Use the USB port to charge the battery, and then the battery powers the atomizer. A lot safer this way. I have one USB pass that has a battery and one does not. The one that doesn't draws so much current the monitor dims and shifts to the right when I hit it.

And as far as a laptop, I doubt you'll find anyone locally to replace the fuse sine they're surface mount, and Dell charges ~$200 or more for a motherboard and it'll probably cost another $65 to replace.

Hachiroku

Never mind that, I toasted ANOTHER atty today (a 901 this time), out on the road with no spares or ciggys!!! If this keeps up, I'm going back to cigs...

Funny thing was, I was using a USB passthru with a USB 'adapter' in the cig socket
http://www.alternativewireless.com/c...ne-charger.jpg

Glad I didn't use it to charge my cell phone!

Snarkyone

End your worries about battery failure, atomizer failure and constantly playing with your juice to refill your carts. Save juice and get a great hassle free mod. Juice Box Review on Vimeo

Rocketman

I can not believe this.
You are the Primo Atty Death Squad member.

What size (Protected of course) Li-ion batteries do you have on hand?
Do you have at least one 18650 or 18500?

and do you have an atty left? 901 or 510?

Rocket

Rocketman

That is one bee-ute-tee-full mod. just love the plate. much better than the black plastic Radio Shack look.

Hachiroku

None yet. I'm out of "play money" so I'm waiting to get paid. I'm actually looking at an AW 14650, a standard diameter 14mm battery, about 1100maH for my 'plastic toy' mod, and I want to get at least a 2200maH for the Atty Smasher (decided to change the name from Attilla, esp considering my woes with these ^&%$ things!)

I could rip apart a couple of old Laptop batteries hanging around, but my bet is that they are not individually protect, and I'm probably right...

I have another Clever Plan I'm hanging on to right now...!

Did you get to Home Depot today? 6 Trailer Parks for 9.95...
Or three Trailer Parks and three single AA lights. That's what I got!

Snarkyone

I am not blowing smoke up your butts either, the thing vapes like a beast! The juice I put in it Saturday is not even halfway done. The battery lasted me 2 1/2 days, before I changed it before it died, and at the current rate I won't have to change the bottle for another few days at least. It really helps you save on your juice expenses because there is no loss of excess juice, it drains right back into the bottle. One person thought he went through 3ml a day until he got his JuiceBox and found that it's actually closer to 1.5 ml once he wasn't losing all that excess juice.

Rocketman

I wonder if the draining back also helps keeps the atty clean. Sort of like a automobile fuel injection system continuously flows gas to the injectors (under pressure) and returns unused gas back to the tank. Juice goes up, juice comes back, juice goes up, - - -
??? Where does the dirty juice go that drains back???
and what is in the juice after it is heated, vaped, drains back, and cycled a few times, taste alright??
Do you continue to vape until the juice is all used up?

I ain't skeered. I don't even clean my attys. Just vape till they die.





Seller needs to get in touch with Rick, the Mod reviewer, e-cig photographer, and part time juice cop for some high-tech photos

Rocketman

Had someone email me about Protected batteries vs protected batteries, so I'll reply here.

Mod builders should always use protected batteries. Now I'll move on.

The Li-ion batteries in laptop supplies are unprotected cells. There is a circuit in the pack that protects against over charging, over dis-charging, over temperature, short circuits, etc. But each individual cell is "unprotected". When you see a 4400mah laptop battery pack it is arranged in two series strings of individual cells. The better packs will monitor not only each string, but cell balance between cells. This info is used to calculate "battery life".

Li-ion cells in e-cigs batteries like the 901, 401, 510, are "unprotected cells". There is a circuit in the e-cig battery that flashes at you and turns off the battery when the charge is too low, and cuts off the charge when it is too high. Most chargers also are smart enough to stop at full charge and not trickle charge Li-ion batteries. A no-no.

Protected cells have a little circuit board in the cell wrapper that protects from all the things discussed above. When the charge gets to "about" 4.2 volts it will stop charging, when it gets to "about" 2.7 volts it will stop dischaging. If it gets hot it will disconnect the cell. If if gets hotter, it will melt.

Protection circuits can fail. They usually fail (because of cheap underrated components used) in a safe manner. They open up preventing charging or discharging. But they will not protect against internal cell failure. If a cell goes thermal because of an internal failure the protection circuit will be of no help. Cheap poorly manufactured cells have the highest failure rates in the industry. The big laptop battery recall was not because cell protection failed, it was because of manufacturing deficiencies in the cells themselves. One of the hazards with Li-ion cells is when they fail, small pieces of battery material can be ejected from the battery case (blows entire vented end off)and each piece is like a small battery in itself. If it is hot and sparking, each little piece will be hot and sparking. A Ni-mh or Ni-cad battery will vent and spew goo, a Li-ion battery will spew fire. Batteries are designed with vents to help prevent from explosions. Nice but super hot batteries, spewing fire aren't nice either. Battery packs (multiple cells) are usually designed of thin plastic cases to prevent the pack acting like a bomb. I guess acting like a flame thrower is OK.

The e-cig battery, you know the ones with the unprotected cells, and pretty LEDs, will vent out the LED end. The little plastic lens will come off first.
Flashlight Mods will "probably " blow the switch" and vent out that end.
Unexpected warmth in any of them and it's time to put them outside on the sidewalk. Not in the trash.
Want to totally eliminate Li-ion battery risk? Give up the cell phone, laptop, and e-cigs. Go back to bungie jumping.

Thanks for reading,

The Rocket

Rocketman

A little food for thought on
"how many milliamphours (mah) of battery power do I need"?

If standard e-cig attys are about 3 to 3.5 ohms in resistance and we power them up with at least 3.7 volts then the atty will conduct between 1 and 1.2 AMPs of current. With a really fresh charge on a 3.7 volt battery that starts out at 4.2 volts but falls to 4.0 real quick then we get about 1.3 to 1.4 AMPs of current through the atty. The current will be sort of self limiting if we control the applied voltage (pick the battery voltage we want) and control the resistance (atty is what the atty is). The mah rating of the battery (honest rating) represents the total cumalative power that can be sucked out of the battery (at the lower cut off point, not zero charge).

If we have an atty that will draw 1.2 amps from the 3.7 volt battery rated at 1200 mah, then we have 1.2 amphours of power available (1.2 amps for a whole hour of vaping). 1.2 amps drawn from a battery rated at 300mah is 1/4 hour of vaping(15 min), and 1.2 amps from a 2400mah battery is 2 hours of vaping time available. Look at the various ratings for e-cig standard batteries, mega batteries and MOD batteries.

Now, at 6 volts the standard atty could draw 2 AMPs (as you increase the voltage applied to the atty, the current conducted through it goes up). Most 6 volt mods use two batteries in series to give the 6 volts, but you only get the mah rating for a single battery. Two 900mah 3 volt cells in series will give 6 volts, but at 900mah total power .
This gives about 30 minutes vaping time. You can increase the vaping time by reducing the voltage applied to the atty to 5 volts, (with a volt lost somewhere) and the current thru the atty will decrease.

Amps through the atty is what uses up the milliampHOURS of the battery. More amps, fewer hours.

The Highvoltage atty 4 to 4.5 ohms of resistance will conduct (use 4.5 ohms for the figuring) 1.33 amps at 6 volts instead of 1.75 amps for a 3.5 ohm atty on 6 volts. The higher current (amps) is one of the causes of atty death. Wattage dissapated by the atty as heat is what produces the heat that vaporizes our juice. Watts is what we want. More current burns up more watts. What? More current burns up more attys.

HV atty (4.5 ohms) runnning at 6.000000 volts conducting 1.33333 amps, produces 8 watts of heat.
Regular atty (3.5 ohms) running a 6 volts, produces 10 watts of heat, lots of vapor, right?
Regular atty (3.5 ohms) running at 4 volts, produces less than 4.6 watts of heat.

If you have a 3.5 ohm atty running on a weak 3.7 volt regular battery then you are only cooking your juice with 4 watts.
Dissapointing right.
Maybe not, 4 to 5 watts has gotten a lot of folks off tobacco. 5 to 6 watts makes most really happy with the vapor they get. 10 to 12 watts keeps your postal worker busy delivering attys to your door.

Decide what you want. Lots and lots of vapor, looooong battery life, fewer spare attys? There is no one solution.

The Rocket

Hachiroku

So, my Atty Smasher is now limited to 2.25A of current delivered to a ~2.7 ohm load. This means I'm running at 6.5 Watts. SO WHY AM I KEEPING THE ATTY MANUFACTURERS IN BUSINESS?!?!?!

I was running the Atty Smasher off the 12V rails of the computer's PSU, but (and I expressed before, it's been a LONG time since I did the conversion) only drawing .75 A. This should be about 3 watts. But since the supply is 8V higher than the output, the circuit is probably converting some of the voltage to current. I am now running off the 5V rail (the circuit can regulate inputs from 4.5V to 18V) so the output current should be lower.

Mind you, I am only measuring INPUT current. I'll have to devise a way to measure the output current to calculate the correct wattage for this mod.

This is interesting. At the lower voltage, the circuit is drawing 1.15A, but the atty stays cooler at the lower input voltage!

Rocketman

If the circuit is drawing 1.15 amps on the 5 volt rail then the input power is again volts times the current and would be 5.75 watts going from the power supply to the atty smasher, and 9 watts from the atty smasher to the atty.

and I agree, free power is interesting. without current measurements at the atty something seems amiss here.

Rocketman

My view on Li-ion batteries, safe use, and dangers.

Li-ion batteries have received a lot of bad press lately.
The laptop battery recall, overheating, fire and explosions, high voltage strings in hybrid cars, all tend to make us unsure if Li-ion batteries are really safe for us to carry around in our pockets.

I'll start by saying MOST problems with Li-ion batteries are when they are used in multicell battery packs. If a cell, single or one of a pack, gets below 2.5 volts because of deep discharge a quantity of the Li has been converted into lithium metal inside the cell. If the cell is then charged, especially at a high charge current, the electrical activity burns the metal lithium inside the cell case (yes, lithium metal will BURN). The reaction produces heat and pressure, which produces more heat and pressure, etc.

Single cell applications (like the e-cig battery):
Deep discharge causes most cells to go bad. Recharging them causes most fires. High current discharge can also generate excessive heat. What is high current? that really depends on cell capacity. High current to a little 901 battery is NOT high current to an 18650 cell. Protected Li-ion single cells will stop discharge before the cell gets below 2.5 volts, but will not prevent the cell from self-discharging over time to less than this. A suspected low cell should be charged slowly, at low current.
Most cheap chargers can't rapid charge a Li-ion cell. If you have a charger that can fast charge, less than an hour, then you have a "rapid charger".
The electronic control of an e-cig can short out causing excessive current, irrespective of switch operation. This could cause the cell to overheat possibly starting a fire, but the construction of most e-cig batteries would not hold enough pressure to "blow up". The somewhat underrated electronic controls and wiring in an e-cig are probably intentionally underrated. In the case of a shorted FET switch, the small wires will probably burn through stopping discharge. I personally had a 901 go thermal and had to put the battery outside on the sidewalk. Got hot, discharged, finished, no explosion. Was I just lucky?

Now, the multi-cell battery pack is a different animal altogether.
A 4400mah, 14 volt laptop pack contains about 1/4 the potential energy of a Grenade. An 8 or 9 cell laptop pack arranged in 2 or 3 series strings of unprotected cells must have extensive charge and discharge sensing to make them safe (safe?). If a string or cell gets too low the protection circuit will disable that string (forever). The pack will still work but at much reduced capacity with the disabled string. The concern is one cell getting discharged and the voltage in the remaining cells in the string will actually reverse charge the weak cell when it is used. That will cause the Lithium metal reaction that generates all the media hype. As you charge and discharge a laptop battery, the weaker, underperforming cells will be disabled.

So, are Li-ion batteries safe? Will they blow up? will they start a fire all by themselves?
If you don't abuse them, if the manufacturer used a reliable process and materials, if you don't mis-engineer the application, sure. How many have seen the youtube videos of Li-ion batteries blowing up? Do you keep a video camera trained on your laptop 24/7 waiting for an explosion? Or are these experiments?

Just don't store more than 100,000 joules of Li-ion battery energy in any single place. If you think a laptop battery is a bomb, what do you think a hybrid vehicle with lithiun batteries would be?

Late edit to this rant:

Charge and discharge rates are generally quantified in terms of charge capacity (1C, 2C, etc). Normal rechargeable batteries, NiCad, NiMh, Li-ion, LiPo, typically are rated at 1 C to 3 C charge/discharge rates. The 1C rate for a 900mah Li-ion 14500 cell is 900ma.
The 1C rate for a 2400mah 18650 is 2.4 amps. See the pattern? The capacity in mah is the 1C charge/discharge rate. Slow charge is less than 0.1C rate, fast charge is over 3C.

and a Rocket test question or two (didn't know there was a test?):
What is the discharge rate of a 300mah e-cig battery with a 3 ohm atty?

What is the discharge rate of a 2400mah e-cig battery with a 3 ohm atty?

The Rocket
MCaHNY

Hachiroku

Thanks, Rock! Clear as mud!

When the Prius came out, the fire departments had Field Reps from Toyota come around to tell them how to deal with a Prius accident. There is an accessible disconnect that needs to be disconnected in case of a charge sent to the car's body or other parts. And, when you're disconnecting the batteries in a Prius, there is a certain sequence that MUST be followed, or you end up with a Prius BBQ in your repair bay. You should see the stuff the Prius guys have, ie all the usual precautionary stuff the High Voltage linemen have!

Rocketman

Yeah, 280 volts running under the jewels.
and don't let anyone else see the answers:
The discharge rate of the 300mah battery with the 3 ohm atty, using the typical 3.7 volts, is 3.7 volts / 3 ohms / 300ma = 4.1 C. A fairly high discharge rate. Cookin.

The discharge rate of the 2400mah battery with the 3 ohm atty, using the typical 3.7 volts, is 3.7 volts / 3 ohms (about 1.23 amps) / 2400ma is only 0.5 C. Gee, hardly knows it's there

Find my "Size Matters" post for a visual reference

Rocketman

Here's a project for the home handyman/e-cig addict.
Whole house USB passthru wiring devices.

Never get caught without your e-cig again.

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Hachiroku

Even I don't need to be THAT wired!!!

Oggy

Rocket you have now taken OCD to an all new level, sooner or later they are going to make a Budwieser comercial about you. Vape on man