Actually... resistors and linear regulators are almost identical with regards to rejecting the power as heat. The exact same heat generation and power loss equations are used on both. Switchers are the exception.
Resistor vs Regulator
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Actually... resistors and linear regulators are almost identical with regards to rejecting the power as heat. The exact same heat generation and power loss equations are used on both. Switchers are the exception.
I was only speaking of what I have tested first hand. For what we are doing resistors seem to produce more heat and by which more power wasted than linear resistors. You may be right but the experiments that I have done lead me back to my original conclusion that resistors are not the best choice for 5v e-cig modd's.
And to get back to the OP.. yeah, Vregs are a much better solution than simple dropping resistors. And switcher regs are much better than the linears.[/quote]
I think you have already agreed with me in the past,
I think you have already agreed with me in the past,
Too bad these aren't just a bit cheaper (who knows, in qty if you are building a mod to sell commercially, you might be able to negotiate a much better per unit price): 3A Adjustable step down switching voltage regulator
Or maybe a boost regulator like this: Pololu - Pololu Adjustable Boost Regulator 2.5-9.5V
Both are kind of pricey, but seem to be a decent fit for the application...
Or maybe a boost regulator like this: Pololu - Pololu Adjustable Boost Regulator 2.5-9.5V
Both are kind of pricey, but seem to be a decent fit for the application...
Never mind on the boost regulator... still won't supply enough current for the application.
If you're just messing around, BEC's like the one listed below will probably work nicely. They are jumper selectable for 5V or 6V output. (And you can find them for less if you're proficient w/ eBay):
RC UBEC BEC device Switch Mode 5v 6v 3A Max 5A NEW - eBay (item 270501503220 end time Dec-21-09 11:38:26 PST)
RC UBEC BEC device Switch Mode 5v 6v 3A Max 5A NEW - eBay (item 270501503220 end time Dec-21-09 11:38:26 PST)
I was thinking about using a BEC, but I can't find one that fits nicely in a box mod. I've got some other ideas, but the width on these is just a hair too big (1-2mm).
Well.. started to put together a USB passthrough and was going to use the shell of a "dud" 510 battery, started to rip it apart to get the led and batteries out leaving just a button and the connector head and it started heating up and making that wonderful bleachy electronic burn smell that preceeds something popping in your hand so ill go find it in the snowbank hopefully discharged tomorrow 
Anyhow, found this thread with you guys talking about $6 regulators... are you crazy??
LM317T is a variable regulator, can put out any voltage 1.2V+ using two different resistors to set your output, for 21 cents. **21 CENTS** and thats individual price online not wholesale bulk price. they're even $2.29 at radioshack. But they sell $2 chinese phone adapters for $35 so thats normal.
You can get 4.17 volts using a 240ohm and 560ohm resistor, right in range of a fully charged 510 battery, or 150ohm and 330ohm resistors gets you 4 volts (id rather undershoot by .2 volts than overshoot by .13 on feeding my atomizer *shrug*)
I doubt a 1V stepdown will generate much heat as well
Anyhow, found this thread with you guys talking about $6 regulators... are you crazy??
LM317T is a variable regulator, can put out any voltage 1.2V+ using two different resistors to set your output, for 21 cents. **21 CENTS** and thats individual price online not wholesale bulk price. they're even $2.29 at radioshack. But they sell $2 chinese phone adapters for $35 so thats normal.
You can get 4.17 volts using a 240ohm and 560ohm resistor, right in range of a fully charged 510 battery, or 150ohm and 330ohm resistors gets you 4 volts (id rather undershoot by .2 volts than overshoot by .13 on feeding my atomizer *shrug*)
I doubt a 1V stepdown will generate much heat as well
Yeah..checked the datasheet and it reads 3 amp and <0.5v dropout. The control pin is a nice bonus. At that price its a much better deal than the TI.
Find me a good booster at a lower price than the TI and I'm your biatch for life
I've tried the TI booster with a 18650 battery and it was very disappointing. Doesn't seem to me that protected lithium ions can supply the current needed for what we do. My experience with protected batteries is that they are not ideal for high voltage e-cigs. The cut off amperage is to low for what we need.
I use unprotected and add my own protection pcb that allows a 10 amp draw.
DealExtreme: $1.27 Charge/Discharge Protective Circuit Board for Rechargeable Li-Ion Batteries (17.4mm*1.9mm)
Protected do work fine if you make sure to include the capacitors.
AW has some protected 18650 that output over 5 amp but they are pricey.
AW 18650 Protected 2600 mAh Rechargeable Lithium Battery - New Version
I push the boost chip to just shy of it's 12 watt max continuously and I've never had any of the above solutions fail to put out rock solid voltage. Don't give up, the booster makes for a kickass vape.
I tried it on the ultrafire 3000mah protected batteries only. Maybe different batteries would produce a different result. The 18650's are expensive and I do not have an unlimited amount of money to buy and compare different manufacturers batteries.
Those bats have a very low discharge. I believe its 0.5C so they definitely won't cut it. The guaranteed way to get it to work reliably is grab some unprotected with that pcb I linked from DX. I've done about 15 mods that way and they work like a charm
I have run into the same amperage problem trying to lower voltage from 2 protected 3.7v cr123's to 5v with a regulator. Using unprotected cr2's @ 3v's eliminated this problem. This is the only reason that I am not a huge fan of protected batteries.
Those bats have a very low discharge. I believe its 0.5C so they definitely won't cut it. The guaranteed way to get it to work reliably is grab some unprotected with that pcb I linked from DX. I've done about 15 mods that way and they work like a charm
Thanks for the info. I guess the only way to fly is unprotected and supply your own protection if you feel you need it. Which leads me back to my original conclusion that protected batteries as they are for what we need are xxxx.
Yeah..that can happen. A 510 at 5v demands about 2.2 amps which can easily trigger the protection. The problem with the cr2 unprotected in series is that you are stressing the hell out of the bats drawing that much current. They can and have failed. Tons of opinions out there but I would recommend against it. The reward just isn't worth the risk when you can solve the issue so easily using 1 proper sized battery and with protection. The added advantage of using 1 cell is that you can then add USB charging for just a few bucks to the mod.
It would seem to me that using one unprotected 18650 battery at 2.2 amps with a protection circuit that can handle 10 amps would be no less dangerous than 2 cr2's at 2.2 amp's. If I were to provide my 2 cr2's with protection to 10 amps doesn't mean they won't fail and vent at 3 or 4 amps. I am not an expert so if I am wrong please explain.
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Using an 18650 means the bat is large enough to supply the current requested without stressing the bat. Over and under discharge is never an issue with mods since the chargers are invariably protected anyway and you get no vape long before over-discharge is an issue. The 10 amp cut off is there to handle the remaining danger of a short (the over and under discharge protection is just a bonus).
Edit: I should mention that I think CR2's are absolutely the wrong choice for high voltage vaping. Even if they were protected (which I've never seen), they are just unequal to the task. It's a pretty contentious issue so I expect lots of "Ive vaped them for 4 months without a problem" posts
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Another advantage of active voltage regulation over passive (resistor) regulation:
With or without a resistor, the voltage starts high, and as the battery discharges goes lower and lower.
Simply stated, this often leads to an atomizer cycle of too hot->sweet spot->too cold when vaping.
By using active voltage regulation, the user can dial in the sweet spot voltage which remains more or less constant throughout the battery/vape cycle.
With or without a resistor, the voltage starts high, and as the battery discharges goes lower and lower.
Simply stated, this often leads to an atomizer cycle of too hot->sweet spot->too cold when vaping.
By using active voltage regulation, the user can dial in the sweet spot voltage which remains more or less constant throughout the battery/vape cycle.
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