OKR-T/10, T/6, T/3 schematic circuit

[CraigHB]

I've mentioned this before, but if you want to know more precisely what a switch can handle in terms of amperage, you can measure its voltage drop with a known current.  Divide the drop by current to get resistance.  Alternately, you can use a milli-Ohm meter.  Use current squared times resistance with power set to a half Watt then solve for current.  Probably anything up to a half Watt is going to be okay, maybe up to a Watt if it's a big switch.  That's provided you're not exceeding the switches DC power rating in terms of Volts times Amps.

They just don't provide raw current limits in switch data sheets, only what the contacts can handle in terms of power.  It's always a guess for maximal currents at low voltages, but you can nail it down somewhat by measuring the switch's resistance. 

You can go by the current listed in the Volts/Amps spec (which is actually a power rating that includes maximal voltage), but finding a switch that isn't huge with 20A specified in its rating is going to be pretty tough.  Then it's overkill anyway.

[mamu]

Thanks for checking, breaktru, and thanks for the link to the switch manual.  I saved it for handy reference.

I think it's unfortunate that switch manufacturers don't provide charts for various DC voltages with corresponding amp ratings for their switches.  I've spent hours searching for a source like that, but nothing available, and you would think that switch manufacturer would test for that when designing a switch.  That would save a lot of wondering what amps we can push through the switch at a lower voltage.

I agree with Craig he's always spot on about these things -  "There's a point where the switch hits a current limit regardless of applied voltage.  Unfortunately, absolute maximum currents are not provided for DC switches.  It's pretty much a guess." and "The main thing to take away is that within reason, you can use a higher current with a lower voltage without significant loss in switch longevity."

And I think we talked about this before in that if we're not sure about amp load we can breadboard and test the switch's contacts for heat and resistance at higher amp loads and that would at least let us know if the switch is handling higher amps.

I also read your edited comment and lol yeah you're absolutely right there. 

[mamu]

I've mentioned this before, but if you want to know more precisely what a switch can handle in terms of amperage, you can measure its voltage drop with a known current.  Divide the drop by current to get resistance.  Alternately, you can use a milli-Ohm meter.  Use current squared times resistance with power set to a half Watt then solve for current.  Probably anything up to a half Watt is going to be okay, maybe up to a Watt if it's a big switch.  That's provided you're not exceeding the switches DC power rating in terms of Volts times Amps.

Thanks Craig.  I hadn't seen this before. 

[Breaktru]

NKK has a break down for re-rating of their AC switches to DC. The formula depends on the type of load. Resistive, Inductance, Lamp, Motor or Capacitance. See: ReRating Current For 125V AC Switches

[Visus]

From my own experience in being a dc electrician 26 years and observing the contacts on a 50mA switch handling upwards of 12A.  I would say its pretty much a situation of "CTA" cover thy arse.  I pulled apart my aa battery box 50mA on/off switch, there literally is no pitting or carbon deposits with daily use after ~8 months.

My power button is a 3amp c&k and it also has not had any issues so from experience with quality switches in our use those theorems from Breaks experience that he  has recommended of switch ratings are awesome.  We are not switching a motor or constant load to cause more concern IMO.

But seriously a 50mA switch with a 0v drop on a booster and .02-3v sag on a buck is very impressive.

If it is good enough for an airplane to use lower rated switches at double the quoted rating on their panels with a continuous load,  were barely scratching the surface..

Good read:
http://www.bandc.biz/pdfs/Switch_Ratings.pdf
 

I can also tell you that switching an
8-amp landing light with a 4-amp "lamp" rated switch is not
an automatic formula for welding. The 200% "overload" will
indeed reduce the life of the switch. However, let us suppose
the switch was originally rated for 10,000 cycles (a low
estimate) and the reduction was to 10% of rated life(also
very low)

Just because the numbers stamped on
the side of the switch don't mention a DC capability doesn't
mean that the switch doesn't have one. Manufacturers are
unable to put ALL of the information from the chart onto the
side of every product, the lettering would be too small to
read!
The article also alluded to a 3X increase in the price of
switches to get "DC rated" devices

Its amazing how a cheap or inexpensive switch rears its head very quickly like the madvapes old 5A  horn switches,  you look at the reviews and some last a week, month or two, and fail.   I asked on here would the battery box on/off be ok to use and Break said he had used it but changed it out just to safe so I used it and like I said no issues with 4 aa boxes in constant use..  Believe you me if a switch is having issues it will show carbon and pitting on DC applications str8 off, our railroad switch points need cleaning every  year on schedules because of that issue..  But were talking a choo choo train @16k, 32k, 48k amps depending on how many 8 car trains are in the same system and believe you me none of those switch points are rated for  even 32k amps...   If the bypass is not closed when opening a switch, after you arc it,  it literally looks like the moon with pits everywhere.   20 years ago we installed a mosfet switching system for Ohare airport track yard  it  was problematic and everyday it needed replaciing fuse or replacement of fets, so even with fets there can be issues of manufacturing not being up to specs..  It was removed and back to old copper buss switching..  Then tried again --partial success-

So that 50mA switch is a wowzer..  Good solder joins and short runs I think with many quality brand switches we are fine..  Now watch my mods all go belly up soon 

[CraigHB]

Almost exclusively switch failure is due to contact failure, not overheating which would be the effect of too much current.  I don't think I've ever seen a switch fail that way.  I've seen the contacts wear out and fail to conduct properly lots of times, but I've never seen one die from current overload other than a short circuit.

Most of the time, the raw current a switch can handle is fairly large with respect to it's power rating.  For example, a good quality switch might have 2 mOhms resistance.  Allowing it to dissipate a Watt provides over 20A of current flow.  That kind of resistance would be typical for a switch that has a rating like 28V/5A.  That's not to say for sure a 28V/5A switch can handle 20A, you'd have to measure it's resistance to know for sure.

There's a huge difference when switching motors and transformers as Visus mentioned.  When they conduct, they don't like to stop conducting.  When switched off they create something called back EMF.  It creates impressively large voltage spikes across switch contacts which play hell on them.  Typically a flyback diode has to employed to allow the energy to dissipate through the diode instead of the switch.  Without one a big motor can destroy a switch in just a few cycles.  Atomizers are much easier on switches as they are purely resistive and don't exhibit those inductive effects.

[Breaktru]

Craig: I have a question.
When using a pushbutton switch for Vin on a DC/DC converter like the OKR, do you know what the load type for the switch is in play? Resistive, Inductive or Capacitance?

[CraigHB]

There's a term called reactance which is a blanket term for the effects of both capacitance and inductance.  Reactance is the quantified reaction to changes in current, hence the term reactance.  It's what makes those big voltage spikes when current suddenly changes. 

Reactance is graphed with inductance on one side of an axis and capacitance on the other.  Capacitance and inductance are like opposites.  Reactance increases with frequency for inductors and decreases with frequency for capacitors.  In a circuit, reactance can cancel between a capacitor and inductor.  The frequency at which this happens is called the natural frequency or resonant frequency.

The vector sum of reactance and resistance is impedance.  It's a vector quantity meaning it's graphed on a plane with an angle and magnitude.  The "x" axis being resistance and the "y" axis being reactance.  The ratio of reactance to resistance is significant.  That's indicated by the angle of the impedance vector with respect to the x axis. 

Various devices have various amounts of reactance.  Even a straight wire has reactance, albeit very small, it's vastly resistance there.  Motors and transformers have a lot of reactance compared to resistance.  Large devices can have significantly more reactance that resistance.   They can have large angles in their impedance vectors.

For a converter there's not a huge amount of reactance relative to the resistance.  There is some considerable reactance there, capacitance due to the input and output capacitors and inductance due to the inductor used to do the input and output conversion.  However, resistance is more significant.  The input reaction to sudden changes in current is not substantial though it's a major consideration for the internal controls.  At the least, it's not enough to be concerned about wear on switches.

[Breaktru]

Thanks Craig. As always, I truly appreciate your professional explanation.

[CraigHB]

Welcome.

Geez, I could go on for hours on this topic.  What you're doing is cracking open the door of AC theory which is what electronics is greatly more about than the DC stuff.  Though AC theory can really give you a headache, it's pretty complicated.  I have to go back and review stuff all the time when I'm doing AC stuff.  That's not to be confused with the AC coming out of your wall.  AC theory covers just about everything including radio, controls, and even some aspects of digital design.

I actually skirted your question with a long answer.  There's a reactive load due to a DC-DC converter, but I don't know whether it's capacitive or inductive.  You actually have to calculate the step response then observe the phase angle to tell.  So, the better answer to your specific question is I don't know.  I check step response all the time with designing my own coverters, but I've never looked at the phase angle, pretty sure it's inductive though.

[ternadorex]

Ok first I want to thank you all for the wealth of knowledge that you put out here. Without this I don't know that I could have built my okr mod, it would have taken much much longer to figure it out. I am a plumber by trade and water and electricity don't mix. I used mamu's diagram minus the reverse polarity protection as I am using 7.4 lipo packs. Only one way to plug them in so no big threat there. I installed everything in a temporary box for batt life testing and all before I finish my box.

[Dasen22]

Ok first I want to thank you all for the wealth of knowledge that you put out here. Without this I don't know that I could have built my okr mod, it would have taken much much longer to figure it out. I am a plumber by trade and water and electricity don't mix. I used mamu's diagram minus the reverse polarity protection as I am using 7.4 lipo packs. Only one way to plug them in so no big threat there. I installed everything in a temporary box for batt life testing and all before I finish my box.

Nice to hear that you got it made 

[Stevo2569]

Hey Everyone. Been reading these boards for a couple months now and absorbing as much as I can. Finally got the rest of my parts from china for my OKR T/6 mod. Everything is bread boarded and working well. But now I've decided to use a digital pot instead. Posted in another thread with the same question. Hope that's OK? Can someone tell me whether this Digital Pot will work?
http://www.mouser.com/Search/ProductDetail.aspx?R=X9313ZSZT1virtualkey57760000virtualkey968-X9313ZSZT1
And what size resistors to parallel? Don't want to start drilling holes before I get everything cause the case is a little tight. Trying to get these last couple parts ordered before I put everything on a PCB and cram it in my case.  THANKS.

[Stevo2569]

Well found a supplier for the DS-1869-10 but they're off for a week and a half for National day so screw it guess ill do the analog pot for now and incorporate the Digital on the next one. In case someone is interested here's the link.
http://www.ebay.com/itm/DALLAS-DS1869-010-SOP8-Digital-Potentiometer-/360848136035?pt=LH_DefaultDomain_0&hash=item5404399763
Maybe I will be received better if I start a build thread? Just wondering why I didn't get any reply's?

[Breaktru]

The OKR requires a 200 ohm pot. Using a value higher than that w/ a parallel resistor will wreck havoc on linearity. Adjustment is a nightmare.
See: http://breaktru.com/smf/index.php/topic,244.50.html

and: http://breaktru.com/smf/index.php/topic,1015.msg16441.html#msg16441

[MP5k]

Hi everyone first time poster here. I have a couple of the 3 wire led volt meters how would I wire them to show how many volts I am using. thanks in advance and thank you to everyone one here for all the great info.

[Stevo2569]

The OKR requires a 200 ohm pot. Using a value higher than that w/ a parallel resistor will wreck havoc on linearity. Adjustment is a nightmare.
See: http://breaktru.com/smf/index.php/topic,244.50.html

and: http://breaktru.com/smf/index.php/topic,1015.msg16441.html#msg16441

Yeh saw those, but thought you used it anyway?
Thank you for the reply.

[Rigure]

Hi everyone first time poster here. I have a couple of the 3 wire led volt meters how would I wire them to show how many volts I am using. thanks in advance and thank you to everyone one here for all the great info.

Just connect the black wire to common ground and the other two to the positive of what your measuring. The red wire is for powering the led metter and the white wire is for measuring the volts. You could even just connect the white wire to what your measuring and the other two to power and ground. Either would work.

[MP5k]

I thought so but I put way too much thought in it like is could not be that simple.lol
Thanks for the help.

[steamEngine]

Yeh saw those, but thought you used it anyway?
Thank you for the reply.

He did use it in his side x side mod

[Stevo2569]

Alright guys. I might of burned my chip cuz when it was on the bread board it was working great and now that its on the PCB I'm getting no output from it. Might have shorted through some solder splatter I noticed after the fact. Never saw smoke or anything. Rechecked all connections and schematic. Tested V at all connections and they all stop at the OKR. Pot good, Resistors good, Diode good, Fuses and PTC's good,  Vin good, Vout no good. Should there be impedance across Pin 2 to Pin 4? I have none. Is there a better way to test chip? Thanks in advance.
Stevo

[Stevo2569]

Oh. If it is toast, thought I would get the Raptor 10 to replace it since its got the same Pins layout, The T/10 is backordered and I could just unsolder and resolder. Thoughts?

[CraigHB]

You should be able to do that without issue, remove and replace the regulator.  You've probably checked everything you can in terms of peripheral circuitry.  You could pull it out and check in the breadboard again.  Usually parts are pretty tough but there's certain things that will fry them, reverse polarity is one and shorting out traces on the PCB would be another.

[Stevo2569]

Yeah. Ill pull it and Breadboard it, check it but I think its fried. Thanks for conf on the raptor 10 Craig. Didn't c it when I ordered the T/6, cuz T/10 got gobbled up already. Nice to know.  If anyone knows of a way to confirm a burnt OKR, let me know. Thanks
Oh meant to say P-FET good Too.
Stevo

[Breaktru]

One other thing Stevo. When you remove the chip, put a voltmeter across pin 4 and pin 3 and just hit pin 2 and pin 3 with the battery voltage. Don't wire up Pin 1 or use any other parts but batteries and voltmeter. You should see 0.591 V. If that checks okay, add pot and resistor and check for variable output.

[Stevo2569]

Thanks Break, I put it on the BB and its doing the same thing as it was on the PCB. I get like .01V or 5 mV on 200m scale out of Pin 4 with or without Resistor or Resistor/Pot combo. Id say its prob toast right? Thanks
Stevo

[Breaktru]

Thanks Break, I put it on the BB and its doing the same thing as it was on the PCB. I get like .01V or 5 mV on 200m scale out of Pin 4 with or without Resistor or Resistor/Pot combo. Id say its prob toast right? Thanks
Stevo

Yep, sounds like it.

[Stevo2569]

Oh well. Next time I'll be more patient instead of rushing to fire it. But good excuse to upgrade to 60W.  . Probably wrong thread hope y'all don't mind me asking but as far as I can tell from the data sheets the raptor and OKR are pretty much the same as far as components go right? Like caps, pot and such. Thanks a lot guys.
Stevo

[Rigure]

Finished up another for my wife...finally got her off that ego batt mod I did for her. Put a Mutation X on top with a .65 ohm coil. She loves it. Thank you again for the ground breakers that did it first allowing me to fillow. One question tho, can I use a three 18650 setup to power the chip?

[Breaktru]

Very nice and nice and need. Congrats.
I was thinking what the pink and white decoration was on the cover, until I blew up the photo and discovered it was a reflection of your hands holding a phone camera. Ha, Ha

[david4500]

can I use a three 18650 setup to power the chip?

Spec sheet has max input voltage listed at 14v. 3x18650s @ 4.2v would be 12.6v.

[Rigure]

Is there any difference in resisters with the 12.6 imput?

[Dropsomegears]

Yes, but omit the zener and the P-FET as they are not needed and replace the batts with the DC connector.

Hello everyone. Havent been on in a while and now I got the bug again. I plan to make a okr t6 pass through and it was suggested (outside of breaktru) to use a 1500 uf cap. So Mamu you're saying I don't need that. I was looking for a diagram to follow and was pointed to this diagram (again outside of Breaktru). My search skills  Yes its a different chip I was going to wire accordingly. My power source is a repurposed power supply (Junked the equipment) OUTPUT is 12V  =  3.33A  I'm hoping the answer is no because I cant find a 1500UF cap locally. I can find 1000uf and 2000uf but thats it and they are friggin huge. I'm planning to put in a 2x2x1.5 enclosure. Any help will be greatly appreciated. 

[Breaktru]

The 1500uF that is shown in your diagram is an output capacitor for the D12S05020. It has nothing to do with passthru or the OKR-T/6.
If you would like to add a capacitor for your OKR-T/6, a 22uF 10v or 16v can be added to the input and not the output like your schematic shows.
Personally, I don't use caps on my OKR.

[Dropsomegears]

The 1500uF that is shown in your diagram is an output capacitor for the D12S05020. It has nothing to do with passthru or the OKR-T/6.
If you would like to add a capacitor for your OKR-T/6, a 22uF 10v or 16v can be added to the input and not the output like your schematic shows.
Personally, I don't use caps on my OKR.

Sweet!! I can start building tomorrow. Provided the power supply works. Lol.

[Louis4052]

Hello all. I'm new to modding and have been reading through this tread for a few weeks.  I got my first okr mod up and running after tearing it down a couple times. It's only firing a 6 volts with the trim pot all the way up. I checked everything over and over and finally looked at the specks for the pot. 200k! Damn. If I turn it down even a smidge voltage out drops to .59 ish. I have a 200 ohm pot comming.   Hopefully the right pot will get this working right.

[Breaktru]

Hello all. I'm new to modding and have been reading through this tread for a few weeks.  I got my first okr mod up and running after tearing it down a couple times. It's only firing a 6 volts with the trim pot all the way up. I checked everything over and over and finally looked at the specks for the pot. 200k! Damn. If I turn it down even a smidge voltage out drops to .59 ish. I have a 200 ohm pot comming.   Hopefully the right pot will get this working right.

Yup, you need a 200 ohm pot. Turning it up to 6V is zeroing out the pot with only the fixed resistor in play.
Dialing down the pot puts to much resistance in the circuit with the 200K pot.

And... welcome to posting. Don't be shy, we welcome your posts.

[Louis4052]

Yup, you need a 200 ohm pot. Turning it up to 6V is zeroing out the pot with only the fixed resistor in play.
Dialing down the pot puts to much resistance in the circuit with the 200K pot.

And... welcome to posting. Don't be shy, we welcome your posts.

Awesome! It'll be hot vapes till Monday then.
I'll post a pick when I'm back at the destktop.

[Visus]

 

Awesome! It'll be hot vapes till Monday then.
I'll post a pick when I'm back at the destktop.

You could put a 200 ohm resistor in parallel for 198ohms

it wont swing as nice but it will give ya the whole range til delivery

[Visus]

I rewired my Okr mod grabbing ground at the atomizer and it made a huge difference in performance.  HUGe difference, than direct off the battery.  I guess/now know it, without seperate  sense connections, wiring this way it regulates and senses the load better.   I now have a 0v drop at the atomizer where b4 it was ~03v.  Same with the evercool mod rewired ground at the atomizer and 0v drop. 

I thought I would share this info...
I noticed it as soon as I vaped and had to meter it and was pleasantly surprised.  The mod I built I had to grab ground at the atty due to space and I rewired my evercool to the same result.

It's now hitting spec sheet tolerance .01.  It makes sense after thinking about it.

[Stevo2569]

Wanted to thank all of you guys for putting all this info out there. Finally got mine done. Took a while to find a switch with a short enough body to fit. Not my first choice but other than ordering 500 of the SS version I settled on this blue button to stay with the theme of blue Leds for the 3-dig and reverse polarity indicator.

[Breaktru]

Congrats Stevo 

[Stevo2569]

Thanks Break. Only problem I found is 3-dig blue that I got off amazon that shipped from China. Freakin month shipping was bad enough turns out the dang thing reads 0.6 V off fully charged and 1.8 V off almost dead. Luckily didn't permanently glue anything in in case of problems. Trying to find a blue replacement but probably gonna have to get a red.   

[Breaktru]

That sucks Stevo. Did you wire in a slide sw for output and battery V readings?

[Dropsomegears]

Just wanted to show some Pics of boxes I wouldn't have been able to complete if it wasn't for this wonderful site.

Recent T6 pass thru








T10

[Breaktru]

Just wanted to show some Pics of boxes I wouldn't have been able to complete if it wasn't for this wonderful site.

Cool. Congrats on your builds

[Stevo2569]

Yeh 3-Pos switch wire to Vin and Vout. V out seems good. Vin Full charge 8.2V on VM = 7.6V on 3-Dig. Vin low charge 5.8V on VM = 4V on 3-Dig. Vout 3.41V on VM = 3.53V on 3-Dig. Vout 5.62 on Vm = 5.75 on 3-Dig.

[Breaktru]

Could be a defective meter but seeing that there is only a 0.12v difference on output between your VM and the DM and a 0.6v to 1.8v difference on input tells me that perhaps the 3-pos switch may be the culprit of high resistance. Also check you soldering on the input voltage side of the switch.

With the switch in the input voltage reading side, take a jumper and jump out the contact points and see it the voltage drop changes.

[Stevo2569]

Sounds like a plan. I'll test it out later. If its the switch I'll replace. If its a solder I'll leave it and compensate cuz I would want to compromise any other solder joints. Thnx Break

[Stevo2569]

It was the switch. Everything works fine now.  Thnx.
Been tryin to find a LIpo for my other chip and case. Ill make the next one a lot cleaner.