EverCool Variable Voltage Mod

[rchriste]

The sad part is I know it is something silly.

Been there... done that.... Will be there again.... will do that again.

One more question for you when you get home.. Are you using the led or did you skip that part? It proly doesn't matter but the more we know, the better our chances of finding the problem. Maybe I should rephrase this question. Have you done anything differently than bigblues original plan from page 1 and if so, what? If not, disregard.

 

[rchriste]

View attachment 33581

Off the top of my head... I'd say yes, you got it right. Does the other side of the trimmer pot have a diagram? Doesn't matter right now.. your readings when you get home will hopefully tell all. Measured resistance of your fixed resistor and measured resistance from pin 5 to ground (with rotation of the pot)

I'll try to check in this evening. If not there are plenty of minds at work here I'm sure.

 

[Ruppy]

A silly question Ruppy, did you use the center tap of the pot and one outer tap or did you use the two outer taps? That's what it sounds like, you used the pot as a fixed resistor.

Been there... done that.... Will be there again.... will do that again.

One more question for you when you get home.. Are you using the led or did you skip that part? It proly doesn't matter but the more we know, the better our chances of finding the problem. Maybe I should rephrase this question. Have you done anything differently than bigblues original plan from page 1 and if so, what? If not, disregard.

Originally I had a LED but I removed it from the circuit for troubleshooting purposes. Ill add it back once everything else is up to par.

It is exactly as in this pretty diagram from Bigblue other than the LED and using electrolytic caps

 

[rchriste]

It is exactly as in this pretty diagram from Bigblue other than the LED and using electrolytic caps

It helps to know that. To be specific to the example schematic then... First measure the resistance between E4 and E5. Should read about 220 ohms.

Second measure the resistance between A3 and A5 while turning the pot in both directions. Should read from 220 ohms at one end of rotation to 420 ohms at the other end of rotation. Assuming a 200 ohm pot.

If either or both of those are wrong then I'd focus on that part of the circuit. If they're both right then we're back to the drawing board.

I have to head to the garage to do some welding now. TTYL.

 

[Ruppy]

Yup resistance is right on from ground to E5. 199 ohms - 426 ohms from A3-A5. E4-E5 is 218 ohms. This tells me either A something in 2 or 4 is not connecting properly or B the chip is bad...... Working on some pics now

All that said I resoldered everything agin and I now ger 5.27 volts no matter where the pot is set......... Im ready to scream. I have no idea how i can vary the ohms via the meter across the pins but it has no affect on he voltage.....

Heres some pics. No laughing at my soldering skills and bear in mind I have not polished my tube yet.View attachment 33592View attachment 33595

 

[rchriste]

Yup resistance is right on from ground to E5. 199 ohms - 426 ohms from A3-A5. E4-E5 is 218 ohms.

I'm scratching my head over this...... (IF) your fixed resistor reads 218 ohms (THEN) how is the total able to drop below that value to 199? (It's a rhetorical question)

I'd try this next. Pull the caps. According to bigblue it can be done and he's run one of these without the caps but he also pointed out that TI didn't recommend it. For the sake of testing, I'd see if that removed the problem (fixed voltage) There may be some leakage there causing this difference in resistance that I'm not understanding. If it does then new caps would be in order.

I'm sure you've probably gone over your board with a fine toothed comb checking for lateral shorts across solder joints. Right?

Other than those two things... I'm out of ideas.

 

[rchriste]

Ruppy, forgot to say, that's going to be nice when you get it done. 1 hole for the switch, 1 for the pot and 1 for the led. Is that correct?

Two questions

1 how long is it going to be when it's done?
2 how do you get that really short cap with the atty connector to stay attached? Will it get soldered to the pipe under it?

 

[Ruppy]

I'm scratching my head over this...... (IF) your fixed resistor reads 218 ohms (THEN) how is the total able to drop below that value to 199? (It's a rhetorical question)

I'd try this next. Pull the caps. According to bigblue it can be done and he's run one of these without the caps but he also pointed out that TI didn't recommend it. For the sake of testing, I'd see if that removed the problem (fixed voltage) There may be some leakage there causing this difference in resistance that I'm not understanding. If it does then new caps would be in order.

I'm sure you've probably gone over your board with a fine toothed comb checking for lateral shorts across solder joints. Right?

Other than those two things... I'm out of ideas.

Yes ive checked each hole to make sure its not touching any other joints that it shouldnt be. something HAS to be bleeding or shorting to get the values I have but I cant seem to find it.

Starting to think I should just start over with another chip and rebuild from the beginning.

Im going to try the cap idea first though. Im sure rebuilding will solve it but I REALLY want to know why its not working at this point as a matter of principle.......

 

[rchriste]

Im going to try the cap idea first though. Im sure rebuilding will solve it but I REALLY want to know why its not working at this point as a matter of principle.......

I'm right there with ya. Don't like unsolved mysteries. Xing my fingers on the caps.

 

[Ruppy]

Ruppy, forgot to say, that's going to be nice when you get it done. 1 hole for the switch, 1 for the pot and 1 for the led. Is that correct?

Two questions

1 how long is it going to be when it's done?
2 how do you get that really short cap with the atty connector to stay attached? Will it get soldered to the pipe under it?

Yes the lowest hole is for the pot. The middle is the fire LED. The top one is for the C&K switch.

1 Its currently 5.5 inches from tip of the atty connector to the bottom. I am going to trim the bottom battery cup short like the top cap so it will be about a quarter inch shorter when completely done. It will house two 16340s. A 18650 will fit with the same design if I wanted to make one with a 4050 booster.

2The cap has a piece soldered inside so it slides down inside the piece below it. It will not need to be soldered on. Ill ever so slightly bend it so it slides tight.

 

[rchriste]

My mistake, sorry.

 

[breaktru]

Do you have a link to that 4050 booster? I'm interested!

It's ingenious. Can't wait to see it all shinny'd up.

There is a circuit schematic for the booster in my signature

 

[rchriste]

My mistake. Sorry.

 

[Ruppy]

Thank you breaktru. You just keep saving my life.

Can that digital pot be replaced by a 100 ohm linear pot (wildguessing)? If I use it with a DVM built in to the mod I think the DPOT would be fantastic. Without a DVM built in, I need a rotary so I have an idea where it's set to. I might try it both ways. Hey.. I'm retired and need to find things to keep me out of trouble.

Does this thing run warmer than the ptr08100 I guess I should say; Is it as efficient?

I like that it can run off of a single bat instead of two. I'm thinking an 18650 would be my preference with this circuit.

Does that 100K fixed keep the voltage from going too high? Does the data sheet define that diode with a 1Nxxx. Too many questions. I'm going to go get the data sheet so you won't have to answer all of these questions.

Thanks again.

I built a box mod with Breaktrus 4050 schematic and it works very well. It is definitely not as efficient. By my calculations its about a 20% loss in runtime since your boosting 3.7 to the output voltage. With an 18650 I dont feel it real bad. I really like the 4050 chip and find it super easy to work with.

It's ingenious. Can't wait to see it all shinny'd up.

You and me both Ive thought about polishing it a few times but I keep reminding myself to wait till its completely done


In regard to Breaktru saving your life,
Breaktru, Asdaq, Attypops, WillyB, Bigblue and countless others over here have helped me more than they will EVER know. I do my very best to research and read all I can. I havent posted alot in the modders forum because there is such a wealth of info. THANK YOU to all the modders who so willingly share their ideas.

 

[rchriste]

My mistake. Sorry.

 

[breaktru]

I'll PM you. Don't want to interfere with the evercool thread any more than I did already, sorry guys.

 

[breaktru]

Ruppy, the datasheet claims up to 90% efficient.

 

[rchriste]

I built a box mod with Breaktrus 4050 schematic and it works very well. It is definitely not as efficient. By my calculations its about a 20% loss in runtime since your boosting 3.7 to the output voltage. With an 18650 I dont feel it real bad. I really like the 4050 chip and find it super easy to work with.

That sounds probable. The circuit used for the data sheet got better results but once a more expanded circuit is applied the results usually change and depending on the end circuit design the changes can be surprising. Your real world calculations could be accurate for the application. Though you didn't expand on the calculations, I'll trust you. After doing the research I've opted out on that one but you're right, it is a pretty simple minded thing to work with. I also just couldn't bring myself to carry a DMM around with me.

I hope you didn't have to completely replace your bigblue evercool mod circuit but if you did, at least you had spares on hand. I think you'll be very pleased with it after your prior experience once you have it going.

 

[Ruppy]

That sounds probable. The circuit used for the data sheet got better results but once a more expanded circuit is applied the results usually change and depending on the end circuit design the changes can be surprising. Your real world calculations could be accurate for the application. Though you didn't expand on the calculations, I'll trust you. After doing the research I've opted out on that one but you're right, it is a pretty simple minded thing to work with. I also just couldn't bring myself to carry a DMM around with me.

I hope you didn't have to completely replace your bigblue evercool mod circuit but if you did, at least you had spares on hand. I think you'll be very pleased with it after your prior experience once you have it going.

I actually have the day off so I am hoping to get something working today Once I do I will shine her up and start a thread

 

[rchriste]

I actually have the day off so I am hoping to get something working today Once I do I will shine her up and start a thread

I'm looking forward to following you there. Good luck on todays work.