Adjustable voltage box mod

[bigblue30]

Here are some pictures and a circuit diagram of my mod. It is an adjustable voltage mod. This is my very first attempt at a mod. The next one will be much cleaner.

Feel free to ask any question.

This circuit below will accept any voltage from 2.8 volts to 9 volts and it will output from 1.22 volts up to (the input voltage -.45 volts at 3 amps). On a freshly charged set of 14500 batteries with a 2.2 ohm load I was able to adjust the output from 1.2 to 6.75 volts. One full turn of the resistor is about .2 volts. I find that 4.3 is just right for my carto

The TI UCC383-ADJ has some nice features for use in a mod:
0.45 V Dropout at 3 A
Standby Current Under 650 ua
Short-Circuit protection
Thermal Shutdown
Reverse Battery Protection

The main parts are:
1- TI UCC383-ADJ 5 pin regulator
2- 10uf 10 volt Tantalum capacitors
2- 14500 batteries
1 – 200k .5 watt variable resistor
1 – atty or carto connector (the one in the picture is using a D-1 connector)
1 – 3XAA battery holder with built in switch (on my next one I will replace that switch with a better 3 amp switch.
1 – 5 hole X 7 hole PCB

Other optional parts are:
2 – LEDs (One to show when the main switch is on and one to show when voltage is going to the connector.
2 – Resistors for the LEDs
1 – N/C .5 amp push switch (used to turn on the connector on after the main switch is on)

Below is a picture of the insides. Notice the big red switch… I used such a big switch because I had the room and also I liked the feel of the larger button. I also like the button on the side and I use it with my index finger. To me this was just a more natural feeling. Below the regulator is a large socket that holds the LED. On my next one I will put a heat sink where the LED socket is.

Here you can see the 200k variable resistor that is used to adjust the voltage.

In the picture below you can see the voltage is 6.57 volts. That is into a 2.2 ohm resistor. I did not want to try this with a real carto because I thought the carto would fry with that voltage. That works out to around 2.99 amps. That little 5 watt fixed resistor was”hot” but the reg did not shut down. It does have a built in thermal protection circuit. I am sure that if I left it running much longer it would shut down. My next one will have a heat sink under the chip.

As you can see, that switch and the LED holder take up a lot of room.

 

[quynhwil]

cool. I want one like that. All I need is a capacitor and an adjustable regulator and wriring instruction. Thanks good job. QUYNH

 

[roadrash]

Ya, nice one Blue, pretty neat to. Need to have a little experience with soldering and modding to build this one. i have also found that the 510 cartos work well in the 4.3 to 4.5 volt range. 5v, just to hot and not much taste.
I,ll have to put this one on my list.
thanks for posting.

 

[bigblue30]

Ya, nice one Blue, pretty neat to. Need to have a little experience with soldering and modding to build this one. i have also found that the 510 cartos work well in the 4.3 to 4.5 volt range. 5v, just to hot and not much taste.
I,ll have to put this one on my list.
thanks for posting.

Thanks, I guess being a EE for a few years helps. This really is my first mod ever.

I also want to thank you , Buzzkill, Roadrash,WillyB, and Switched for your feedback.

 

[roadrash]

Thanks, I guess being a EE for a few years helps. This really is my first mod ever.

I also want to thank you , Buzzkill, Roadrash,WillyB, and Switched for your feedback.

O ho, I'm not done yet. If you have a 200k variable resistor to adjust the voltage, what is the voltage regulator used for?
Are there no adjustable voltage regulators?
i hope the answer is not to far over my head.

 

[bigblue30]

O ho, I'm not done yet. If you have a 200k variable resistor to adjust the voltage, what is the voltage regulator used for?
Are there no adjustable voltage regulators?
i hope the answer is not to far over my head.

Think if it like a water spout with a valve on it. When you turn the spout "left and right" you are regulating the water that comes out of the hose. If the water pressure drops……someone turns on the dishwasher…. You would have to turn “up” the valve to keep the same amount of water coming out….correct?

Most un-regulated mods are like that. They are set to allow 5 volts to come out…..As long as the input is greater than 5 volts….They will turn the valve up and down to keep the voltage coming out at 5 volts……But that is all they can do…..Give you 5 volts all the time.

In my circuit... It takes in the battery voltage 7.2 volts and outputs it from 2 to 6.5 volts...I thought I just said that the regulator wants to put out 5 volts all the time?

That is where the variable resistor (VR) comes into play. Adjusting the VR up or down “sets” that output voltage from the regulator. By turning the VR, you can set the output (2-6.5 volts) using pin 4 and 5 for your “sweet spot”. Once set, by the VR the regulator will keep that voltage until the batteries get low.

So in my circuit I use a very small (1/2 watt) VR to control a larger voltage and a larger current. Up to 3 amps in my circuit.

So to answer you question....There are adjustable voltage regulators, but they still need something to make them adjustable. In this case a VR.

 

[roadrash]

OK, I read it 10 times and i still got lost turning the water valve.
just kidding, actually I got it to were most mods come in 7.4v and leave the resistor @ 5v.
if my brain has wrapped around this schematic, if I had a 5v supply, I would not need the voltage regulator?
thanks for taking the time Blue.

 

[nicotime]

Roadrash...the adjustable voltage regulator output is usually controlled by a resistor...one value resistor makes the AVR put out say 5 volts...another value makes it put out 4.5 volts...but if you wanted to change the voltage you would have to change resistors every time...UNLESS you use a variable resistor instead which you can change the resistance by turning a screw. The variable resistor cat be used by itself because its not meant for that amount of current. Hope that helps a little...like BB30 said just said differently. Correct me if I'm wrong BB30.

If your into cars...the AVR is the carb..and the variable resistor is the idle adjuster screw. LOL

Very nice build also BB30!

 

[bigblue30]

OK, I read it 10 times and i still got lost turning the water valve.
just kidding, actually I got it to were most mods come in 7.4v and leave the resistor @ 5v.
if my brain has wrapped around this schematic, if I had a 5v supply, I would not need the voltage regulator?
thanks for taking the time Blue.

Just to be clear....NO voltage from the resistor leaves the circuit and goes to the atty. The resistor only controls the requlator..all the voltage to the atty comes only from the regulator.

About the 5 volt power supply. If all you wanted was 5 volts and only 5 volts to your atty then a 5 volt PS would work. You would using batteries or a cord that was plugged into the wall.

And to twist the water value some more .....The only way you could have a 5 volt supply is to use batteries that add up to exactly 5 volts, or buy or make a 5 volt supply. In this case you would have a circuit very much like mine inside of it already.

 

[bigblue30]

Roadrash...the adjustable voltage regulator output is usually controlled by a resistor...one value resistor makes the AVR put out say 5 volts...another value makes it put out 4.5 volts...but if you wanted to change the voltage you would have to change resistors every time...UNLESS you use a variable resistor instead which you can change the resistance by turning a screw. The variable resistor cat be used by itself because its not meant for that amount of current. Hope that helps a little...like BB30 said just said differently. Correct me if I'm wrong BB30.

If your into cars...the AVR is the carb..and the variable resistor is the idle adjuster screw. LOL

Very nice build also BB30!

You are correct....Sorry I started to answer RR and had to leave before I finished it....When I hit post I saw you already did.

 

[roadrash]

Thanks BB30 and Nico, I finally got it. i think.

I think most of my confusion came from thinking the Volt Reg had a constant voltage output, no matter the input.

in summary, the variable resistor sends control voltage ( the amount of voltage the Volt Reg is to put out) to the voltage regulator. The Volt Reg then sends this amount of voltage to the device.

the nc device switch sends supply voltage to the variable resistor. where as it does not carry the whole load, it can be a low amp switch.

Thanks again guys, hopefully I got it this time.

 

[bigblue30]

RR, Cool, You got it.

Part of the confusion is because most of the mod's you see out there are "fixed" output. You put a voltage in like 5 to 8 and you always get 5 out.

This is what is so different about mine...you put in 5 to 8 volts and you can "chose" what you want it to put out with the variable res.

 

[bigblue30]

This the second one. It it amazing how much you learn by building the first one.

I wanted to see how small I could get it.

Built in heat sink.

New button that replaces the N/O (arm switch) and the N/C (Fire switch).
It is both in one.

No need for the built-in case switch. The new one takes care of that.

 

[roadrash]

Whoa BB, That is small and neat. Nice job M8tie. I would love to do that. I dont even know how to order the parts. Is the width and height about 1/2'' or less? I am wondering if I could stand it on end inside my 3/4 '' Copper top mod or a flashlight mod?mmmmmmmm if I can get the parts, I may need some help putting it together.

ps: can you explain the switch a little more?

 

[bigblue30]

More pic for RR:

 

[bigblue30]

ps: can you explain the switch a little more?

RR,
I have had a lot of questions about my switch setup, most from e-mail. I will try to explain it here. If it is not clear please let me know.

If you look at the TI UCC383 or 283 or even the MV NCP5666. You will see that the control pin is used to turn the chip off by sending it to ground…..open the pin or send it high and it will turn on. That sounds back wards…but that is how it works.

I had 4 ways of wiring my mod:


1. Have a single 3 amp “fire” switch in the battery line and do not connect the control pin. You then have a single switch that activates the device by turning on the battery. There is nothing wrong with doing it this way. The only problem is if the single switch shorts (I know that 99.99999999999% of the time the switch will fail in the open.) the only way to turn it off is to pull the battery, not really a problem in a box mod, but if you have a very fine thread…many turn….battery cover….. it could be a problem.

2. Hot wire the battery to the Vin and only use a small amp switch connected to the control to fire the reg …I am sure that you agree that this is NOT a good thing to do. Voltage would always be flowing….milli amps.

3. Have a high quality ‘kill” switch and a separate high quality “fire” switch. This makes it very “safe”. Both switches have to fail to get a miss fire. The kill has to short and the fire has to open. I know nothing is fool proof. This is as fool proof as possible with this chip, This is the belt and suspenders one.

4. Have a single switch that does both jobs in one package, and still be safe. I do not like the idea of having 2 switches, or having to remember to turn the kill switch off to make it safe.

At rest with this switch...the kill has the battery circuit open and the fire is shorted to ground.

My switch has a N/O and a NC switch built into one package.


……is that the men in the white coats at the door coming to take me away..

 

[WillyB]

Simply lovely. It's nice to see the high level of thought and planning that went into your mod. No skimping on parts, no semi-similar RS components. The heat sink, the proper caps all nicely soldered.

1. Have a single 3 amp “fire” switch in the battery line and do not connect the control pin. You then have a single switch that activates the device by turning on the battery. There is nothing wrong with doing it this way. The only problem is if the single switch shorts (I know that 99.99999999999% of the time the switch will fail in the open.) the only way to turn it off is to pull the battery, not really a problem in a box mod, but if you have a very fine thread…many turn….battery cover….. it could be a problem.

I don't know if that's entirely accurate. When using a switch to enable power from the battery to the reg a normally open switch is used. Most of the reported switch complaints/failures seem to one of activation. Early indicators of a problem are the need to press much harder.

That said your approach is well thought out. Being old school I still use the 'loosen atty' method as a matter of habit.

Nice work.

 

[bigblue30]

WB,
I know that sometimes my explanations are difficult to understand, but please look at again at what I posted and let me know what's not correct.

You said “I don't know if that's entirely accurate. When using a switch to enable power from the battery to the reg a normally open switch is used. MOST of the reported switch complaints/failures seem to one of activation. Early indicators of a problem are the need to press much harder.”

I said…."The only problem is if the single switch shorts (I know that 99.99999999999% of the time the switch will fail in the open)." And said “the only way to turn it off is to pull the battery” Perhaps I didn't word that exactly correctly (I know it can be difficult to follow the info in the parenthesis).

This means that most of the time …..99.9999999999% the switch will be hard to push…..Will not make a connection…

I agree..Most of the time the switch will fail in the open state. BUT .0000000001% of the time it will fail in the closed state.

What IF the switch fails in the closed position after you hit it, put it down and leave the room...or you leave it on the seat of your car? It will continue to "heat" until you have a fire or the batteries die. I'm just sayin'. You've been a huge help to me, so please let me know your thoughts at any time!

 

[misterD]

can i use the TI booster with a POT or variable resistor? and if yes could someone give me a link for it? i was searching for it on digikey but couldn't find it.

 

[bigblue30]

By booster you mean 3.7 in and more then that out?

If yes...it is here:
Plug-in Power Modules - Non-Isolated POL - PTN04050C - TI.com

FYI....look on the right side under ....sample.

Swap out the fixed resistor for an variable one and you are all set.