Question and problem with 5v regulator

[Scott Tenorman]

Hello everyone, I built a mod out of a 3AA battery box using this schematic:

With most of my 510 attys (2 different sources) I only get about a 5 second draw, then the power cuts off to the atty. I have to turn the main switch off then back on and I get 5 more seconds of draw. With a couple attys it works flawlessly, sometimes indefinitely sometimes for just a while and then back to the old off/on routine. I have tried a 10 uF capacitor across all combinations of pins on the 5v regulator to no avail. Can anyone explain this problem and how to fix it? Thanks in advance

 

[Shortstuff116]

I just started building my own 5V mod using the parts I got from madvapes and I'm following the instructions posted here. Read all 4 pages and see if this doesn't help you out. You'll notice the additional of the 10mf capacitor in their wiring diagram.

I already wired this together on a breadboard and ended up with 5.4 volts on the output, but I won't know how well it works until I put this together and try it outright.

Just to clarify your pin numbers:

Pin #1 - Votlage In
Pin #2 - Voltage Out
Pin #3 - Ground
Pin #4 - Control (disable)

Hope this helps!

 

[hoogie76]

I'm finding that the atomizers that give the 5 second draw are usually 2.5 ohms and the ones that work are 3.2+ ohms. I did another 5 volt mod last night and tried both the 2.5 ohm and 3.4 ohm and it worked on both..

 

[cpcp68]

what type of regulator are you using?

Edit: never mind. I think I found it at madvapes (3A 5V LDO)

best guess, if your batteries are protected, the protection may be kicking in as you may be drawing 2A with a low R atty. hoogie is right.

 

[bigozone]

what type of regulator are you using?

Edit: never mind. I think I found it at madvapes (3A 5V LDO)

best guess, if your batteries are protected, the protection may be kicking in as you may be drawing 2A with a low R atty. hoogie is right.

i second that oppinion.... sounds like protection circut on batteries kicking in because they see the power drain at exceedes the protection circut's built in triger points. or possibily the protection circut sees the masive power drain and thinks it is a short circut (which an atty is BTW).

maybe that's why i use non protected CR2s,,, but i don't recommend it for others!!!!

 

[four2109]

OK, so help me make sense of this... What atomizer are you using that would make the difference, or battery, or whatever...?
Just asking because mine works fine on 401, 4081, 510, 801, 901, KR808...

 

[Wall]

Need you to post what batteries you are using I think. Look up the specs on them, if it is protected and cutting off due to you drawing too much current through them, that could be it.

Going to a HV atty would help but you would get less power out of it.

 

[Scott Tenorman]

Sorry for the late reply everyone, I am using 14500's and I am certain that I am activating the protection circuit. I have tried several different 10uF capacitors between pins 3-4 before the atty, after the atty and everything in between with no kind of consistent results. Still reaching the 5sec cutoff. Is there some special place in the circuit to put the cap? I'm not an electronics noob by any stretch, I am just totally baffled by this at this point. Thanks

 

[cpcp68]

The cap is really for the regulator. Sometimes they become unstable without caps. Usually, one between input and ground and one between output and ground are recommended. Check the datasheet for your regulator for proper values.

 

[Scott Tenorman]

It seems like there is no way to prevent the 5 second cutoff except with a high resistance atomizer. The capacitor is only to keep the current coming out of the regulator even, which the regulator does a pretty good job of by itself. I'm gonna see if I can add a very small ohm resistor in series before the atty so that every atty I put on it will have the required resistance to not trigger the protection of the batts.

 

[cpcp68]

or you can try larger capacity batteries. make sure your resistor takes whatever power you dissipate in it.

 

[jace]

I find myself very interested in how this thread turns out!

 

[WillyB]

I'm finding that the atomizers that give the 5 second draw are usually 2.5 ohms and the ones that work are 3.2+ ohms. I did another 5 volt mod last night and tried both the 2.5 ohm and 3.4 ohm and it worked on both..

Well that makes the regulator pretty much unacceptable for anyone using Joye 510's. Mine usually come in at about 2.2-2.3 ohms.

I'm gonna see if I can add a very small ohm resistor in series before the atty so that every atty I put on it will have the required resistance to not trigger the protection of the batts.

Well that will change the current available to the atty, lowering the atties WATT's and shortening the battery's runtime.

@ Scott

What kind of loaded voltage are you actually getting with the atties that cut off (which I assume are Joye)? From the other post I see this:

I'm taking that to mean that anything over 5.5v gets regulated down to 5.5v

 

[cpcp68]

Well that makes the regulator pretty much unacceptable for anyone using Joye 510's. Mine usually come in at about 2.2-2.3 ohms.

I think the regulator is fine @5V. The batteries seem to be the problem

 

[cpcp68]

Also, just for your information, I found this paragraph on the datasheet of a 3V, 680mAh RCR123A. It is about the internal protection circuit. The cutoff for these batteries is about 1.8A discharge current. I guess your 14500s may even be less (provided they do have a protection circuit inside).

 

[WillyB]

Well that makes the regulator pretty much unacceptable for anyone using Joye 510's. Mine usually come in at about 2.2-2.3 ohms.

I think the regulator is fine @5V. The batteries seem to be the problem

Which batteries? Are you saying the OP has a bad batch or brand? Folks have been building 5V box mods here for quite a while. They have used pairs of 10440s, 14500s, and 18650s. I would say the bulk, actually almost all, of these have been protected UltraFire or TrustFires with the TI 5V regulator. Whenever folks post pics that's all you ever see. Some of the original examples have been from some very savvy and well regarded modders. As far as I can tell this is the first time this issue has come up. I assumed at first some OP wiring problem, but Hoog himself has duplicated the results. Maybe a bad batch of regulators?

I've seen your posts before, they always seem to be theoretical in nature. You said:

The cutoff for these batteries is about 1.8A discharge current. I guess your 14500s may even be less (provided they do have a protection circuit inside).

So theoretically using your 1.8A number the most volts folks could use before triggering the protection circuit with a Joye 2.3 ohm atty is about 4.2V. In the real world I'm sure many folks have easily exceeded that.

Asking for the actual loaded voltage of the MV regulator is a valid question, for if in fact it is 5.5V that would theoretically explain why it's unacceptable for Joye atties. The current required to drive a Joye atty at 5.5V would be about 2.4A.

 

[Scott Tenorman]

Which batteries? Are you saying the OP has a bad batch or brand? Folks have been building 5V box mods here for quite a while. They have used pairs of 10440s, 14500s, and 18650s. I would say the bulk, actually almost all, of these have been protected UltraFire or TrustFires with the TI 5V regulator. Whenever folks post pics that's all you ever see. Some of the original examples have been from some very savvy and well regarded modders. As far as I can tell this is the first time this issue has come up. I assumed at first some OP wiring problem, but Hoog himself has duplicated the results. Maybe a bad batch of regulators?

I've seen your posts before, they always seem to be theoretical in nature. You said:
So theoretically using your 1.8A number the most volts folks could use before triggering the protection circuit with a Joye 2.3 ohm atty is about 4.2V. In the real world I'm sure many folks have easily exceeded that.

Asking for the actual loaded voltage of the MV regulator is a valid question, for if in fact it is 5.5V that would theoretically explain why it's unacceptable for Joye atties. The current required to drive a Joye atty at 5.5V would be about 2.4A.

I assure you there is no wiring problem. I know for sure that the problem is that an atty with 3 ohms give or take doesn't have enough resistance and the current being pulled goes over what the batteries are designed to give and the protection kicks on in the batts. HV attys have a higher resistance for this very reason. There isn't a problem with the batts, the regulator, or the wiring. It is all working exactly as intended. I'm just trying to make it so this circuit works with any atty, regardless of resistance.

 

[WillyB]

I assure you there is no wiring problem. I know for sure that the problem is that an atty with 3 ohms give or take doesn't have enough resistance and the current being pulled goes over what the batteries are designed to give and the protection kicks on in the batts. HV attys have a higher resistance for this very reason. There isn't a problem with the batts, the regulator, or the wiring. It is all working exactly as intended. I'm just trying to make it so this circuit works with any atty, regardless of resistance.

I'm not knocking you. It just seems odd that all of a sudden this problem appears. It wasn't too long ago that 510 meant only Joye 2.3 ohm atties. The first 5V TI regulator mods came out well before these 510 semi-clone, higher ohm atties made the scene. There have also been many, many flashlight mods using the TI regulator... again no problems like you reported.

HV attys have a higher resistance for this very reason

I don't believe that to be the case. The HV mods can run the Joye atties without the batteries resetting (at least I haven't seen reports that they do). It's the burnt taste and longevity that's the major issue.

But you may be right. With my AC powered 4.7V PT a 2 to 3 second pull is all I've ever attempted.

Hopefully some 5V mod builders will join in with some feedback.

 

[Scott Tenorman]

I'm not knocking you. It just seems odd that all of a sudden this problem appears. It wasn't too long ago that 510 meant only Joye 2.3 ohm atties. The first 5V TI regulator mods came out well before these 510 semi-clone, higher ohm atties made the scene. There have also been many, many flashlight mods using the TI regulator... again no problems like you reported.
I don't believe that to be the case. The HV mods can run the Joye atties without the batteries resetting (at least I haven't seen reports that they do). It's the burnt taste and longevity that's the major issue.

But you may be right. With my AC powered 4.7V PT a 2 to 3 second pull is all I've ever attempted.

Hopefully some 5V mod builders will join in with some feedback.

I'm with you WillyB, I hope someone more knowledgeable than I chimes in. This is really bugging me. Oh, and I tried a 10 ohm resistor between power out and the atty, that just reduced the voltage, so I tried it in between atty ground and ground and while there are still 5volts at the atty, I don't believe there is enough current to make it work. I'm going to try some 2ohm resistors when I get them in the mail.

 

[Ez Duzit]

Surprised this is happening when using two 14500's. I don't use 510 atty's regularly anymore, but I do use them for a little while whenever I build a 5 volt box. Basically it's my version of a stress test, since I know the 510's draw heavy current, and so far, I haven't seen this happen. Not even using two 10440's, (which is what I usually use), so it shouldn't be happening with 14500's. But, not every protection circuit is built equally. And sometimes even batteries bought at the same time, from the same supplier, don't perform the same.

Anyway.
Scott, are the batteries you're using brand new, or have you had them a little while? How many batteries do you have? Does it do this with all of them? Are they fresh off the charger fully charged, when it happens? Also, are they from a well known supplier, or just the cheapest price you could find? (ebay or DX, etc...)

Maybe there's only one problem battery causing it. The protection circuit kicks in on that one, and the whole thing shuts down, since the remaining battery can't power it by itself. Or if you do have a bunch of em, maybe a few of them have protection circuits with borderline (or even faulty) tolerances. I'm curious as to where they're from. Because the solution may be as simple as using batteries from a different supplier. Short of that, try a different regulator. Or try rebuilding the circuit with fresh parts and see what happens. If it still has the problem, then you definitely need different batteries.

BTW, have you checked the output voltage yet? Unloaded? Under load with atty attached?

You also mentioned putting a 10 ohm resistor into the circuit to lower the voltage, and said you're going to try 2 ohms next. But even a 1 ohm resistor will lower the voltage all the way down to about 3.5v across the [510] atty. You would need something as low as .33 ohms or even slightly less to maintain roughly 4.4-4.6v.

Anyway, that's my $.02 worth. But one thing I'm sure of. Two good quality 14500's shouldn't have a problem powering a 510 atty with this regulator. Otherwise we would see lots and lots of posts about it.