Dangerous Regulators?

[Rocketman]

Question about regulators.

I'm full of questions.
Back when I was actually working, not sitting on my .... in front of a computer I used to design and build electronic stuff.
3 terminal Integrated circuit regulators were "New".
And now we have ultra low dropout regulators, cool.
These have built in shut down for over temperature, over current, short circuit, short people, but lack one thing: shutdown for low input voltage.
The ones I used to play with had a problem that may be a problem for e-cigs.

Which of the NEW regulators out there will shut down when the input voltage is lower than output+dropout? (huh?)
Example:
6v in 5.0000v out
5.8v in 5.0000v out
5.5v in 5.0000v out
cool so far
5.2v in 4.7592v out
5.0v in 4.5321v out
uh oh
4.5v in 4.0001v out
4.0v in 3.5432v out
low vapor
3.5v in 3.0021v out

This does not seem like a good thing.
When do these just stop sucking from the batteries?
Or do they?

Rocket

 

[BuzzKill]

The output can never be higher than the input !an LDO type regulator will maintain the differential voltage minimum , so as the battery dies the voltage drops as you see .

Dangerous ?? NO

safe YES .

you could just put a low battery indicator circuit in there a comparator of some sort.

BTW what regulator did you do these tests on , they are not all the same .

 

[Rocketman]

LDO type regulator will maintain the differential voltage minimum , so as the battery dies the voltage drops as you see .

Dangerous ?? NO

safe YES .

Buzz,
The IC type regulator will maintain the rated output if there is enough input voltage. If not enough voltage in it's tries like hell.
I don't believe it is safe to vape on a pair of batteries if one is below the minimum recommended cutoff.
The low battery indicator you talked about was for each cell or just the stack?
and is there a 3 or 4 terminal IC type regulator that doesn't act this way?
I think most do.
I still question the safety of a regulator that isn't smart enough to stop vaping before Blam.

Rocket

 

[BuzzKill]

Buzz,
The IC type regulator will maintain the rated output if there is enough input voltage. If not enough voltage in it's tries like hell.
I don't believe it is safe to vape on a pair of batteries if one is below the minimum recommended cutoff.
The low battery indicator you talked about was for each cell or just the stack?
and is there a 3 or 4 terminal IC type regulator that doesn't act this way?
I think most do.
I still question the safety of a regulator that isn't smart enough to stop vaping before Blam.

Rocket

If you just use regular batteries with NO regulator you have the same situation correct ? , the regulator will actually make you change batts faster because of the excess drop in voltage !.

You could make a voltage indicator for the stack or single cell, Over discharging a Li-ion batt is not a good idea , it lowers the life and in extreme cases can cause problems ( see the battery university site )
I have been using the AW 16340 's and when they get low there is NO DOUBT about it

I use a 5 terminal regulator that is designed for battery applications with reverse voltage protection , over temp over current etc.

Quote ]
Lithium-ion typically discharges to 3.0V/cell. The spinel and coke versions can be discharged to 2.5V/cell to gain a few extra percentage points. Since the equipment manufacturers do not specify the battery type, most equipment is designed for a 3-volt cut-off.

A discharge below 2.5V/cell may put the battery's protection circuit to sleep, preventing a recharge with a regular charger. These batteries can be restored with the Boost program available on the Cadex C7000 Series battery analyzers.

Some lithium-ion batteries feature an ultra-low voltage cut-off that permanently disconnects the pack if a cell dips below 1.5V. A very deep discharge may cause the formation of copper shunt, which can lead to a partial or total electrical short. The same occurs if the cell is driven into negative polarity and is kept in that state for a while.

Manufacturers rate the lithium-ion battery at an 80% depth of discharge. Repeated full (100%) discharges would lower the specified cycle count. It is therefore recommended to charge lithium-ion more often rather than letting it discharge down too low. Periodic full discharges are not needed because lithium-ion is not affected by memory.

 

[Rocketman]

Good info buzz,thanks.
You are correct that two batteries without a regulator puts you in the same situation.
There are folks that vape 5 volts, 6 volts, 7.4 volts.
The "most equipment" phase in your post applies to commercial electronic equipment, including factory e-cigs. Not most MODS. They are designed to be cutoff by the biological apparatus on the other side of the cartridge.
Discharging hazards not charging hazards are probably just as important to someone vaping a StackBattery MOD. The reported fires on youtube with LIpo packs being overcharged don't account for the e-cig mods blowing up in peoples faces and pockets.
And even UNPROTECTED Li-ion cells can be charged in a PROTECTED charger.
I'm just not a proponent of using a stack of unprotected Li-ion cells.
Thanks for providing the technical information.

Rocket


What is the input/output voltage transfer look like for the 5 terminal regulator you use?
How low does it go before it quits sucking juice from the battery?

 

[Charged]

For a single battery regulator the TI PTN04050C drops out at 2.95V. I mean it no longer puts out voltage. So the user knows for sure the battery is done. Have had no issues with draining batteries down to where they are dangerous.

 

[Rocketman]

That is actually a great way to go.
Big single cell and a boost regulator.
It knows when to stop. Most linear regulator don't.
If somone wanted to safely vape at 5 volts,
that would be one way to do it.
But what is the total power available with one 2600mah 3.7 volt cell
compared to 2 1000mah 3.0 volt cells?
Oh wait, the single cell actually has more power to start with.
Making 5 out of 3.7 just might be better than making 5 out of 6.

Rocket

 

[BuzzKill]

Rocket in my applications I try to use protected batteries , Right now I am using unprotected batteries ( AW16340's ) and have had no problems.
I will look into this further , when my batts are close to done ( or discharged ) I will test the voltage to see what it is .

OK 1 was at 3.44v the other was at 1.95v ! I am not sure if it was the top or bottom battery ( didnt check )

I'm sure a discharge controller ( like in the protected batteries can be incorporated as well. )

I have looked at the boost circuits , they require alot of components and are noisy but that does not mean they are not a viable solution.

 

[Rocketman]

Buzz,
Me too. I have a few "sample" boost chips and just don't have the time to mess with them right now. A single 18650 is fine for me.
The point I'm trying to get across (not for you) to those that would continue to blindly suck on a MOD after vapor goes down are asking for trouble.
16340 cells can be checked with a voltmeter after vaping a while to see what the voltage is at maybe about half charge. Both cells should match.
The 3.0 volt cells with the hidden magic chip will check 3.6 with a voltmeter. I think it is difficult to match capacities with used 3.0 Li-ion cells.
I think these are the ones that
"have a surprise in every box"
and a regulator just might be one way of finding it.
Rocket

 

[BuzzKill]

A super simple Low batt. indicator would be easy to implement , use a V ref and setup a comparator circuit to an LED.
I was just looking at a Maxim Boost IC the MAX631. with low batt. circuit built in !

Or one of these !
http://datasheet.sii-ic.com/en/voltage_detector/S808XXC_E.pdf

 

[Rocketman]

These are my comments removed from another thread to here, I sort of ended up hijacking someones else's thread.
The topic was Master Switches as a sure-fire (sorry) safety feature.
And some mods that have them, and some that don't, both homemade and commercial.
Mods with power consuming electronics, and power on LEDs,
need a master switch (or automatic power off circuit) to turn the electronics off or the battery will be drained without you knowing it. Bad news.

The master switch ideaas a safety feature, while a good concept still depends on the human to make it work. Let me tell you that what seems simple in your mind will not be simple to a lot of people. some have trouble running a 901 manual. Is the battery dead?
A mod left on, or accidentally turned on, may continue to discharge the battery to below a safe level without you knowing it. Some circuits draw some power doing nothing.
Master switch left on - same as not being there, it's now effectively a One Button MOD. People leave coffee pots on while on vacation, leave kids or pets in cars. Old people forget all kinds of .... (is sort of nice meeting new people everyday though).
I have run into people that have trouble operating a new factory e-cig.
Or people that aren't sure what battery will fit in their mod, or which direction to put it in.
Or those that think, oh heck, you get the point.
People complain if the little vape button hurts their little fingers and want something easier to press. Master switch is a good concept, but people will adapt to ignore it and leave it on between vapes if they think it is inconvenient. Then forget and go some place else. I know of one dual switch mod that blew in someone's pocket. And read about one that it wouldn't have mattered how many switches it had, it blew on the inhale.
Guaranteed safety? It'll take more than a switch to do that.
Safety feature? maybe. But for regulated stack battery mods with power consuming electronics and LEDs, a necessity.

Rocket

"Don't drink and vape, and if you do drink, let someone else vape for you"
"Buzz vaping IS drunk vaping"

 

[thorn]

I'll agree that some people would simply CHOOSE to ignore the extra safety of a master switch and leave it on but there would also be those who would prefer a master switch to help prevent accidents while traveling or not in use periods. This master switch would be directly in-line with the push-to-vape switch people use now. To leave the master switch on would not complete the circuit in any way by itself, that would defeat the purpose. I saw one mod (forget which one) that had a twist master switch feature, seemed kinda neat.