What constitutes a "pulse"?

[multicam]

Hey all,

My account is new here but I've been lurking for months now. This is my first topic. Sorry if this has been brought up before but I just wanted to get some fresh impressions.

I've read a lot about batteries and how their max amps advertised may not be for continuous draw of power, but rather for a quick pulse. Where exactly is the line between a pulse and a continuous draw? For our purposes, say you take a 3-second draw. Did that count as a pulse?

Thanks for your help!

 

[edyle]

More like 1 to 100 milliseconds I imagine.

The high pulse is usefull for electric motors where you get an initial high pulse of current for what can be described as an instant but once the motor rpm gets up in speed the back emf causes the amp draw to be much reduced.

 

[multicam]

Thanks edyle, that makes sense. The max amps shouldn't even be advertised then at least when selling batteries to vapers.

 

[Dampmaskin]

The max amps shouldn't even be advertised then at least when selling batteries to vapers.

Agreed.

 

[AXIOM_1]

Thanks edyle, that makes sense. The max amps shouldn't even be advertised then at least when selling batteries to vapers.

Continuous current is just that....continuous

Whenever a sudden voltage is applied to a coil then a current pulse is generated. The current pulse is caused by a property of the coil known as inductance. The inductance of a coil will produce an inverse electromotive force that is in direct opposition to the applied voltage. This will cause a high initial current pulse/spike but that will rapidly disappear.

As for vapers, you mainly need to be concerned only with continuous current output rating of a battery as the peak output rating is not near as applicable in vaping devices.

 

[Completely Average]

There once was a time where manufacturers followed standards. Back when they did a pulse was anything less than a 30 second discharge.

Of course these days manufacturers (And especially rewrappers) do not follow standards, so a pulse is whatever they want to claim it is.

 

[Mooch]

Agreed here too.

"Pulse" ratings for batteries are useless unless a lot more information is given with the rating. And even then there's no standard for everyone to use so different people could give different pulse ratings to the same battery.

We don't know how long the pulse was, how often the pulse was used, how hot the battery got (which has a big impact on battery life), and whether the battery would be unsafe if the mod accidentally got stuck on (autofiring or button gets pressed in a pocket, etc.) using a coil resistance that drew the pulse current rating.

@edyle's mention of 1-100 milliseconds is much closer to what I considered a "pulse" until I started vaping.

 

[MacTechVpr]

There once was a time where manufacturers followed standards. Back when they did a pulse was anything less than a 30 second discharge.

Of course these days manufacturers (And especially rewrappers) do not follow standards, so a pulse is whatever they want to claim it is.

Hard to tell what's authentic anymore much less standards.

(I guide myself by a generic normative standard of 10 sec's max.)

Good luck all.



p.s @edyle I understand 1/100 is about the max threshold of human detection (in time).

 

[AXIOM_1]

I was usually paranoid unless my oscilloscope showed me a train of pulses of 72 pulses per minute

Yep, pulse ratings are pretty much moot for the average vaper. The OP just needs to forget about battery pulse ratings or inductive circuit pulses and stick with continuous current ratings.

 

[suprtrkr]

As has been said, there's no real standard. I personally think of a "pulse"-- dating back to my electrician days all those decades ago-- as "half a cycle." This, obviously, applies only to alternating current. Given our 60 cycle standard in the US, that would be 1/120th of a second or less; that is, somewhere short of 10 milliseconds. But (most) vape gear is DC-- it doesn't have to be, it just is because it's powered by batteries-- and "cycles" would not apply. (No reason you couldn't make a vape wand tethered to a power supply fed by wall socket juice, and this could be either at the atomizer, but that's a question for another thread.) For vaping purposes, and for safety's sake, consider only the CDR or continuous rating. You never know when you'll get a stuck button, or get stupid and set it down without setting the lock ring, or the electronics will fail high. Taking the risk is... risky.

 

[suburbiansam]

Be careful where you buy your batteries. Most of the "fire" batteries are rewraps of cheaper, less reliable batteries. Stick to LG, Samsung, Panasonic, or other major battery brands. These mfr's generally list continuous amperage rather than pulse. as has been said above, pulse is irrelevant for vapers, and is merely an advertising gimmick to make the batteries seem better than they really are. There are verified vendors of batteries in the forum. Please take a look and don't be afraid to spend $10-20 for pair of good rechargeable batteries.

 

[philoshop]

Everything that 'currently ' needs to be known about vaping batteries is best found right here at ECF. Ratings, numbers, etc.
@Baditude, @Mooch, and a few others (sorry folks for any exclusions) know more about the vaping battery suitability issue than even the people who manufacture, sell, or resell, those batteries. Listen and pay attention to what they say, and you'll stay out of trouble.

 

[multicam]

Thanks for the replies everyone. I've always known to ignore the pulse rating and focus on continuous, I was just curious as to what exactly constituted a pulse. Good info

 

[AXIOM_1]

Thanks for the replies everyone. I've always known to ignore the pulse rating and focus on continuous, I was just curious as to what exactly constituted a pulse. Good info

The trouble with the term "pulse" is that it can pertain too many things in the electronics industry. Another problem is that manufacturers tend to throw the term around loosely and use it instead of the term "peak".....

As you probably assume, any type of pulse rating is not meant to refer to a constant and unchanging value. Batteries can deliver a certain amount of continuous and constant current without failing/damage.... But batteries can also deliver higher amounts of current than the continuous current rating, it's just that the battery cannot deliver the higher current for very long of a period of time without the battery becoming damaged... In order for a battery to deliver greater current than it's continuous rating then it can only do so for very small brief periods of time so that the battery doesn't become damaged. These small intervals of time in which higher amounts of currents are being delivered are pulses.

 

[stevegmu]

One press and release of the button-same as with a blender...

 

[MacTechVpr]

A Guide to Understanding Battery Specifications

This question comes up time and again. And I've probably heard the answer a half dozen times failing to note who said it or ask for a source. Here's the MIT Electric Vehicle Team's...A Guide to Understanding Battery Specifications which differentiates the standards for maximum continuous and maximum discharge pulse currents in this short glossary of definitions. Hopefully this thread will help.

Good luck all.

 

[Robert Cromwell]

A Guide to Understanding Battery Specifications

This question comes up time and again. And I've probably heard the answer a half dozen times failing to note who said it or ask for a source. Here's the MIT Electric Vehicle Team's...A Guide to Understanding Battery Specifications which differentiates the standards for maximum continuous and maximum discharge pulse currents in this short glossary of definitions. Hopefully this thread will help.

Good luck all.

Do you suppose the battery companies are following that 30 second pulse specification?

 

[MacTechVpr]

Good question. I would expect the (electrical) standard is international. But I wouldn't know what body "officially" controls the spec. It's not a UL standard don't believe. The chemistry is controlled by international hazardous materials covenants.

(With China and re-skinners it's anyone's guess as was noted earlier.)

Perhaps someone with more expertise will chime in. G'luck.

 

[edyle]

Do you suppose the battery companies are following that 30 second pulse specification?

Note that that is from "MIT Electric Vehicle Team's"; it is for vehicle batteries.

 

[Mooch]

Thanks for the link!
The pulse rating they use though is tailored specifically for testing automotive batteries. Each industry/field-of-interest will have their own pulse rating. I've encountered ratings from 100mS to 60 seconds. And I haven't seen even a mention of what the pulse width and duty cycle standard could be for vaping batteries, or the max allowed temperature. The battery manufacturers don't even have pulse ratings and, to my knowledge, there aren't any US/global safety standards for pulsed discharges.

In my opinon a pulse rating for vapers can be set three ways, after selecting a pulse time and a rest time, i.e., the "duty cycle"....

1. Find the max pulsed current at that duty cycle that will not vent the battery. This typically leads to very high ratings, often seen with 20A batteries having 80A and higher pulse ratings. But it's done at the expense of safety. If there is a problem with the mod, auto firing or a stuck mech mod's button, then the battery will most likely vent. Or possibly worse.
2. Find the max continuous current that will not vent the battery and use that as the pulse rating. This will be higher than the battery's CDR but low enough to hopefully protect the vaper if the mod malfunctions or gets stuck on. Testing for this rating would have to include destructive testing of the battery, several of them, to find the temperature/current level at which they vent.
3. Find the max continuous current that will cause a temperature rise as high as is reasonably safe, perhaps between the point of the onset of thermal instability (about 80°C-100°C)and where internal components start to melt (120°C-130°C). This results in a lower pulse rating but gives a bit of a safety margin for the vaper. Unknown variables like another hot battery next to it or a very high ambient temprature won't endanger the vaper as much as a rating derived by method #1 or #2.

ECF is a huge worldwide forum. We could actually set a standard here. But, no manufacturer will use it. And no rewrapper will either as their battery ratings would plummet. I have a standard for my own testing, but I think we'll never see a standard set. Or even multiple standards.