Bringin' back the 'Pulse vs Continuous' debate

[Ayloxs]

I just posted this in response to a statment about deciding how much current can be safely drawn from a given battery. I'm not normally one to double-post, but a misunderstanding of this can be dangerous, and it's kinda buried in another topic.

I read quite a few articles looking for the definition of the 'pulse discharge rating', yet none exactly explained it. I got plenty on 'pulse DC current' though, and this is what I'm getting out of it all.

Dupliacated post:
It is my understanding that the pulse rating for batteries is for a different type of operating enviornment entirely. For example, some LED flashlights use pulse current to achieve dimming, as opposed to decreasing voltage. The current and voltage remain constant, but the current is switched on/off quickly, with specific intervals between the pulses. To clarify, a 10-millisecond pulse per 100ms would result in 10% of the brightness of a continuous discharge of the same current/voltage. This is beacuse the final wattage being applied to the bulb is decreased, since it is only being energized for 1/10 of the time the that the switch is turned on. Higher-amperage pulse ratings are used as a maximum for these short bursts, however the average discharge (over time) should still not exceed the continuous rating of the battery.
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According to this logic, vaping would be an example of continuous discharge, regardless of the length of one's inhale. Now, I am not an electrical engineer or anything like that. I would love confirmation from anyone qualified, just the same as a solid argument proving me wrong. I figure it's better to err on the side of caution though, since we're dealing with potentially explosive equipment.

 

[WattWick]

The only other place I've seen references to pulse ratings is in the RC world. Like in helis that can pull quite a bit of power at rapid direction changes, 3D flying, etc. Not that any sane flier would gear their helis for burst ratings. Anyway, in that case it's very much a quick burst. Not rapid pulsing over time or any such. Never seen your interpretation of it. Now that I have I am ... confused and somewhat intrigued.

Edit: Removed some nonsensical early morning rambly stuff.

 

[rondasherrill]

Googling about the exact nature of what is meant when referencing pulse discharge doesn't uncover much that hasn't already been parroted on every vaping forum, but I did find these two articles that actually describe pulse discharge as more of a duty cycle type discharge, instead of the commonly thought short press of a button.

Battery Discharge Methods
http://www.dtic.mil/dtic/tr/fulltext/u2/a415407.pdf

 

[Verb]

I've been reading up a little on battery ratings. I was surprised to find that continuous ratings were not standardized. I knew the pulse ratings had very differerent testing standards, but no standard on the continuous rating was a shock.
The VTC5's 30A rating is max discharge while staying under 120 degrees C. The Samsung 25R and LG HE2 have a 20A rating but cut their test at 100 degrees C.

 

[Norrin]

As I understand it (not an expert) vaping for most would probably come under pulse use BUT why take any risks and do you really want to cause yourself a serious injury just to get a bigger cloud? I don't approach these figures myself Vaping at about 4.5A now and that is about my highest.

 

[WattWick]

I'll spend my allotted Stupid Question-A-Month quota just to get something clarified.

Burst rating? Pulse rating? Same same?

Is any of our gear even capable of these nanosecond pulse thingies? Seems that in order to achieve this "capacitor effect" it (ideally?) needs a fairly specific pulse rate?

 

[Dampmaskin]

Is any of our gear even capable of these nanosecond pulse thingies?

A mod that uses 800 Hz PWM, draws pulses of up to 1.25 milliseconds. There are probably other mods with higher frequencies, and many with lower ones.

My approach to the pulse rating thing, is to ignore the pulse/burst rating altogether. I stick to the continuous rating, since that one is at least a little bit better defined.

 

[WattWick]

A mod that uses 800 Hz PWM, draws pulses of up to 1.25 milliseconds. There are probably other mods with higher frequencies, and many with lower ones.

My approach to the pulse rating thing, is to ignore the pulse/burst rating altogether. I stick to the continuous rating, since that one is at least a little bit better defined.

Yep yep. I stick to the continuous rating as well. Or, I would if I wasn't vaping at fairly low power anyway.

What got me intrigued about pulse rating was not to push limits. It was more this capacitor effect mentioned in the linked PDF. On tapatalk so won't quote. First I ever heard of it, at least. Will read more closely later on.

 

[Ayloxs]

Googling about the exact nature of what is meant when referencing pulse discharge doesn't uncover much that hasn't already been parroted on every vaping forum, but I did find these two articles that actually describe pulse discharge as more of a duty cycle type discharge, instead of the commonly thought short press of a button.

Yes, that is how my Googling went as well, and I had read the 1st link you posted. Your second link focuses on increasing the discharge rate of a battery through the use of pulse current (as opposed to continuous current).

Also, 'duty cycle' specifically describes "the percentage of one period during which a signal is active. A period is the time it takes for a signal to complete an on-and-off cycle." (quote from Wikipedia. I couldn't have said it better). That seems to confirm my logic that vaping cannot be described as using pulse current (however the devices mentioned by Dampmaskin in this thread seem to be an exception).

 

[Ayloxs]

A mod that uses 800 Hz PWM, draws pulses of up to 1.25 milliseconds. There are probably other mods with higher frequencies, and many with lower ones.

Can you give me an example of any mods like that? I've seen VV and VW mods, but never frequency-driven models. That sounds unnecessarily complicated, so I'm curious about what is being gained by using such sysetms.

 

[Ayloxs]

As I understand it (not an expert) vaping for most would probably come under pulse use BUT why take any risks and do you really want to cause yourself a serious injury just to get a bigger cloud? I don't approach these figures myself Vaping at about 4.5A now and that is about my highest.

My goal here is to better understand, not to test, the limits of my equipment. Looking for a good ratio of strong/safe.

My current setup, based on a full charge of 4.2V and a coil resistance of 0.29Ω, is delivering 60.8W at 14.48A. Tha's only half of the continuous rating of my VTC4's, and the full 4.2V charge certainly does not last very long

 

[Millah]

Can you give me an example of any mods like that? I've seen VV and VW mods, but never frequency-driven models. That sounds unnecessarily complicated, so I'm curious about what is being gained by using such sysetms.

Ummm.....practically every VW mod that came out of China a year ago was using PWM duty cycles. And they were absolute garbage. This was before YiHi started making the SX boards in response to the DNA. YiHi was supplying all the Chinese mods with these garbage boards that had a very low frequency duty cycle, which led to a lot of them making the "rattlesnake" sound for cartos. Nothing was being gained by doing this. I imagine they did it to make the boards cheaper, and because they frankly didn't give a rats ....

 

[Ayloxs]

Ummm.....practically every VW mod that came out of China a year ago was using PWM duty cycles. And they were absolute garbage. This was before YiHi started making the SX boards in response to the DNA. YiHi was supplying all the Chinese mods with these garbage boards that had a very low frequency duty cycle, which led to a lot of them making the "rattlesnake" sound for cartos. Nothing was being gained by doing this. I imagine they did it to make the boards cheaper, and because they frankly didn't give a rats ....

Interesting. That definitely changes the debate, as far as absolute limits, for that type of mod. I'd still be inclined to adhere to continuous discharge specs, as it's likely beyond the abilities of your average vaper to determine the duty cycle of their mod and translate that into actual power being consumed.

 

[Millah]

Well they all had a very low amp limitation on the board and went up to a max of 15 watts. This was before the DNA 20. So there was very little concern about amp ratings back then. The Joyetech Evic came bundled with a Samsung ICR battery with like a continuous rating of 5 amps or something. But when the DNA boards came out and used a DC signal, that pretty much retired the whole PWM shenanigans and now YiHi no longer produces boards like that. Now they just produce boards with excessive wattages .

You know what, actually I think the iStick was the first mod in a long time to bring back PWM. Which is odd. AND it uses a "mean" calculation rather than RMS. Ugh, thats a whole nother discussion. Devices that used to ship with an option for either Mean or RMS.