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mikepetro

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Reply with quote  #16 
My 2 cents, this is a 200w board, it is what you knowingly bought going in, If 200w isnt enough to drive your xyz coil then you have two choices 1)take a wee bit of mass out of your coil, 2) find another mod, perhaps a non-regulated 60C lipo mod.

I am not Evolv, however if it were my product, one which I built a ton of safety features in to protect folks against the bad stuff that can happens, I would not sacrifice my safety margin, or my builtin service factor just to satisfy the 1% of customers who want to push it beyond its intended safe design

I think the reality is that you could put out a 300w, or even a 500w mod, and there will be the adventurous few who will ask for 10% more power to push those mods even further.

Evolv has always placed safety #1 in their designs. I sincerely hope they never compromise that.
retird

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Reply with quote  #17 
Thank you Mike.....well placed and timely comments which I agree with 100% and yes "safety matters".... I'm not Evolv either nor one of the 1% that " wants more and more watts". 
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smartalec1020

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Reply with quote  #18 
I have a question for Evolv or anyone else if they know. Why limit the device to 200W? For some resistances, it can do more than 200W and some it can't even get close. Was the 200W just because it was a nice even number for marketing? Why not use 250W? It can do 250W in some cases. Did 250W seem like false advertising because it could only do that for a very small range of resistances? 200W is somewhat misleading because it can't do that for it's entire range of resistances. You could also just let the user set the device to any wattage (maybe only 999 to limit it to 3 decimals) because no matter what, it will only do the maximum it can provide given its voltage and current limits. If you put a 3ohm atty on there now and set it to 200W, it isn't going to do 200W.

I have no interest in using even close to that much power so I am not asking because I want it to change, just curious. Obviously there is a voltage and current limitation for the board. But the wattage limit is just what you can set the device to. Personally I think calling a device a 200W device or any other wattage is kind of weird. It would make more sense for this to be the DNA9V50A in my mind because it more accurately describes the board but that does sound as good lol.

Again, I am not asking for this to change (I would never use it). Just curious why. Wattage limits seem kinda arbitrary to me.
VapingBad

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Reply with quote  #19 
The resistance does not directly dictate the power rating, it is the max & min output voltage & current and resistance that do. 

You may know, but think watts on both sides of the board with a <=3% conversion loss, at 200 W output the board needs a fraction above 206 W from the battery, at min voltage (9 V) that is 22.89 A regardless of the output voltage, current or coil resistance.  The max output voltage is 9 V, current 50 A so both a 0.2 Ω & a 0.4 Ω resistance would still need 206 W from the battery at 200 W.

Ultra low res takes it over the output current limit (50 A)
A 0.05 Ω resistance at 200 W would need 63.25 A for 200 W which is over the current limit, but only need 3.16 V well within the voltage limit.

Higher res takes it over the output voltage limit (9 V)
A 0.5 Ω resistance would need 10 V for 200 W which is over the max voltage limit, but would only need 20 A well within the current limit.

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smartalec1020

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Reply with quote  #20 
Quote:
Originally Posted by VapingBad
The resistance does not directly dictate the power rating, it is the max & min output voltage & current and resistance that do. 

You may know, but think watts on both sides of the board with a <=3% conversion loss, at 200 W output the board needs a fraction above 206 W from the battery, at min voltage (9 V) that is 22.89 A regardless of the output voltage, current or coil resistance.  The max output voltage is 9 V, current 50 A so both a 0.2 Ω & a 0.4 Ω resistance would still need 206 W from the battery at 200 W.

Ultra low res takes it over the output current limit (50 A)
A 0.05 Ω resistance at 200 W would need 63.25 A for 200 W which is over the current limit, but only need 3.16 V well within the voltage limit.

Higher res takes it over the output voltage limit (9 V)
A 0.5 Ω resistance would need 10 V for 200 W which is over the max voltage limit, but would only need 20 A well within the current limit.


I'm assuming this is a response to what I said, sorry if it's not.

I was doing the calculations to get wattage from resistance given the specs of the board.

I agree with everything you are saying. And that's the point. All this math is needed. I'm an engineer, I don't dislike math. I just find it odd that we call a device a 200W device because the manufacture says you can set the wattage up that high. Think about it, the range that the DNA 200 can hit the 200W is actually pretty good. Let's say I made a device that could only hit 200W at one resistance (I'm to lazy to do the math right now but if you picked the right voltage and current limits you could do it). I could call this a 200W device. I wouldn't really be lieing would I? But it's not anywhere near as capable as the DNA 200. That's why I think defining boards based on the maximum wattage makes little sense.

I also don't see a reason to limit the maximum wattage you can set (other than marketing). If you set the device to a wattage it can't provide, it just does the highest it can. It already does that. So what's the point of a wattage limit?

Do you see how the wattage is pretty arbitrary?
smartalec1020

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Reply with quote  #21 
Quote:
Originally Posted by smartalec1020
I'm assuming this is a response to what I said, sorry if it's not. I was doing the calculations to get wattage from resistance given the specs of the board. I agree with everything you are saying. And that's the point. All this math is needed. I'm an engineer, I don't dislike math. I just find it odd that we call a device a 200W device because the manufacture says you can set the wattage up that high. Think about it, the range that the DNA 200 can hit the 200W is actually pretty good. Let's say I made a device that could only hit 200W at one resistance (I'm to lazy to do the math right now but if you picked the right voltage and current limits you could do it). I could call this a 200W device. I wouldn't really be lieing would I? But it's not anywhere near as capable as the DNA 200. That's why I think defining boards based on the maximum wattage makes little sense. I also don't see a reason to limit the maximum wattage you can set (other than marketing). If you set the device to a wattage it can't provide, it just does the highest it can. It already does that. So what's the point of a wattage limit? Do you see how the wattage is pretty arbitrary?


I was asking this questions because I was curious why 200W was chosen, it seemed arbitrary to me. But I just thought of something. I am no battery expert. Are there any negative effects of draining a battery very quickly? If there are then I could see the a potential reason to limit the wattage to lower than would the board is capable given the voltage and current limits. The higher the wattage, the faster the battery drain. So even though the board could handle it, you might not want to drain the battery that quickly. This was just a potential reason, like I said, not a battery expert.
VapingBad

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Reply with quote  #22 
Limiting the wattage is limiting the input side of the circuitry and not at all arbitrary IMO. In this case that is for safe and full use of a 3s Li battery, they allow down to 3.1 V per cell rather than your mod only performing as stated with a fresh battery.   The voltage limit is again from the battery and it being a step down converter.  The current limit is hardware, as this is what makes the internals get hot.
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MikeTheVapeDude

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Reply with quote  #23 
See, I find it insulting that this finally went in the direction I wanted it to after all my posts were deleted and I was made look like a fool who wanted to have a measuring contest with clouds because I vape on thick staple claptons on a daily basis. So now I just look like a cl0ud br0 and have no validity left in anything I said. If it's okay for people to quote electronics law at me that I've in the past on this forum clearly demonstrated I know due to being an engineer and treat me like an idiot and say I'm here to measure size, but it's not okay for me to call attention to how offensive that is to me I genuinely don't want to be a part of this community anymore. I'm out, all over this. This have given me a picture of what I need to know, and outside of getting firmware out of the thread I won't be coming back here or posting anymore. Thanks for insulting me and making me look like a fool.
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VapingBad

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Reply with quote  #24 
You had plenty of time to edit your posts.  I see nothing wrong with people quoting electronics law, this is the www and you cannot expect strangers to know your level of understanding.  All post are public, not a private message chain so we should be grateful when poster take the time to write an explanation that all can understand and it why this forum exists. 
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Latest versions of EScribe: DNA 200/250DNA 75
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