SPRING? . . . . .. what spring?

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pdib

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I was thinkin' I'd read that BeCu had better conductivity than brass but my search-fu is netting me different results. I think I haz it backwardz. :D





edit: Apparently, it depends on the particular BeCu alloy. Some have better conductivity, some worse.


Copper and Beryllium Copper undoubtedly have better conductivity than brass. But we aren't conducting that much stuff. I'm sure there's a difference; but not a perceptible one. It's splitting hairs. (at least based on any measurements and configurations I've done).
 

EagleTa2

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I think I need some bumble bee type assistance...

I made up a fuse block out of .253 delrin...turned out to be way too thick and couldn't fit battery in... I sanded for what felt like forever...and got it down to .210

I grabbed a fresh AW18650 2000 mah battery. Fresh off the charger at 4.24 v.

With stock spring and the coil that is currently installed (say .85 ohm) voltage at the posts was 3.58
With fuse holder and mini 10 amp fuse installed, and same coil voltage at the posts was 3.78.

So, this would tell me my fuse mod saved exactly .2 v of voltage loss. Hmph....I thought it would be more.

Dibby...I will say that your screws are much prettier than mine. I'm using 8-32 brass threaded rod and cutting a nice slot in there is a beeotch with a dremel when the guy holding the dremel has tremors!

Would I get less voltage drop with a 1600 battery I wonder? I should go measure that.

Any ideas?

Thanks
Geo
 

pdib

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Hey, Geo. Couple things. Your V-drop savings are going to be proportionate to your resistance. If I'm gaining .4V at ~.45Ω, you'll never see that kind of difference at .85Ω. You're probably in the ballpark for what you can get. The other is, yes, the AW 1600 has way lower internal resistance than does the 2000. You will gain something there, for sure. As far as "how much", that too is dependent on your coil's resistance. I definitely notice it at my preferred res., can't say for sure that you will. I would guess that, if you were vaping at 1.2Ω, you pretty much wouldn't notice the difference in batteries aside from the sag the 2000 can have at around 3.9V charge.



ADDIT: My birthday starts in 16 minutes . . .. . yippee.
 
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custom-classic

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i think i need some bumble bee type assistance...

I made up a fuse block out of .253 delrin...turned out to be way too thick and couldn't fit battery in... I sanded for what felt like forever...and got it down to .210

i grabbed a fresh aw18650 2000 mah battery. Fresh off the charger at 4.24 v.

With stock spring and the coil that is currently installed (say .85 ohm) voltage at the posts was 3.58
with fuse holder and mini 10 amp fuse installed, and same coil voltage at the posts was 3.78.

So, this would tell me my fuse mod saved exactly .2 v of voltage loss. Hmph....i thought it would be more.

Dibby...i will say that your screws are much prettier than mine. I'm using 8-32 brass threaded rod and cutting a nice slot in there is a beeotch with a dremel when the guy holding the dremel has tremors!

Would i get less voltage drop with a 1600 battery i wonder? I should go measure that.

Any ideas?

Thanks
geo

Pics, man!!! :D
 

Alexander Mundy

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I think I need some bumble bee type assistance...

I made up a fuse block out of .253 delrin...turned out to be way too thick and couldn't fit battery in... I sanded for what felt like forever...and got it down to .210

I grabbed a fresh AW18650 2000 mah battery. Fresh off the charger at 4.24 v.

With stock spring and the coil that is currently installed (say .85 ohm) voltage at the posts was 3.58
With fuse holder and mini 10 amp fuse installed, and same coil voltage at the posts was 3.78.

So, this would tell me my fuse mod saved exactly .2 v of voltage loss. Hmph....I thought it would be more.

Dibby...I will say that your screws are much prettier than mine. I'm using 8-32 brass threaded rod and cutting a nice slot in there is a beeotch with a dremel when the guy holding the dremel has tremors!

Would I get less voltage drop with a 1600 battery I wonder? I should go measure that.

Any ideas?

Thanks
Geo

That is better than you are aware of.
Doing some quick math reveals the following:
You were at 12.82 watts at the coil with a .85 ohm coil using 17.85 watts from the battery.
Given about 50mohm internal resistance for that battery you should be able to up the resistance to about 1.2 ohms now and be at the same wattage at the coil.
Your current will drop from 4.21A down to 3.26A and you will be saving right at 4 watts from your battery which will get about 20% longer vape time.
If you decide to do so, you should change the coil resistance via wire gauge (or better yet wire resistivity if possible) and minimize the change in number of wraps or inside coil diameter.
Some compensation by increasing the wraps may be necessary due to a smaller gauge so you keep the same surface area.
The more you mess with the number of wraps, inside coil diameter, and wire gauge (in that order) the more you mess with the power to surface area factor.
Mess the power to surface area up too much and you have to change the wattage via resistance which changes it again and it becomes a vicious cycle to get the same vape qualities.

Handy chart

KanthalGauge_zpsea58b187.jpg


If I ever get the spare time (like that's going to happen) I will make an excel calculator for this type of stuff.

:vapor:
 

EagleTa2

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Happy happy Birthday Mr. Bee! My father in law's bday was yesterday and my father's bday is tomorrow....you're in good company my friend... I hope you have a wonderful day!

Mr. Mundy.. Thanks for showing me the light..I see it now. I don't necessarily mind that I have increased my operating wattage by reducing my v drop. I am very happy to hear of longer battery life. With your vicious circle analogy, I now have a new question.

Let's suppose that I changed my coil so that I was matching my original power (watts). Would my power savings then increase to 40% longer battery life while producing the same vaping experience I was at before? Or in your calculation, was that the 20% increase?

I may have to make a new one of these...as this one makes the battery very difficult to put in and remove. Pictures soon

Thanks,
Geo
 
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Alexander Mundy

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Happy happy Birthday Mr. Bee! My father in law's bday was yesterday and my father's bday is tomorrow....you're in good company my friend... I hope you have a wonderful day!

Mr. Mundy.. Thanks for showing me the light..I see it now. I don't necessarily mind that I have increased my operating wattage by reducing my v drop. I am very happy to hear of longer battery life. With your vicious circle analogy, I now have a new question.

Let's suppose that I changed my coil so that I was matching my original power (watts). Would my power savings then increase to 40% longer battery life while producing the same vaping experience I was at before? Or in your calculation, was that the 20% increase?

I may have to make a new one of these...as this one makes the battery very difficult to put in and remove. Pictures soon

Thanks,
Geo

The 20% was based on changing the coil resistance to about 1.2 ohms.
But wait, it should actually be more than that if you changed the coil to 1.2 ohms.
I would have to know the battery voltage when you change batteries and the discharge curve of the battery at your load to figure that and that's not happening so math fails me as to how much.

With your existing coil you have increased your amperage by about 5.5% so your battery will deplete at a faster rate.
However your getting about 31% more power to the coil so you can vape to a lower battery voltage.
That is assuming you change the battery when the vape depletes to the same level as when you changed the battery before.
That is what I didn't take that into consideration before.

Screw math and give feedback as to how much juice you use before you change batteries as compared to before.

In real life with similar coil resistance to yours, AW1600mah batteries, brass firing pin, and 10A fuse I am vaping about 1/3 more juice before I change batteries now.

Got to stop thinking now, as sometimes I think myself into a vicious cycle.
 

pdib

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EagleTa2

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There's a perfect size somewhere in that block, Geo. What I did at that stage was to take it out, give it 5 swipes with a very fine file, and check for fit (repeat as necessary); until it was the perfect fit.

Thanks dibby. My concern is the brass screws... Obvious concern is that if the were flush to the face of the block they would not make contact and thus...no workie.

Please share how much your screws protrude from your block? I plan on my next block being about .190 thick....

BTW, I'm the only woodworker I know that uses a dial calipers instead of a tape measure. I'm a bit ocd that way, I s'pose.

Thanks
Geo
 
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