Introducing... my bottom feeding mod (MyMod)
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0.1V under load can often be the difference between a quality vape and an undesirable vape.
Not much to debate either the batt holds its voltage under load or it doesn't.
.00018 doesn't look significantly different than .00020 until a load is applied and it translates to 3.8V vs. 3.7V during use.
Tapatyped
Given how the internal resistance changes with charge level and age, I just don't see it being as big a deal.
Granted I haven't done any loaded voltage measurements on 18650 cells, and if I had it wouldn't have been with 20A loads.
I'd love to look at any published data.
I haven't had any luck finding internal resistance numbers.
I'm guessing the actual voltage difference are a factor of 10 less (0.01V)
PM me. Probably not the best place to discuss.
That's what he includes. But it's a standard automotive fuse (ATC/ATO size I think) so could be changed.
Maybe I missed this but what was the reason for going with a 10A fuse VS a 15 or better yet a 20?
It does seem kind of overkill. I'll change mine out to a 15 or 20 amp as soon as I get it. I mostly vape at the .25-.3 ohm range, pushing 15-17A, so a 15 would work for me. If not, I'll boost it up a bit more. I've been vaping mechanicals for a long time and have never had any kind of fuse. I guess the closest thing would be on my Reos with the spring that would drop in case of a short, but I never had that happen.
Because 10A covers the majority of users.
Remember, a fuse doesn't blow instantly at 101%.
Most can run for minutes at 135%, even several seconds at 150%
If you look at the specs you'll see a window, max and min time to blow. While there's some variability, it does average more to the max.
^^what he said, kinda...
In previous testing a while back in the Reo threads, it was found that anything over a 10amp fuse wouldn't blow quick enough. It exposed the battery to the danger of getting to the point of venting before the fuse blew...
In previous testing a while back in the Reo threads, it was found that anything over a 10amp fuse wouldn't blow quick enough. It exposed the battery to the danger of getting to the point of venting before the fuse blew...
This^
A 12.5A fuse would likely suffice for a 0.2 ohm build. Though would likely heat up and increase resistance robbing the coil of voltage.
That's why I commonly used a 15 amp fuse in my grands when I had my fuse mods installed.
That brought me to the revelation that I had nearly no protection already and was likely to lose a battery before the protection did it's job.
So I eventually went full mechanical on my grands.
Tapatyped
Got a link to those threads?
As I said, look at the data sheet specs. Here's Bussmann's sheet for ATC "fast acting" fuses.
http://www.cooperindustries.com/con.../product-datasheets-b/bus-ele-ds-2009-atc.pdf
The important bit is from page 2.
% of fuse Operating time (sec)
amp rating Min Max
110 100 Hrs —
135 0.75 120
160 0.25 50
200 0.15 5
350 0.04 0.5
600 0.02 0.1
So, at 135% (13.5A for a 10A fuse) it could blow as fast as 3/4 of a second (but no faster) and take as long as 2 minutes
And 160% can go for nearly a minute.
Since most vape with 5-10 second hits, running at 160% of rated current should be no problem. The fuse may eventually blow after many cycles and you might get a quick fuse occasionally but most won't blow for a long time.
20A batteries can handle 40A for 5 seconds, or 32A for 50 seconds, and even 27A for 2 minutes, so a 20A fuse would protect it under a continuous fire condition.
Were you looking for protection against short or constant firing?
A short is going to spike the current over that 600% (depending on the internal resistance of the battery and the location of the short) and blow the fuse "instantly."
Constant firing on a 0.2 Ohm coil is ~20A and in the continuous range of common batteries used. At 133% of the 15A fuse rating, it would take 1-2 minutes for it to blow.
Now if you only had a 10A rated battery, is see some concern, but you probably shouldn't be running a 20A load on a 10A battery, even pulsed. Still, I doubt 200% rated load for 2 minutes would cause it to vent.
No, better performance.
1 to 2 minutes didn't happen. The voltage sags too much and the 15 amp automotive fuse simply doesn't blow.
With a dead short on a new vtc4, it takes a good 3 to 5 seconds or more for the 15 amp fuse to blow... if it does at all.
Calculations of firm numbers aren't what happens in actual use.
This is not conjecture.
This is what happened with somewhere around a dozen fuses when tested.
Though, with that build, a 10 amp fuse would blow anywhere from instantly to within a couple days use.
Tapatyped
How would a fuse improve performance?
A fuse's only role is some sort of protection.
I can see that. So with the voltage sag the current dropped to low.
That's surprising. You'd think it'd spick the current high enough and long enough to blow the fuse.
Wish I still had access to the equipment I had at my old job.
But it appears automotive fuses are NOT a good fit.
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The spring was such a poor performer that nearly anything would be an improvement.
For me, the FUSE was just a means to an end to bridge the gap and take up space so the battery could make connection at both ends.
A tried and true method learned from the thread linked above.
I've since moved on.
My grands now are and hit like high quality mech mods.
Even if a nut and bolt as a negative contact look a little ghetto. But you don't see that with the door on.
Tapatyped
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That video in the first post shows a lot lower voltage under load than I would have expected.
Reading a bit more I now see the answer to my question to beck.
Didn't realize the resistance in the mod was so high. Lots of wasted power in the stock configuration.
I hope this mod does better in that regard.
I've been waiting on the magnets. I should get them shortly.
I wonder what is the typical wattage that bottom feeder folks vape at?
I wonder what is the typical wattage that bottom feeder folks vape at?
Yep. From the mildest of tootlepuffers to the craziest of cloud chasers.
Depending on atomizer and mood between 7.5 and 30ish usually.
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