there would be 2 taps, one top and one bottom. and the plates would act as space filler and conductor for the "-" of the battery. I figure if the plates were 2mm thick it would work out about perfect. The solid rectangle would work if it were made of plastic, and that is exactly what i was looking for but it needs to have contacts on the top for the battery and bottom for the mod and be 6 to 7 mm tall and 15mm deep... that is kind of like finding a unicorn, lol. I figured just soldering on some 2mmthick plates to the taps would be easy enough.
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Its hard to tell from my pic, but the taps would be modified by cutting off the end that your saposed to plug into. and the shrink wrap isnt for electrical safety as much as it would be to maintain form. Back when I smoked I used to make a "Lighter leash" by shrink wrapping the bottom of the lighter making it snug enough to stay in while still allowing me to pull it out.
so the 7.5 & 10 amp would blow in <5sec @ 15 & 20A, right? Cold resistance looks like .010Ω, right? (learning curve)
Yes, well, I have a shop, and some scraps around, Richlite would work well. Here's what I was thinking. Bad drawing, sorry; but if it's what you were thinking . . .. bad drawing good enough.
Orientation is arbitrary. Maybe rotate right, 90 deg.
Orientation is arbitrary. Maybe rotate right, 90 deg.
Are these fuses specialty? Smaller than what I can get at the auto parts store?
10A fuse would have .0074ohm resistance and typical voltage drop would be .108V. Not the greatest but I'm sure there may be better fuses out there, I haven't looked very hard. As far as opening time, I look more at the .1sec which would blow at 600% (60A). Our batteries can handle that burst, because they are typically rated 20A continuous and 60A peak, or in the case of the sonys 30A contin 90A peak.
oooooooooh, the 15A fuse is only 0.00458Ω cold! With a battery shorted, I'm sure we'd see enough amperage to blow it in under a second . . . . . wouldn't we? (←totally don't know)
Yeah, just read your post, above mine.
Yeah, just read your post, above mine.
These fuses can be found at most gas stations, hardware stores etc.
That design would absolutely work! Just make sure you account for the 19mm depth and the alignment of the + dowell with the battery.
I wish I had a shop, but all i have is bunches of solder/shrink wrap and visegrips
That design would absolutely work! Just make sure you account for the 19mm depth and the alignment of the + dowell with the battery.
I wish I had a shop, but all i have is bunches of solder/shrink wrap and visegrips
Yes the current will jump up to as much as the battery can put out. ~100A - 150A. The protection should trip be fore the battery hits its instantaneous peak current value (60A). I would think that the 15 may be too high, and could melt the button (unless its teflon). The fueses are so cheap i would start with a 7.5 and see how that works, then work your way up.
Well, SeaNap, that's another really cool part of your idea. Once an individual is rigged up to accept these fuses, it is their choice whether to pop in a 5Amp or a 15.
These fuses can be found at most gas stations, hardware stores etc.
That design would absolutely work! Just make sure you account for the 19mm depth and the alignment of the + dowell with the battery.
I wish I had a shop, but all i have is bunches of solder/shrink wrap and visegrips
throw in a roll of duct tape, and you can call it a shop
6.6mm or ~.260" (that is to the shrink wrap that wraps under the batt's bottom edge)
Yup, I get .258" & .249" on my Grands. My Mini 2.1 is .327". And for the heck of it, .256" on my VVG. All using AW IMRs (18650s are 1600s).
The blade fuses are good, but they will be quite slow to blow at only 4V and their rated amperages - the button will melt before them, depending on the fault current (how "bad" the short is and how good the battery).
Please try this on an actual mod before doing any serious modding work.
The onetime fuses that are most suited to our needs, I believe, are these: http://www.farnell.com/datasheets/575727.pdf @around 5-10 Amps, very fast blowing.
In other news: I am still waiting for the teflon buttons. My PTC (7A in place of the spring, with the Bierdeckel-MacGyversim) is holding up fine. I use it all day long for days.
Please try this on an actual mod before doing any serious modding work.
The onetime fuses that are most suited to our needs, I believe, are these: http://www.farnell.com/datasheets/575727.pdf @around 5-10 Amps, very fast blowing.
In other news: I am still waiting for the teflon buttons. My PTC (7A in place of the spring, with the Bierdeckel-MacGyversim) is holding up fine. I use it all day long for days.
Chris, take a look at the data sheet for that RGEF1000. It has a (relatively) terrible responce time (see img below), its resistance is 70mOhm (by comparison the blade fuse is 7mOhm), and the way it's mounted in your picture the legs of the PTC will increase the resistance of the PTC; It's all about surface area. PTC's can still blow, they don't last forever. The reason I am going with a one time fuse is because generally their electrical characteristics will more suitable to our needs of low resistance at 10A and quick blow before reaching 60A, and I'm focusing on the blade fuse in particular because of their abundance, we can pick up a pack of them for 3 bucks at any gas station. The car fuses are 12V fuses, which is perfect for our operation. Voltage doesnt matter in regards to the responce time of the fuse. Voltage ratings of fuses are there to protect the insulation. I regularly uses 250V fusing on 120V control, and yes this is code (UL508A). The fuse will blow from current, that is all its looking at NOT watts or volts.
Those farnell fuses do have better characteristics than the blade fuses, but not by much. I have found similar fusing on Littlefuse' site and have ordered some. The problem is mounting them to the mod. Did you have an idea on how you would mount that fuse/holder?
PTC
Blade Fuse
Those farnell fuses do have better characteristics than the blade fuses, but not by much. I have found similar fusing on Littlefuse' site and have ordered some. The problem is mounting them to the mod. Did you have an idea on how you would mount that fuse/holder?
PTC
Blade Fuse
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They do make slo-blow blade fuses, but we are not looking at those. The standard car fuse is fast blow, and fast acting. You said the button will melt before they pop, have you done testing with the blade fuses? How long of a duration of a short have you noticed until the button melts? It would be interesting to experiment and find out at what temperature and at what current the button melts.
From comparing the data sheets it is easy to see why the PTC didnt open quick enough, .3sec @ 100A, as compared to the blade fuse .01sec @ 100A.
From comparing the data sheets it is easy to see why the PTC didnt open quick enough, .3sec @ 100A, as compared to the blade fuse .01sec @ 100A.
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(where does the animosity come from? ... read data sheets? yes, I did, spoke to a manufacturer about it and posted the results) Let's drop this and work together on the problem, shall we?
I can tell the button starts melting before my 7A PTC (or the spring, for that matter) trips (or collapses). I have a pair of buttons with melted contact areas, because of my tests. Depending on the wear and shape of the tip of the firing pin, the type of the short and the amount of Noalox, it gets hot or very hot, but usually hot enough. Those original firing buttons are made of some wimpy stuff =)
Yes, of course a fast blowing one time fuse is faster than a PTC.
I don't want to belittle the idea of using a car fuse - it's a good idea although they are a bit too big for mods in my opinion. I just wanted to hint that actual testing in a mod is good before manufacturing anything above the quality of a jury rig, to avoid frustration.
The one time SMD fuses I posted actually work at our voltages (and quickly) and I know that because I use the type in my GGTS for safety in an electronic switch (but I only used 4A in there so far) . But that mod doesn't have the tiny firing pin point our REOS have, it actually uses a micro switch in this configuration, so I don't have that button heat problem there.
Here's the part in use:
The Teflon buttons arrived:
(white ones are PTFE (Teflon), red one is for fun =) )
I'll report back tomorrow.
I can tell the button starts melting before my 7A PTC (or the spring, for that matter) trips (or collapses). I have a pair of buttons with melted contact areas, because of my tests. Depending on the wear and shape of the tip of the firing pin, the type of the short and the amount of Noalox, it gets hot or very hot, but usually hot enough. Those original firing buttons are made of some wimpy stuff =)
Yes, of course a fast blowing one time fuse is faster than a PTC.
I don't want to belittle the idea of using a car fuse - it's a good idea although they are a bit too big for mods in my opinion. I just wanted to hint that actual testing in a mod is good before manufacturing anything above the quality of a jury rig, to avoid frustration.
The one time SMD fuses I posted actually work at our voltages (and quickly) and I know that because I use the type in my GGTS for safety in an electronic switch (but I only used 4A in there so far) . But that mod doesn't have the tiny firing pin point our REOS have, it actually uses a micro switch in this configuration, so I don't have that button heat problem there.
Here's the part in use:
The Teflon buttons arrived:
(white ones are PTFE (Teflon), red one is for fun =) )
I'll report back tomorrow.
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