A pdib mod :>p

[ChrisEU]

Absolutely!

This 20Amp fuse thing needs pursuing!

If anyone finds a vendor for single item purchase on these, please let us know. Also, If anyone has one, I would gladly pay you for it: with one in hand, I could fabricate a housing for the REO where the spring usually sits.

Go to Newark | US - Electronic Components Distributor | Electronic Parts Distributor and search for "RGEF1000" Minimum quantity is 5 pcs, but they are only 38 cents each. But before you do that, let me wait for mine to arrive (perhaps on monday) and see if they are quick enough.

My idea is to use the PTC in parallel to the spring, in place of your shim. The spring is then only used for its structural role until the PTC triggers. If the PTC triggers and closes, the current will heat up the spring and collapse that, too. So we would have the safety of the hot spring, but not the resistance.

 

[SeaNap]

So we would have the safety of the hot spring, but not the resistance.

Not necessarily, when the spring collapses it's goal is to drop the battery down away from the positive terminal (firing button). With the fuse underneath the battery there would be no where for the battery to drop to. So it would be an unnecessary (ineffective) redundancy.

When I design control panels I always put the safety contact on the positive side of the coil. Now even though the hotspring looks like its installed on the negative side of the battery, when tripped it actually opens the circuit on the positive side. The fuse on the bottom of the battery will open up the circuit on the negative end. Will this still mitigate a short circuit by removing power; Absolutely! However, the reason this is not standard practice is because if you were to be "grounded" (in this case, touching any part where the neg is connected, such as the metal fuse holder on the bottom of the batt) there is a possibility that you can "complete the circuit" with your fingers.

In the design thats floating around in my head, this would be a very unlikely scenario, but I'm just letting you guys know of the possibility, and why generally when you kill power you kill it from the positive side.

That being said, when you have been shocked by 480V, 230V, and 120V as many times as me I doubt you would even feel 4V.

 

[SeaNap]

I apologize Chris, I didnt look at that particular fuse before posting. In your design when the spring collapses the battery will drop. I still don't think that this redundancy would be very beneficial. Don't get me wrong I design redundant systems all the time, but in this case I think that you would just burn through springs after the safety has already worked. There is something to your design, and I would like to come up with something that would be more of a failsafe to catch a short circuit IF the fuse did not work. But if the fuse works and opens the circuit, there is no need to put power back into the system for the spring to collapse. That would act like a double short, and be hard on the battery.

Great ideas though! Keep us up to date with mounting ideas.

 

[ChrisEU]

Not necessarily, when the spring collapses it's goal is to drop the battery down away from the positive terminal (firing button). With the fuse underneath the battery there would be no where for the battery to drop to. So it would be an unnecessary (ineffective) redundancy.

Yes, I understand that - that's why I don't want a fuse (PTC) in series with the spring, but in parallel. It is not under the battery, but beside it, just like the shim that's in the first post:

Edit: We need the (or at least some) springyness in the system for it's well, springy attributes. Something has to push the battery up. I agree that my way is redundant and would ruin a perfectly fine spring, but the goal is to remove the resistance, not to replace the spring.

 

[ChrisEU]

Wups, just noticed newark is selling these with a MOQ of 5000 - my apologies, Farnell in Germany starts at 5 =) So, pdibby, that is not the place for you to order singles =)

 

[ChrisEU]

This would save the spring in case of a short - but it would need modding of the REO, at least a piece of insulator:

With constructions like this it would be far better to put the PTC somewhere in the positive path, though, in true series. But it should work well.

 

[SeaNap]

Series or parallel doesnt make a difference in your first design. Our goal is to reduce the resistance in the mod, so in theory by putting that fuse in place we are assuming that the fuse has less resistance than the spring. Under that assumption, electricity will take the path of least resistance (the fuse) so under normal opperation, ALL of the power will be going through the fuse and nothing will be going through the spring. So if there is a short, the fuse will do its job and open. Now ALL of the power will be diverted through the spring, which will in-turn heat up and collapse.

Also, inorder to decrease the resistance, the larger the surface area the better. Think water through a hose. The resistor that you've got has very tiny legs (smaller the connector larger the resistance) The way those are suposed to be mounted is soldered to the copper in a PCB w/ 90% of those legs cut off. With the way you have it in the diagram, the fuse would probably be better than the spring, but there would be room for improvment.

I don't mean to discourage you at all. You've got some great ideas.

My idea is to have a metal base, layer of plastic (stablizer), and metal plate touching battery. excuse my crude paint skills:

 

[SeaNap]

Ok i see what your doing with the isolator.

dhomes didn't seem to have a problem getting his battery to stay with-out a spring. Homes, is the battery held in by tension? Do you need to back the screw out to get the battery out?

 

[ChrisEU]

Heh, your paint-fu is better than my paint-fu!

Well, our designs are pretty similar now.

The resistance of the legs of the PTC can be ignored, thin or not. The manufacturers rate the devices at 50A or 100A max @ 16V and have design values of max 0.08 ohms. If we get 0.1 ohm, that's fine with me. But, as said before, let's see if it works in practise.

 

[dhomes]

Yo! vape mail in!

So I got this now, if this works at 15 watts on a 1.5 ohm microcoil as i'm expecting then I'll soon be the owner of a VV Reo Grand body (for kick 2 + 18650)

With a .7 ohm coil though, I prefer the mechanical

But this should give me 4.75 Volts on a 1.5 ohm (which I ussually use in the provari) and still give me the security features

 

[pdib]

Heh, your paint-fu is better than my paint-fu!

Well, our designs are pretty similar now.

The resistance of the legs of the PTC can be ignored, thin or not. The manufacturers rate the devices at 50A or 100A max @ 16V and have design values of max 0.08 ohms. If we get 0.1 ohm, that's fine with me. But, as said before, let's see if it works in practise.

When I measure the resistance of the current spring, am I not getting about 0.1Ω?

 

[dhomes]

When I measure the resistance of the current spring, am I not getting about 0.1Ω?

Pdlib, resistance on the spring maybe low, resistance the contact assembly you have will vary with the voltage, hence it's hard to measure with a multimeter

 

[dhomes]

Ok, 1.6 ohm with kick 2. It aint't the same!

You know you spoiled yourself when 15 watts doesn't cut it anymore!

 

[pdib]

I was wondering how satisfying that was gonna be.

 

[pdib]

Right, so the resistance of the spring increases with current (heat). That's what I figured, since the lower res. coils increase v-drop. Also, that's why my v-drop is constant. I've circumvented the spring's "resistance wire".

 

[dhomes]

I was wondering how satisfying that was gonna be.

I just made the coil so it hasn't fully broken in

Compared to a provari, not bad at all!

But after hitting this puppy at 30 watts....well, not the same ballpark

Can't understand how some people say that 8, 9 or 12 watts is a sweet spot

 

[dhomes]

Ooooihhhhh! I was in such a hurry of tasting the kick 2 that I didn't torch the coil, maybe the slight flavor off is coming from there!

Off to recoiling!

 

[pdib]

The wheels are coming off the bus . . . . . but he still has hope.

 

[pdib]

What about a capacitor? Can a capacitor give a 10 sec burst? At, say, 10A? Can we fill a capacitor with juice from our battery, and have the capacitor shoot the coil?

 

[dhomes]

I was wondering how satisfying that was gonna be.

Correction! I just redid a 12 wrap microcoil (1/16 drill bit) with kanthal 28, this time torching it real good, it's working FANTASTIC

my previous, off taste one was a 15 wrap mini coil (5/64") with kanthal 27, that wasn't impressive at all, but this!!!!!

Sold on the second REO, VV Grand body for 18650 + kick 2