The Magic-Flight Box

[TommyDee]

I am saying that these elements add resistance. Basically, if you push a box mod hard to the rails, it can see a 0.056 ohm resistance. If I add wire, that 0.056 ohms becomes something greater reducing the current requirement. In your take you are not adding the additional impedances from wire and connections. With the added resistance, we're talking closer to 0.1 ohm as a circuit resistivity. Now we are at the more reasonable current levels. And no, I am not stressing the cells in the least. Imaging what those AA Ni-Cd's were seeing!

I measured the input current from the wall wart to the PA. Although the wall wart rating on the label is 1 amp, it puts out 2. Later versions are also marked 2 amps. I know this because that is what the PA draws at full power. So what I was saying is that if I only have 24 watts going into the PA, I can't have more than that going out. The cells are not more powerful than the any of the power adapters available for the LB. So again, I am not worried about these cells. And even at that, say 20 amps, I'm still covered with the 3800mah cell. Their 5000 mah cell is rated to 42 freakin' amps! Good luck finding that in a Li-Ion.

Oh, have you read the part about my RC racing past? I do know about Ni-Cd's

 

[scy123]

Wal-warts are flaky. I had broke one awhile back and had to find a v12 replacement. I found ones marked at 12v and tested 18v even.

BTW:
1.2v @ 42a = 55w.
3.6v(nominal for li ion) @ 30a(the limit for the li ion I have) = 108w.

I can put out 55w more with a li ion then a Ni-Cd. I don't even know if 42a Ni-Cd exist seems like not.

I know about R/C cars. I used to buy all Unlimited Engineering Supermaxx. they where all 7075 billet aluminum. I switched from Ni-Cd to lipo decades ago cause lipos had way more capacity and current.

Now li-ion has more capacity and safer.... lipo still holds current crown.

BTW a 3800mah cell with 5c rating would be 19a limit.

Edit: also I think you are confusing NiHM with NiCd. NiCd is acually really not good and the highest rated sub-c I found was 3500mah and 17.5a. NiHM is a step up 5000mah and 30a was highest I found.

 

[TommyDee]

Not according to Tenergy. They claim a 38 amp peek. And again, not hitting 19 amps but I'd feel safe at draining a fresh cell at 20 amps.
https://power.tenergy.com/tenergy-p...flat-top-rechargeable-batteries-special-size/

10th scale offroad here. Fried a lot of cells but never blew one up.

I don't know that I want to pull 30 amps from an 18650 but but good to know the limit. In this case, true, better energy density but capacity to deliver high current is not the norm. Capacity suffers significantly when you push higher currents. Enter IMR or wherever the tech is now. The other problem of course is converting 3.6V to around 1V. That too adds significant inefficiencies at this load. So I would never argue over battery chemistry, there are some fundamentals in this realm that keep things from being simple.

And therefore I will leave it at simplicity wins out over tech on my side (cell solution) but I am wholly jealous of those that can design and define a box mod solution that will essentially just 'work' on the LB. Not the MD, but the LB. It wasn't a simple feat until I folded on accepting the use of the larger cells. Then it became dirt simple. When I over-engineered it, I screwed it up. Added the charge capability in the stock charger and my LB world is whole. When the 5000mah cells drop to a reasonable price, I'll rebuild the wands for those instead. But I do what to see what you come up with for a box mod solution for the higher current.

 

[scy123]

That is a NiHM not NiCd and burst and continuous discharge is not the same. A lot of battery mfg like to trick you and try to claim burst like it was continuous. Notice they say "up to"?

Their 5000 mah cell is rated to 42 freakin' amps! Good luck finding that in a Li-Ion.

1.2v @ 42a = 55w.
3.6v(nominal for li ion) @ 30a(the limit for the li ion I have) = 108w.

I don't know that I want to pull 30 amps from an 18650 but but good to know the limit.

Dude...

 

[Tranquility]

BTW:
1.2v @ 42a = 55w.

You two have obviously played a LOT more around electric things than I, but, why 55W?

 

[scy123]

Ohms law. Thats how much the battery can pull before reaching limit.

For nihm rated 42a
https://www.calculator.net/ohms-law...t=ampere&r=&runit=ohm&p=&punit=watt&x=66&y=13 (this one i made a mistake and enter 1.3v instead of 1.2)

For 18650 rated 30a
https://www.calculator.net/ohms-law...nit=ampere&r=&runit=ohm&p=&punit=watt&x=0&y=0

 

[Tranquility]

(this one i made a mistake and enter 1.3v instead of 1.2)

I didn't question the li ion calc. But, with all the numbers starting to fly around, I just wanted to make sure I didn't miss something.

 

[scy123]

I didn't question the li ion calc. But, with all the numbers starting to fly around, I just wanted to make sure I didn't miss something.

I know, I have to use online calculators for everything. Better for me though.... as long as don't get a bad calculator somehow.

The numbers are extremely important though. I would not even make this if I figure I could not make it safe enough.

Edit: likely screen will blow and that is worst that can happen I imagine. Might be able to put fuse that will blow before screen does, haven't ran any test.

Edit: Would be obvious something is wrong.... like your herb being burnt long before anything bad should happen.

Edit: Oh I just seen the Mod Dock. Search for it on Reddit. That is kinda basically what I would be making. Mines would be a lot nicer though.

 

[TommyDee]

Hahaha!!! Yep... and I wasn't worried about screen blowing. Cells are voltage limited so no chance of a current-runaway. Besides, cells that are stressed get hotter than hell. These barely blush on a hard roasting. It's in the palm of my hand. Trust me, I've given this a run for its money. I am more than satisfied. Bottom line, if we're getting 20W from a single Ni-Mh to the screen we'd be doing damn good. I'd say 15-18W depending on where you are on the usable level of the discharge curve.

I'm aware of nominal (5C) and their 'peek rate' discharge advertising. Still, 42 amps on a motor startup is impressive when you can maintain 25 amps continuous after spin-up. Anyway, numbers are great but I took those numbers to task. Glad I did.

@OldNewbie - @scy123 is very correct in how useful a box mod adapter could be. I'm still on the fence on the usability of the interface since it will require certain features in a box mod. And I don't have any of those or even know how to make sure any candidate unit does. Box Mods can raise havoc if you overpower the screen. As for 1.2V Ni-Mh cells... no... these cannot blow a screen. That is the voltage the box was designed for.

Oh crap, @scy123 - I have a really cool 510 mod that can only do 0.2 ohm or greater and it times out too soon. It's a COV Mini Volt which is a perfect shape for this. 40W and 18500 Li-Ion (internal). Do you think you can repurpose something like that for -on- watts mode to work with the 0.05 ohm? That last part may require a hardware change. It works great on Muad Dib but unruly to handle. Your concept should solve a lot of that with the exception of holding that fire button.

 

[scy123]

I have a really cool 510 mod that can only do 0.2 ohm or greater and it times out too soon. It's a COV Mini Volt which is a perfect shape for this. 40W and 18500 Li-Ion (internal). Do you think you can repurpose something like that for -on- watts mode to work with the 0.05 ohm? That last part may require a hardware change. It works great on Muad Dib but unruly to handle. Your concept should solve a lot of that with the exception of holding that fire button.

Only certain mods you can flash firmware easily. And changing it to accept lower resistance is not a good idea.

 

[TommyDee]

I doubt VOC is one of them. Okay, so what 510 mod would do what we need in a small package?

The Volt Mini will do Muad Dib with your 510 adapter. A simple 3D printed girdle can slide to lock the fire button. Timeout is way after a lot of concentrate is vaped so that may be okay. So yes, for your setup, this is great! I prefer herb.

@Anyone - help me here; Box mod 510 with lock-on capability, small form-factor, 20-30W range, and 0.05 ohm capable. What's out there?

Quick note on the screen. I got new Muad Dib screens. Wanted to see what they could do. I got it visibly glowing blood red with any of my MF cells. Don't do this on new empty screens though. It anneals them.

 

[scy123]

Smallest mod I have is the Target Mini. https://i.imgur.com/5ndQe7m.jpg

Mod Dock guy reports 0.14ohm on regular mflb at connections. That will be close to what my adapter will be. The Target Mini has a ohm limit of .1ohm(meaning it will only fire over .1ohm). I checked manually. It will fire up to 40w also and is the lower of feature mods. Also most will probably want to use it with temp control. Can set it to 450f and it will never go above 450f. It will fire for a straight 10 seconds, since with temp control it will boost up to temp instantly with no voltage limitations. I don't see why you would want to fire it over

Could do multiple tcr profiles too. One for screen/herb temp just above screen.

BTW: I don't really plan on modding any mods for this.... maybe another project. The adaptor and tcr profiles for temp control to work whould be it for now. The adaptor will likely be made to work with any mod. But their are shady mods out their. My adaptor will have specifications, so will be up to you to meet them. Unless their are laws which limit me from doing this. And no, your screen will not blow or suffer any i'll effects cause of safety features built into the hardware.

 

[TommyDee]

0.14 ohms seems high. That's only about 8 amps at full cell voltage. A box mod with a lower limit of 0.1 may or may not work on the LB. Certainly not worth the price of admission on my end.
That Target Mini is a decent size for this. It too could use a flange to hold the fire button.

 

[scy123]

Sorry, probably losing interst here but.

Thats what the mod reports and mods need to know accurate ohms for saftey reasons. (Edit: also mods will check the ohms constantly while firing for saftey and to do temp control)

Full temp the whole way would not need a higher then 10s pull. Your batteries are just not putting out enough volts and needs time to heat up. Unlike mods that can heat up in a m/s

 

[TommyDee]

Interesting. If I ever get a 510 source that will confirm this, great. It would be nice to make the LB an actual temperature oven

 

[scy123]

That the primary selling feature. Acuurate temp control.

Edit: Also if you need to take longer then 10s pulls, your batteries are definitely underrated. It's hitting amp limits and can't put out the power it needs.

Amp limits, Amp draw, Ohm ratings, wattage at battery. Very important to know. I throw very important out their a lot so you may be sensitized, don't be. It could mean a battery blowing up if you don't know.

Edit: Also I can't find it to quote and was not gonna bring it up. But you seem to be trying hard to find ways my adapter won't work soo.... you mention you thermal runaway a few cells when using them. Obviously underrated for the application.

I never blew up any cells. and having cells blow up on consumer devices is a sign of failure.

 

[TommyDee]

Those thermal runaways were brand new AA silvers from MF. Their internal resistance was well over 0.2 ohms. They were definitely dangerous. And when MF replaced them, they replaced them with similarly dangerous cells. Now maybe you understand why I hit this Glyph cell search so hard. The cells with good internal resistance don't get hot.

And I absolutely want to get temp control for the MF but it is not something I can go spending a lot of money on to get there. I really can't go buying box mods only to learn they don't work. I already did that and good money is out the door and I have this cute little mini volt sitting here lighting up light bulbs. So my jest is not a lack of interest, it is the lack of vision in seeing a workable solution for the LB. So far, the Sub-C solution is the only reason I am still using the LB. This is what makes my LB rival the nuances of the VapCaps. I much prefer the taste and control you get with the LB. What I am most interested in having sufficient power available is how easy difficult it remains to avoid combustion.

10 seconds for a draw while modulating the cell is not a hard thing to do. I suspect that if I could provide a constant temp while drawing, that won't be an issue. The other intervention I often find myself getting mired in is the load that doesn't shake. All the duff just stays put in the screen after the first draw. This has to be disturbed or you stop getting vape although a lot of green remains.

Obviously my other problem is that I don't have fellow vapers to share equipment with. That would solve a lot of issues.

 

[scy123]

Those thermal runaways were brand new AA silvers from MF. Their internal resistance was well over 0.2 ohms. They were definitely dangerous. And when MF replaced them, they replaced them with similarly dangerous cells. Now maybe you understand why I hit this Glyph cell search so hard. The cells with good internal resistance don't get hot.

I did suspected AA would be underrated for the application based on calculations. I never tested and manufacturers don't list amp ratings on aa. So I never said anything.

If I see a market. I can actually test all AA and anything for true amp limits.

 

[TommyDee]

I got the Opus BT-3100 for this very reason. Had one before but it is lost somewhere. After seeing the numbers I pretty much understood the problem. I have 4 cells out of 20 that work, don't get hot, and have a very low internal resistance. 2 actually manage their capacity and the other two are gold Glyph cells that have about 1/2 their capacity. The gold Glyphs required recovery.

Whoever made those original Glyph cells knew what they were doing. The tech came from the height of minimizing junction resistance within Ni-Cads. Sanyo and Panasonic were all over this where Sanyo kicked Panasonic's butt. So where those Glyph cells came from only MF knows, but they are no longer available. Today they are using the Powerex cells which in my experienced opinion are junk. ...for the Launch Box. They work perfectly well for concentrate screens and Muad Dib.

 

[scy123]

I get a lot of battery info from Mooch the battery guru. I know he has a blog or something, but can't find the link.

Battery info is really important cause like I said..... even mfg claims can be off, need to test yourself.

 

[TommyDee]

Indeed. I got nowhere with MF. Basically, the tech for making the LB what it was is dead. Long live the LB with a Sub-C ...until someone puts a proven solution on eBay. I don't have the bandwidth nor the funds to pursue the 510 solution. I really need help on choosing box mods for this too.

Did you want to do a breakdown of your 510 adapter? I hadn't gone and looked at this without a wire. I don't do much with Muad Dib sessions but I can use the mini volt for that. I also got a couple of adapters that will fit the 510 so I can make contact. I'm pretty sure I can just 3D print the adapter for the cell. The adapter is almost made to be easily adapted

 

[scy123]

Was planning solid ss316l connections instead of wires. and 3d printed ultem 9085 around the whole thing. So you could literally fire a bullet at it and high chance of it still working. With spring on positive and adjustable lever on negative.
Only problem is how im gonna do the 510 thread. Their are easy solutions, but I wanted to make a really finished product.

BTW: lifetime warranty would apply If I made a new version. So if you wanted to exchange an old for new version you can do so without having it broken.

Edit: if someone could actually fire bullets at it and wanted to do so. I could send a few to test.

 

[OF]

That is a NiHM not NiCd and burst and continuous discharge is not the same. A lot of battery mfg like to trick you and try to claim burst like it was continuous. Notice they say "up to"?

Very true, 'specsmanship' sells stuff. Peak currents, held for tens of seconds can make for troubles. IMO you should design around typical duty, not max possible even though the LB in basic configuration does just that.

The LB, we're told, was designed to run at 15 Amps, with .75 Volts 'across the rails. The Thevenin (internal) 'source in the NiMH is 1.25 nominally, so have a Volt (1.25 minus .75) is 'lost', mostly to internal resistance (Thevenin again) inside the cell (which is why it heats).

I suggest you think in terms of current supplies, not voltage. This eliminates a lot of issues from the desigh. Design a circuit that delivers that 15 Amps (maybe up to 20 or a bit more), no matter the voltages involved (as long as they stay reasonable. This means you need a buck converter if you want to run anything over NiMH voltages most likely. You want to deliver 20 Watts or so (15 Amps times .75 Volts) nominally/. Maybe up to 30 if you're of that ilk. Simple buck converters, like we're using can be 80 or even 90% efficient.....can be, but like the battery specs above dig in. That's typically at a given load (usually close to max to cover losses in the running of the converter) with higher 'delta', that is with big voltages coming in. They always seem to have a diode drop added in, even if it's a hot carrier type that's close to a Volt? So to get our 30 Watts out we probably need a battery pack that will give us twice that on a continuous basis?

It's fun to consider that the basic version (single cell, carefully selected for ability to deliver 15 Ams continuously) is 'only' about 60% efficient overall. That is almost half the heat (power) we unleash ends up in the wrong place (inside the cell for the most part, but also the SS rails and random 'contact resistances), and most of that doesn't actually end up where we want it (in the small fraction of the load contacting the screen and making vapor). Heat produced elsewhere (say above herb line in the trench or a large fraction on the other side of the screen for that matter)

The design of the LB is linked to a specific cell (and all the losses), which has improved a bit over time. But, basically we're abusing the toughest AA on the market ATT.......big time. To our everlasting joy!

Regards to all.

OF

 

[TommyDee]

I have a few spare bullets.

I bought a few e-sig adapters that solved the thread cutting issue for 510. It has that very fine larger thread on the OD. This adapter is begging for a press-fit 'sleeve' though.

Clamping the unit in place will solve the other issues of making contact without pressure.

Thanks for weighing in @OF . I forgot to factor the internal heat as part of the capacity. Silly me. But yes, that is where that residual capacity goes. Sub-C has solved all my cell issues simply because it can handle this requirement with ease but the downside is the voltage limit. And that is where the PA comes in. The PA lets you participate in a session like the cells are always peeked. Then again, you already know this

And just to throw this even further over the fence... someone did say primaries worked. Haven't tested that yet but damn... 1.5V in!

 

[OF]

And just to throw this even further over the fence... someone did say primaries worked. Haven't tested that yet but damn... 1.5V in!

Probably me that's guilty there. I got some OK results with a couple models of D cells, for a while anyway. Again, some are capable of serious currents but flashlights are really designed around a Volt or so, often less, at the bulb even partway into their service life. The internal resistance rises rapidly, so you can still get 15 or more Ah out but only if you take it out slowly. Rewiring a four AA battery pack to put them in parallel also showed some promise since lower grade AAs could be used and offered longer run times than the same four 'one at a time' added up.

But the goal where you could buy an emergency battery at a gas station or convenience store when on the road is at least possible with Primary cells. PAs work better?

OF