The Magic-Flight Box

[scy123]

Oh, 0.056 ohms is like the lower limits..... I know my mod will fire way lower but some might not be able to.

Battery chemistry don't matter as long as they can provide sufficient volts/amps. Would have to do a lot of testing, which is why I want to see if worth.

Strange imgur is now denying me too. I'll upload somewhere else later.

Edit: seems you need full link for imur to work. Try copy and paste address.

 

[TommyDee]

A lot of current box mods will go down to 0.05 ohms. Finding ones with appropriate firmware may be worthwhile.

Actually I've learned that the LB challenges the internal resistance of cells. Sub-C high drain; no issues - AA high drain; issues!
Glyph cells was a thing of their time. Now minimal self discharge is a thing. And because of that, low internal resistance has suffered in technology.
I have enough cells and the means to test them to know for certain this is the primary problem with making a LB a heavy hitter on batteries. And how I know that the Muad Dib doesn't suffer the same issues. The internal resistance of the cells they sell today is well under the 0.2 ohms of the Muad Dib circuit.

 

[scy123]

Can actually do custom firmware.... was kinda headed that way.

 

[TommyDee]

Potentially interested but your image doesn't work. What form does the connection between the mod and the LB take? Needs a cable, IMO; I'd like it if it was long enough to keep the mod in-pocket while the LB was in use.

I'd suggest MF's power adapter with a remote 12V battery pack. very pocket-able. That is what I was doing before making the brute cells.

@scy123 - Now were talking Yes, the dual button push stopped me from making mod adapters. I did run my poor man's Muad Dib with the box mod I have. It was way to fiddly.

 

[scy123]

Might be able to program it to switch on with button and switch off with button. Kinda advanced and I don't know how risky that would be. Would need testing.

Also, the adapter would be just that for now.... not this advanced.

 

[TommyDee]

I think a connection between box mods and the LB would do well on eBay. MF is still pretty popular for the curious like myself. I can tell you, I still love the nuances available with the LB. Power options has been my only peeve until now.

If nothing else, one could marry an 18650 or 14500 power pack with the internal workings of the MF PA3.0 and make this pocketable. Essentially, the PA is a purpose built box mod that doesn't have its own power.

 

[scy123]

Was thinking about an adaptor you can put almost any li-ion in and work, with adjustable temp/wattage/volt on the adapter.

That will probably never happen though, don't really see too much demand for that.

 

[TommyDee]

I see it as 'expensive' for the LB. But it can be as simple as a PA and a battery pack repackaged in a 3D printed case. The problem is the long cord. The losses are significant over a longer wire. Even my PA-v1.0 gets quite warm at the puck which is also way too heavy. Now you understand why I went for a "palm-able" solution. I can't palm 3x 18650... 1x 18650 maybe but it would need a serious converter. I'd like to see what that looks like in a converter. Basically a simple mod capable of up to 20 amps into 0.05 ohms with a 10 amps 3.6V input and regulation to manage the cell's peek of 4.2V.

What about screwing in the connection by adding a helical thread to engage the rail's loop? Then the LB press will be eliminated. leaving fingers free to operate the box mod.

What I find annoying with the PA-v1.0 is 1) I've dropped that cord way too many times when shaking the LB. And 2) The bulk. I can't manipulate the LB when connected to a wire. Shaking and maximizing the load takes a bit of dexterity, which in turn requires the freedom to move. Even with the sub-C, I find myself removing the puck to brush the trench about 1/2 the time. However, actually drawing on it and shaking the box in general is as simple with the sub-C as it was with the Glyphs. It's just a natural progression.

Box mods will add session specificity which would be way cool when you have the space for it.

 

[scy123]

If you make something with lipo built in it could be really small..... I don't wanna deal with lipo though. Or any built in batteries for that matter.

BTW my mod showed 1.5a when using the mlfb oil/dab version at operating wattage. https://i.imgur.com/oioKMVZ.png That's really nothing......

 

[TommyDee]

Correct. The Dib trench is peanuts. 5 watts will get you serious clouds. I see well under 200 milli-ohm internal resistance consistently on current cells. I only have a few cells that come in at under 50 milli-ohm internal resistance. Those work nicely on the full sized trench but not long enough. We need about 1.5 - 2 watt/hours to fully char a trench.
Li-Ion is still more power-dense than Li-Po. Never been a fan of LiPo. Considering I am looking at outdoor IH and on-demand logs, remote power is something that interests me.

 

[scy123]

I tested the amp draw of the battery on a dual 18650 mod with a resistance similar to the .05 ohms of the regular mflb. https://i.imgur.com/7UcWP1f.png

I don't know how to calculate amp draw with a regulated mod cause it's different. So I rely on hardware. And it might be different from mod to mod. 1.5v @ 0.05hms = 45w. I put 45w on the mod and it shows 7.25amp draw from battery. I am not sure it it means from each battery or both combined.

Was gonna test, but wanted to let you know how much amps you would need.

 

[TommyDee]

I did one test that you need the data from. I used the PA and measured the voltage at the rails. I got 1.15V being delivered to the stainless rails at full power which is way more than cells deliver. This measurement removes all other losses but accounts for the rails. The open voltage for the PA v1.0 is 1.8V. I don't think they are doing current regulation

 

[scy123]

Amp draw is really important to know when having portables. Sorry, I probably drifted away from what you were thinking hehe

BTW: internal resistance don't matter with mods they send a straight voltage to the mflb. set at 1.5v send straight 1.5v.

Edit: oh you where trying to say my mod won't work cause of internal resistance. The mflb only uses 45w. Mods go upto 300w. 45w is peanuts. Again if you set it at 1.5v it will push 1.5v till the battery dies.

 

[TommyDee]

True, but don't overlook contact resistance with stainless steel. That seems to be what killed the fuses. The center contact got very hot at the nickle/stainless steel interface. When I made that straight copper, no issues with heat whatsoever.

I could only check the input current when I achieved the 1.15V test. But then you'd need to know efficiencies as well. I've posted that back a few pages. you will find the actual resistance of the screen to be much less than 0.056 ohms. That is just what it ends up being when you add the resistance of stainless rails.

 

[scy123]

Was planning on a way for it to hold connections tight. Would actually be required for temp control to work.

probably an adjustable lever.

 

[TommyDee]

You need axial pressure and some radial pressure. That is why I was thinking a course fitting screw thread. Something very subtle but definitely grips the loop-contact and has an electrical spring contact in those threads.

The diameter I settled on for reliable loop-contact was dia. .56".

 

[scy123]

BTW if you are doing straight battery and no buck or boost converter. Could just use ohm's law. 0.05ohm at 1.3v = 26a. You need cells at 26a..... ideally higher.

 

[TommyDee]

I hadn't measured the voltage at the rail contacts yet using these cells. These cells are very capable of pushing juice being from the RC world but usable capacity at these levels are seriously diminished. The 3800mah cell struggled to complete a trench to near-blackness. 4200mah cells are keeping up with the caveat of minimal losses. 5000mah cells are available and recommended. Capacity obviously deals with usable responsive activation which makes the launch box great. Youncan always get a puff from the NiCads but that's not the point.

Anyway, I'll see what these cells deliver on voltage. Too many losses to get a good resistance measurement. That would require the sensing and analysis of your box mod that can handle loads at 0.05 ohms. I believe we are aiming at 1V at the rails for cells. 1.1V would be awesome! This is the very reason for the short lengths of wire. 14 awg on the core wire would be nice but a bit harder to implement in my wand solution. Keeping the 'switch' functional as a switch is key in my wand. I still have dexterity on my side for good contact. By my calculations we are operating in the range of 15-20 watts. 1/.056 - cell / 1.15/.056 - PA. The PA works very well with 3x 18650 and still outperforms single Ni-Cd/Mh cells.

 

[scy123]

The 3800mah cell struggled to complete a trench to near-blackness. 4200mah cells are keeping up with the caveat of minimal losses. 5000mah cells are available and recommended. Capacity obviously deals with usable responsive activation which makes the launch box great. Youncan always get a puff from the NiCads but that's not the point.

Your cells may be under rated for the mflb.

I calculated mines would last hours of firing. That was the dab/oil version. Lemme estimate how long this can last on a regular mflb.

 

[TommyDee]

To do the math justice, you need to know where on the discharge curve unacceptable voltage levels commence. The knee of the curve kind of blurs on Ni-Mh at anything over an amp. I asked Tenergy for that data and they wouldn't provide it. They are one of the few players left for the hobby and power cell scene. Basically you can look at Ni-Cd capacities for usable levels out of Ni-Mh. The Dib trenches will last days if not weeks on a Tenergy cell. Don't forget about the peek charge in your calcs. Those discharge curves really are important. I was bummed they couldn't provide them. They did confirm their 5C discharge rating however.

 

[scy123]

Sorry, I don't have a regular mflb but for my muad dib....I took a 5.6s puff and it wasted 7.9mWh according to my mod https://i.imgur.com/7UcWP1f.png = 0.017Wh that puff or ‭0.003Wh a second or ‭10.8Wh an hour.
a single 18650 has around 10+- WH. So it will last a straight hour. My puffs are like 10s max so like 300+ puffs.

Sorry the above is wrong. It was suppost to be a pic of the muad dib, but seems I mixed the pics. that is a pic of the 45w regular mflb with 0.05ohm screen. I can't approx runtime from that as it fired too short.

Too much work, gonna just forget the runtime estimate till I figure out if I wanna make this or not.

BTW: it don't matter what the li-ion voltage is. It's a regulated mod it will send straight 1.5v or whatever till the li-ion battery dies.

 

[TommyDee]

I concur with your findings. Your electric bill would go way up on the LB Teasing out that last bit of vape spirit from flower takes a lot of energy in the LB. That is the price of conduction with flower. And at that point in the session is when you need voltage. But a fresh peek charge near the end of the session -will- cause combustion. Very delicate balance indeed.

 

[scy123]

BTW: a 4200mah cell with a 5c rating has a 21 amp limit. 0.05ohm at 1.2v = 24a it's trying to draw. You are hitting the amp limit and the battery is just not putting out as much voltage as it should.

 

[TommyDee]

we're not pulling 24 amps. easy calc -12v@2a source power to AP v-any. that is more power than the cell provides. Argggh, I don't want to fry this new LB on a peaked cell without a load. This is a hard measurement to get.

Basically what I've been getting at is that voltage is lost along the way. Junction resistance at high currents, under-gauged wire lengths, insufficient contact area... all those factors outside the rails contribute to significant losses. Therefore the full circuit resistance is much greater, bringing our actual draw to about 15 watts. And at 1V at the rails, that is 15 amps.

 

[scy123]

Sorry, I kinda lost you... you are powering a 12v PA with car adapter connected to a battery or something?

The voltage lost along the way does not get lost.... the battery still needs to supply it. 1.2v@0.05ohm is 24a at battery still. Underrated batteries are not a good idea. You will lose voltage under load and a potential for thermal runaway = fire/explosion

Edit: forgot to mention using a buck/boost converter works differently. Don't really know what you have planning.... sorry I don't read all post. But you have to know amp limits and draws. I can't stress this enough. Not knowing = fire/explosion

Edit: I just checked 1v at rails = 20w and 20a on a 0.05ohm screen. The battery will be putting out more amps and you mention the screen is acually below .05ohms.... the lower it goes the more watts/amps you're using.