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VapCap Induction Heater for Desktop and in Car Use

Discussion in 'DIY' started by Pipes, Nov 23, 2016.

  1. rz

    rz Well-Known Member

    Messages:
    103
    Make sure to use MKP capacitors. take a look at this mouser filter for more or less what you can use.

    The most direct effect of changing caps is the resonant frequency.

    Decreasing capacitance will increase the frequency.

    The biggest issue of a higher frequency is thermal load on the transistors, as they spend a larger portion of time in a less efficient state.

    The general power consumption also drops a little with lower capacitance (and efficiency decreases), so you don't want to go too low.

    It's nice to play around with, and there are a few noticeable difference in behaviour from heat penetration differences,, total power*efficiency, but the end results are pretty similar

    My build is currently using 2x0.22uF for 0.44uF total which I like. I've used a single 0.33 which also worked well, but the cap would get a bit warm.

    You could probably get away with 1x0.33 if you're using conservatively. I'd feel the parts for excessive heat, and would probably avoid taking it to any excessive use environments. Spreading the load over multiple caps is probably a better idea.

    The board I'm designing has space for 4x 0.15~0.22uF caps.

    Work has been busy as hell the last few weeks, but is quieting down a little now that we're over some large releases. I've neglected my induction project as a result, but I'm pretty much done designing my prototype board. I could keep designing for ages though its really a testbed so I don't need to over-over-engineer it. I've ordered the parts already. I just need to go over the board a final time and send it to get made :D In the meantime, my prototype is pulling along nicely, keeping me chillaxed through the last few weeks :cool:
     
  2. steama

    steama Well-Known Member

    Messages:
    3,000
    The Skeletor has landed at my house from the land of the maple leaf. What a wonderful piece of work. My first go with it felt like I was getting high with a ghost. I thought about a home for my new toy then I noticed my latte mug on my desk -- well, now it's a Skeletor mug.

    Thank you so much @Pipes for your ingenious and very effective little invention >>> I am really loving it.

    [​IMG]

    :cheers:
     
  3. StormyPinkness

    StormyPinkness Rhymenocerous ʕ•ᴥ•ʔ

    Messages:
    1,259
    Location:
    California
    Great thread, I really like the idea.

    Ah that's awesome, love it in a teacup.
     
  4. GreenHopper

    GreenHopper 20 going on 60

    Messages:
    725
    How do you take your tea? One click or two? :lmao:
     
  5. steama

    steama Well-Known Member

    Messages:
    3,000
    Man, oh man! As far as vapcap goes this damn thing changes everything. It's a whole nuther level of chill.

    Now my vapcap is also a premium 'portable desktop' vape too!

    :love:
     
  6. jane621

    jane621 Unapproved commercial account.

    Messages:
    14
    woderful!
     
    Pipes, Derrrpp, steama and 3 others like this.
  7. steama

    steama Well-Known Member

    Messages:
    3,000
    How does this induction device work with the vapcap 'M'? Being that the 'M' is all ferrous metal I wondered if it's induction performance was noticeably different than a vapcap using a Ti tip?
     
  8. grokit

    grokit well-worn member

    Messages:
    11,369
    Location:
    the north
    Very well indeed. The m takes a bit longer to heat-soak, but the flipside is that it holds the heat longer. I feel that it extracts better than the ti tip without scorching the load. For full-size one-hitters I'm starting to prefer the m for these reasons. These revelations came after I switched tips between my ti woody and my m.

    :sherlock:
     
  9. phattpiggie

    phattpiggie Well-Known Member Accessory Maker

    Messages:
    1,509
    I didn't notice much of difference in caps, now using Ti and it behaves differently.

    @grokit I'll stick with the Ti for now but after a couple of bowls I'm missing something, not had enough time with it yet but first impressions is the M has it for me.
    Enough heat is stored to get multiple tokes off one heat cycle or as you say plenty of heat for one hit with out combusting.

    I've combust with both tips.

    @rz all that went over my head, as does most of the stuff you've written about the work you're doing.
    But thanks any ways to yourself and @Pipes I'm understanding it all a bit more.

    A quick search on serial numbers on the capacitors made me realise they were high frequency and 'special'.
    I'd rather keep with the same specs. but was wondering about physical sizing.

    My next idea is to move the original ones.
    Mines the bottom right one, I'm thinking would it be possible to remove the caps. and put them elsewhere.
    As in either side of the two coils?
    That makes the induction PCB a little wider than the sled but about half the thickness, I can then put the PCB behind the charge board and batteries.

    The on board charging works a treat all 3 at 4.2v, and faster than my D2.
     
  10. Pipes

    Pipes Addicted DIY Enthusiast Accessory Maker

    Messages:
    1,882
    Location:
    Southern Ontario
    No problem moving components around to different locations however, we are dealing with some high currents so extending legs will need to be with decent gauge wire like AWG 16 minimal and keep as short as possible. You are doing a lot to gain very little in size.
    It might be better to consider @rz's approach and make the driver from scratch. Using the capacitor's legs for attaching the components. There really aren't that many discrete components and only 3 main power rails within the circuit. The pre-made board is just so convenient and cheap.
    It is possible to only have one oscillating coil but then you need two work coils. Like this one which is the same as what is being used here but needs two work coils which are not included. In our application though, the work coils can be gauged down as proven in my previous experiments. This is because of the short work cycles. Lots of time for cooling down. Again, big change for little gain.
    Interesting in efforts to scale the size down. I like where it could lead. :brow:
    :science:
     
  11. phattpiggie

    phattpiggie Well-Known Member Accessory Maker

    Messages:
    1,509
    Yourself and @rz seem to speak in a foreign tongue and I'm too long in the tooth to learn the lingo.:lol:

    Pretty pictures do it for me tho.

    If I move them either side of the coils I add 8mm to the overall width, the sled is 60mm.

    Taking them off the back of the board makes it 14mm thinner. I'll not get all 14mm as I need to keep the boards apart, but it takes it to a more cuboid than cube shape.

    I'll bend some solid copper cable I have which will also keep the caps. in place. Plenty of heat shrink as well.

    It would be interesting to see how small you could go with off the shelf stuff and how much smaller a custom build could end up.
     

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