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Reversed battery polarity in mechs

Discussion in 'APV and Mods Discussion' started by SunRam, Sep 10, 2013.

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  1. SunRam

    SunRam Senior Member Verified Member ECF Veteran

    Feb 3, 2012
    South Africa
    Anyone with a mech had a overheated battery yet? I'm sure there's a lot of us. I'm using Panasonic cgr18650ch batts, and one overheated the other day, really heating up very quickly, and I subsequently chucked that battery just to be safe.

    Anyway, I read in another thread, due to this panny being uninsulated at the negative end, the body of a mech mod can make contact with the uninsulated negative end, causing a continuous fire, therefore heating the battery up (This happened to me with a K100 and cgr18650ch batt).


    The suggestion was made that one should insert these Panasonic batts wrong way round in mech mods (and especially the Chi-You clone), with the pos end facing down, to avoid this issue.

    So, is this the way to go? Anyone with some electrical current experience can chime in here?
    While I'm waiting for my vape safe fuses, I dont want to waste any more batts, or worse burn my face off!
     
  2. UncleChuck

    UncleChuck Ultra Member Verified Member ECF Veteran

    Apr 20, 2011
    Portland
    I would strongly suggest against putting the battery in backwards.

    I'll just copy my reply that I put in the other thread, it might have gotten lost in there:

    "On the subject of the backwards battery placement, it's really not a good idea. As was mentioned by someone else, the body of the battery is negative. With the battery in place positive side up, the body of the mod is the negative as well. If there is any sort of tear in the battery's wrapping, and it touches the wall of the mod, it won't be a big deal. It will simply complete the circuit (bypassing the switch) and power the coil just like you are pressing the button.

    If you have the battery reversed, the body of the PV becomes positive, but the body of the battery is still negative. If there is a tear in the wrapping, and it touches the wall of the mod, you will have a hard short. It will connect the negative body of the battery, to the positive body of the PV. This will be far worse than the previous scenario.

    Before a tear just resulted in bypassing the switch, this time a tear results in hard shorting the battery. Because the short is directly between the wall of the mod, and the body of the battery, there is nothing else to stop or break the circuit. Unless you catch this almost instantly you'll overheat and vent your battery.

    We're all adults here and I'm not trying to tell anyone what to do, but it's a really bad idea to put the battery in backwards."


    If you want to continue using those batteries, you could try to insulate the negative side of the battery, or insulate the end cap area on the mod. You could get some heat shrink tubing and add an inch or so on the end of the battery. Let about a third of it hang off the end, and when you heat it it should wrap around the base of the battery just like the wrapper on other batteries.

    You could also try using a plastic washer on the end cap to isolate the outer edge, although the shrink wrap idea is probably best.
     
  3. Papadragon

    Papadragon Senior Member Verified Member ECF Veteran

    May 3, 2013
    Omaha Nebraska
    Use black electoral tape around the bottom of battery thus making a insalator for bottom of battery prob solved and depending on the resistance of you atty the battery will heat up That is normal I sub ohm and as long as your battery can handle the amps your fine it will heat up any battery
     
  4. Aphex13

    Aphex13 Senior Member Verified Member ECF Veteran

    Jul 28, 2011
    Wiesbaden, Germany
    You've got this all backwards. I'm at work, so all I have to ilustrate this with is MSPaint, but I'll post a picture. It makes alot more sense if you're looking at it. if the body of your battery shorts with the body of the mod, and your battery is (+) to atomizer, you've got a complete circuit without activating the switch. If you put your battery in upside down, the switch is much closer to the (+) terminal. If your battery body was to short in this situation, the only time the circuit would be complete would be when the switch is pressed.

    (Edit) And I can't upload pictures from work. I'll draw a couple when I get home...
     
  5. Baditude

    Baditude ECF Guru ECF Veteran

    Apr 8, 2012
    Ridgeway, Ohio
  6. Richard75

    Richard75 Super Member Verified Member ECF Veteran

    Nov 23, 2012
    Pennsylvania
    I think I've got this down... it all has to do with the direction of the flow of the electricity. Someone please tell me if I'm wrong, but here's my explanation.

    Here are two scenarios:

    Molly puts her battery in positive up, towards atomizer. The electricity naturally flows from the positive side of the battery, up the center post, through the atomizer and down the walls of the PV until it reaches the button and, subsequently, into the negative side of the battery. If there is a tear in the wall of the battery and it makes contact with the interior wall of the PV, the electricity still flows naturally up the center post, through the atomizer, down the wall of the PV, but instead of grounding at the button, it grounds a bit sooner at the tear. The electricity still flows through the atomizer. Hence, Molly is just dealing with a completed circuit.

    Billy puts his battery in upside down, positive towards button. In this case, the electricity flows through the button, up the wall of the PV, into the atomizer and grounds at the positive post of his PV. If there is a tear in Billy's battery's wrapping, the electricity goes through the button and immediately grounds on the wall of his PV (before it can hit the atomizer), creating a hard short. Billy is not too happy when this happens.
     
  7. the4thpower3

    the4thpower3 Super Member Verified Member ECF Veteran

    Mar 30, 2010
    Northern Virginia
    Wrong - electrons from from the Anode (Negative) to the Cathode (positive) no matter which way it is facing.
    The body of the device is not a ground. This is a DC circuit.

    Yes, the casing of a battery is part of the Anode - which is why it has a protective sleeve/casing.
    If the batteries sleeve/casing is damaged/exposed it will cause a short as soon as it is inserted into a mech device positive up (once the anode touches its contact point).
    If the battery sleeve/casing was damaged/exposed and the battery was placed the device negative up - it would not short until the circuit is closed (ie. the button in depressed and makes contact with the positive).
     
  8. Aphex13

    Aphex13 Senior Member Verified Member ECF Veteran

    Jul 28, 2011
    Wiesbaden, Germany
    Billy's electricity would stop at his button, unless he presses it.
     
  9. Richard75

    Richard75 Super Member Verified Member ECF Veteran

    Nov 23, 2012
    Pennsylvania
    Damn physics, you win again! I bite my thumb at thee.
     
  10. SunRam

    SunRam Senior Member Verified Member ECF Veteran

    Feb 3, 2012
    South Africa
  11. the4thpower3

    the4thpower3 Super Member Verified Member ECF Veteran

    Mar 30, 2010
    Northern Virginia
    It's not an opinion it's fact.

    Opinion on whether or not to insert a battery "backwards" - don't do it if you don't understand the mechanics of your device or how a battery functions.
     
  12. Thrasher

    Thrasher ECF Guru Verified Member ECF Veteran

    Oct 28, 2012
    Madeira beach, Fla
    the way the bottom firing mech works it is reasonable to see how a reversed battery would be ok.

    but in my opinion i would just get different batteries and if you cannot reasonably expect a mod to work correctly with any battery then it wasnt designed correctly. personally i couldnt feel safe knowing the mod could fire at anytime.
     
  13. Aphex13

    Aphex13 Senior Member Verified Member ECF Veteran

    Jul 28, 2011
    Wiesbaden, Germany
    I know the pictures are really bad, but you get the idea. A short in the picture with the battery reversed is bad because it's a direct short. The atomizer is not in the circuit to take any of the load, but the circuit is open until the button is pressed. I'd think you'd notice some heat before the battery went critical, and let go of the button, but I'm not an expert. Always use the twist ring, button lock, or whatever, when you're not using your PV.

    With the positive end up, the short takes the switch out of the picture. If your PV is in your backpack/pocket/purse/whatever when the short happens, you have no way of knowing, or opening the circuit without taking the battery out of the hot mod. The atty is there in this situation to take some of the load. An atty may even pop sort of like a fuse, depending on what gauge wire was used to make it, but it might not.

    Both situations have ups and downs, but the chance of the whole chain of events starting in my pocket/backpack without me knowing scares me more than having to let go of my switch.
    People really should read up on the way their MOD functions, especially mechanical mods. There's a lot of safety features that are sacrificed when you go completely mechanical, but it's not hard at all to understand how they work.
    Untitled.jpg Untitled 2.jpg
     
  14. UncleChuck

    UncleChuck Ultra Member Verified Member ECF Veteran

    Apr 20, 2011
    Portland
    I think the opinion comes when deciding which is more dangerous.

    "right side up" the risk is a PV that will fire on its own without pressing the button. But it will still only draw as much current as the coil you have installed will allow.

    "Up side down" the risk is a PV that experiences a hard short when the button is pressed, causing very high load and more damage to the battery.

    Personally I feel the risk of a hard short is more dangerous than the risk of an auto-firing device. Just personal preference I guess.

    Your absolutely correct about the upside down battery not shorting unless the button is pressed, but the rest should be accurate.
     
  15. H. Hodges

    H. Hodges Senior Member Verified Member ECF Veteran

    Sep 5, 2013
    Spopkane, WA, USA
  16. BardicDruid

    BardicDruid Ultra Member Verified Member ECF Veteran

    Jul 25, 2009
    Central Texas
    Apparently none of you have ever peeled a battery, do it once and you'll stop worrying about the body shorting to the mod. If your beating up your batts bad enough to damage the cover, you're going to have problems anyway. If the batt casing is damaged enough to short, with pos to atty it won't shut off, with neg to atty you'll probably weld your switch in the on position and the atty won't fire. The simple fact is in a full mech mod it doesn't matter, if the casing is damaged, toss the batt.
     
  17. SunRam

    SunRam Senior Member Verified Member ECF Veteran

    Feb 3, 2012
    South Africa
    To some it up:
    Reversed = no teeth if something goes wrong :p
    Right way round = hot fingers if something goes wrong

    Thanks guys!
     
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