Samsung 25R subohming

Discussion in 'Battery Junkies / Chargers' started by mdno, Feb 26, 2015.

  1. mdno

    mdno

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    How low ohm build I can build on these? Will these perform for example 0.05ohm builds? I'm just worried about only 20A continous output..
     
  2. nightshard

    nightshard It's VG/PG not PG/VG VU Donator Gold Contributor Member For 3 Years

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    0.21 min, 0.3 on the safe side, 0.05 no way.
     
  3. BigNasty

    BigNasty Diamond Contributor Member For 3 Years ECF Refugee

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    If you do not value your safety and are truly set on tard ohming 115% of the battery amp limit then sure go right ahead. What is the worst that could happen? (hint the least would be a vent worst a handful of Darwin. )
    I would not push one below .20.

    Honestly without knowing the in and outs of amp vs. drain safety you honestly should NOT go below .3
     
  4. mdno

    mdno

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    Okay thanks guys. But would vtc4 or 5 be able to handle 0.1ohm build?
     
  5. BigNasty

    BigNasty Diamond Contributor Member For 3 Years ECF Refugee

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  6. trlrtrash13

    trlrtrash13 Bronze Contributor Member For 3 Years

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    Depends on how you define "handle". If you mean is the battery meant for that, than no. No battery really is. If you mean can you do it and get away with it? Yes, but be careful. Make sure your mod is clean on the contacts, threading, and spring or magnets. Take short hits and pay attention to the mod. If you feel it heating up anywhere, stop. Monitor the battery closely. That setup will drain it very fast.

    Now that I was helpful, I feel obligated as a sub ohmer to say you really shouldn't do that. It's your call, and be careful if you do. .1 and under wouldn't fit the definition of "safe" with any battery.
     
  7. mdno

    mdno

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    Okay thanks a lot! I appreciate your help:). I think i stay above 0.2 ohms.. At this point I have 0.2ohm single zipper coil on my dark horse rda sitting on dovpo semimech with samsung 25r. Should be safe? And is there some other coil(s) that could produce a LOT of vapour? Sorry for little offtopic.
     
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  8. BigNasty

    BigNasty Diamond Contributor Member For 3 Years ECF Refugee

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    Run a set of parallels wide up the airflow.
    .2 above in that set up wide open should fog your face off safety.
     
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  9. mike-c

    mike-c Bronze Contributor

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    It's mostly a balance between heat and air. I get respectable plumes @ .6 ohms with 24awg kanthol.
     
  10. Sully

    Sully Silver Contributor

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    If you really want bigger clouds / more power, buy or make a dual 18650 box and share the love across 2 batteries. :)
     
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  11. mike-c

    mike-c Bronze Contributor

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    I agree in a way. It all depends on if the batteries are in series or parallel. If they are ran in series the 20 watt limit still stands to my knowledge.
     
  12. Sully

    Sully Silver Contributor

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    This is true. In series, you don't double your amp limit, just double the voltage. BUT you can achieve high wattages with higher resistance. For example:

    1x 18650 @ 0.1 = ~170watts (42A)
    2x 18650 @ 0.4 = ~170watts (21A) (Series)
    2x18650 @ 0.1 = ~170watts (42A) (Parallel)
     
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  13. VaperInDisguise

    VaperInDisguise New Member

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  14. mike-c

    mike-c Bronze Contributor

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    You the man Sully
     
  15. Sully

    Sully Silver Contributor

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    You must of missed the post right above the one you quoted where the OP asked about Sony's...
     
  16. VaperInDisguise

    VaperInDisguise New Member

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    Ah I was looking at the actual OP not off-topic answers :p
     
  17. mdno

    mdno

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    Yeah I have a box mod, semi mech thought.. difference to mech is the protections(short circuit, overload and overdischarge, batteries placed wrong, no builds below 0.2ohm etc.) Soo batteries are in series. I was asking those uultra subohm things cause I was getting a new mech mod cause that 0.2ohm limit was annoying. :D I just builded parallel dual coils @ 0.2ohms 5 wraps on 27awg KA1. Well, like it more than zipper coil, maybe because zipper heated so slowly..:rolleyes:
     
  18. Jackson

    Jackson New Member

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    Let's see we have a battery made by the #1 manufacturer in worldwide sales and used by the top high end, pro-line cordless tool manufacturers, Bosch, Milwaukee and Hitachi. If it makes you feel better Samsung now lists a 100A pulse rating.
     
  19. mike-c

    mike-c Bronze Contributor

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    Id have to see some real tests done before I'd believe that 100 amp rating before I'd even go above 20 with the way these battery companies over state and re-wrap. No offense to anyone in anyway though, it's just better to be safe than lipless.
     
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  20. Zamazam

    Zamazam Evil Vulcan's do it with Logic Staff Member Senior Moderator VU Donator Platinum Contributor Member For 3 Years

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    A VTC 4 or 5 can handle a.15 Ohm load with a little headroom left since they are 30 amp. I've done quad vertical parallels at .15, all the clouds you could wish for with a Troll RDA.

    With all that said, with the 25R's, stick to .2 upwards. If you want to blast some monster clouds safely, get a Sigelei 150Watt mod.
     
  21. mike-c

    mike-c Bronze Contributor

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    Also I'd be weary of vtc's at this point. They've been discontinued for some time. I was affraid of getting re-wraps so I just went with 25r's for all my boxes.

    There are ways to authenticate vtc's though, I just don't know how.
     
  22. Lefty

    Lefty Silver Contributor

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    Well yes - for 1 second. 45A for 5 seconds - 30A for 6 seconds. Or of course 20A continuous.
     
    Last edited: Feb 26, 2015
  23. Jackson

    Jackson New Member

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    Uh no.

    HKJ my fave battery tester/reviewer seldom tests over spec but here's his test of the Samsung 20R, a 22A/2000mAh cell.

    [​IMG]

    The 30A continuous test (yellow trace) is quite lovely and lasts a bit more than your mythical 6 second assumption.

    Now here's what a struggling battery looks like.

    This is the so-called 30A Sony (and Efest's rewrap of the same) at a continuous 20A drain, basically only 2/3rds of it's claimed spec (ignore the upswept traces they are temp readings.)

    [​IMG]

    Here's a close up. Note when it hits 3.2V , looks like about ~240mAh.

    [​IMG]

    If you check the Samsung running at about 33% OVER it's rating it manages ~500mAh, more than double the Sony.

    Just for the heck of it I'll through in a test of an Efest (BIO, Best-in-One as they used to called) .made battery, not one of their rewraps. They rate this one at 10A.

    [​IMG]

    In HKJ's tests he always tests 2 cells at a time. The Samsung's track so well it looks like one trace, a testament to high quality manufacturing and QC. The crap Efests are not even close.
     
  24. mdno

    mdno

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    I have used those parallel dual coils @ 0.2ohms for a day now and those doesn't produce vapour as good as single zipper coil @ 0.2ohms. Only things I hate at zipper coil is that it heats up so slow and needs a lot of juice, after two long hits.
     
  25. Lefty

    Lefty Silver Contributor

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    The cell under discussion was the 25R. I made no assumptions other than the 25R was the subject and that "Samsung lists" meant Samsung. I quoted the Spec sheet.
    https://docs.google.com/file/d/0BwO0M-Quz5OhbHZwR3MyWG9KU28/edit?pli=1
     
    Last edited: Feb 27, 2015

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