Samsung 35E 3500mAh 18650 Bench Test Results...a so-so 8A battery

Discussion in 'Batteries and Chargers' started by Mooch, Nov 7, 2016.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    These cells were purchased with funds donated by the vaping community for the purposes of testing. Thank you! To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18350, 18650, 26650, etc.

    While the test results are hard data, the conclusions and recommendations I make based on these tests are only my personal opinion based on my criteria for setting a rating. Carefully research any cell you are considering using before purchasing.

    Testing cells at their limits is dangerous and should never, ever, be attempted by anyone who has not thoroughly studied the dangers involved and how to minimize them.

    If the cell has only one current rating number on it, or if it says "max discharging current" then I have to assume that the company is stating that the cell can be discharged at that current level in any way, including continuously.

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    Bottom Line
    This battery has a very high 3500mAh capacity rating but even at just 5A its run time down to 3.2V is a lot shorter than the 3300mAh Panasonic NCR18650GA. Its high internal resistance causes a lot of voltage sag which triggers a regulated mod's weak battery alert sooner than batteries like the NCR19650GA and MJ1. I am rating it at 8A/3500mAh. My maximum vaping amps (MVA) rating is 13A but at anything over 10A or so there is a lot of battery sag.

    The 18650 ratings table has been updated to include this cell.


    Continuous-Current Test Results
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    Pulse-Current Test Results
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    Comments
    • At 5A continuous it reached about 3126mAh. This is about average performance for a 3500mAh cell at 5A so I am rating it at 3500mAh.
    • At 10A continuous the temperature rose to 74°C. This is just below the average temperature of a cell operating at its continuous discharge rating (CDR) but there is significant voltage sag. This is an indication that we are operating at above its true rating.
    • At 15A continuous the temperature rose to 109°C. This is above my 100°C safety limit and, along with the severe voltage sag, shows that this cell is being operated at far above its true rating.
    • I am setting a CDR of 8A for this cell. While operating any cell near its rated maximum current level causes damage to the cell, I would expect good cycle life from this cell at 8A continuous.
    To see how other cells have tested and how hard you can safely push them, check out these links:
    List of Battery Tests | E-Cigarette Forum
    https://www.e-cigarette-forum.com/f...afety-grades-and-pulse-performance-data.7566/
    https://www.e-cigarette-forum.com/f...des-picking-a-safe-battery-to-vape-with.7447/
    https://www.e-cigarette-forum.com/f...fety-grades-and-pulse-performance-data.7554//
     
    KenD, MikeyConti, Clark Kent and 2 others like this.
  2. Michael_Casper_

    Michael_Casper_ Full Member

    Apr 30, 2017
    Hi Mooch,
    So I bought two pairs of these to use in a regulated box mod (Wismec Predator 228). I'm a bit concerned about your 8A rating. Are these safe to use in regulated devices, and what would the limits be for wattage etc as a pair? Thank you for everything you do! We need to get you back on the Vaping Biker's channel for another interview! Thanks for any help you can provide.
    P.s. I am considering purchasing my first mech tube, but cannot find VTC5A batteries in Stock at the moment. Would you recommend Samsung 25R or another cell as a compromise?
     
  3. Topwater Elvis

    Topwater Elvis Vaping Master ECF Veteran

    Dec 26, 2012
    Texas
    They would be a very poor choice for your power device, great flashlight cells.
    Most would recommend at least 20a CDR cells for use in power devices like yours.

    Plenty vtc5A's in stock, of course dependent on where in the world you are.
     
    KenD likes this.
  4. Michael_Casper_

    Michael_Casper_ Full Member

    Apr 30, 2017
    I'm in the USA, AZ to be exact. I usually purchase from illumn.com, but they're on backorder...
     
  5. Topwater Elvis

    Topwater Elvis Vaping Master ECF Veteran

    Dec 26, 2012
    Texas
  6. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Any battery is relatively safe to use in any device as long as you don't abuse it. :)

    These ultra-high capacity batteries are very inefficient above 5A-7A or so when compared to ones like the VTC6, 30Q, or HG2. The 35E's are ok up to about 20W each, 40W in a two battery device, etc.

    There are VTC5A's out there. Check IMRBatteries, Liion Wholesale, RTDVapor.
    The 25R is a good battery. Check my blog for my recommended batteries table for other possible alternatives.
     
    KenD, WillyZee and Michael_Casper_ like this.
  7. Michael_Casper_

    Michael_Casper_ Full Member

    Apr 30, 2017
    So, at 65-80W am I just losing battery life, or is this dangerous?
     
  8. Topwater Elvis

    Topwater Elvis Vaping Master ECF Veteran

    Dec 26, 2012
    Texas
    Wismec recommends ( " discharge current should be above 25a " ) for the predator on their site & in instruction/user manual.

    When quality cells with sufficient amp rate are so readily available & inexpensive why do you want to use cells that could be severely limiting or problematic.
     
  9. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Using a battery is less safe than not using one.
    Using a battery at beyond its recommended limits is less safe than staying below the limits.

    Only you can say if it's dangerous or not though as you have to set the thresholds for the risk you're willing to take.

    Think of cars. Driving at 70mph...is that inherently dangerous? Or is it just possibly less safe than 55mph (which is less safe than not driving at all). Some people would never consider going past the speed limit. Others do it regularly. All depends on their personal decisions.

    A battery can't vent though until its wayyyyyy over the boiling point of water. It can't go into thermal runaway unless short-circuited or run at a level that makes it think it's being short-circuited.

    At 40W with a 35E battery you're at about 14A worst case. Pretty crappy performance at that level but your battery shouldn't vent even if there is a continuous misfire.
     
  10. Michael_Casper_

    Michael_Casper_ Full Member

    Apr 30, 2017
    I don't want to continue using them. I already placed an order for 4 VTC5A cells, but wanted to make sure my batteries weren't going to explode in the meantime. Also, I have a friend who bought some 35E's and he was worried too. I must sound like a complete idiot to you guys, but that's why I came here for advice. I have one pair of HE2's that weren't married (they were rotated in single 18650 mods) that I'm using since you scared me off of the 35E's. But that's my only other option until the VTC5A's arrive.
     
  11. Michael_Casper_

    Michael_Casper_ Full Member

    Apr 30, 2017
    Thank you Mooch, like I said I am here to learn. I don't usually vape above 85W, and my usual is between 65-75. However, a friend of mine also has these batteries and he vapes over 100w regularly. Neither of us chain vape, but it's still scary to find out the batteries you're using aren't rated for that application. Thank you again for all the info, and helping me along.
     
    Mooch likes this.
  12. Topwater Elvis

    Topwater Elvis Vaping Master ECF Veteran

    Dec 26, 2012
    Texas
    I apologize if my responses seemed brusque.
    Sound like an idiot?, No, quite the opposite.
    You asked good questions about batteries, something too few beginning vapers with high power devices do.

    Battery saftey is not something to take lightly, even using name brand quality cells sometimes a scenario presents itself just right for bad things to happen, sure it is rare, but can happen.
    How often? how severe? impossible to quantify, if you go around pushing luck, sooner or later luck may push back.
     
    KenD and Michael_Casper_ like this.
  13. Barkuti

    Barkuti Senior Member ECF Veteran

    May 3, 2016
    Wisdom is the true essence of safety fellows. :)
    Don't abuse your batteries and you'll always be fine.

    More or less recently someone pulled a couple of cells out of laptop pack, inserted them in a regulated mod and dialed “120W” to briefly after complain about “low performance”. Can't really recall precisely what happened, just gave it a quick peek and intervention, and a mod closed the thread. However, please understand that, due to the extreme voltage sag (Vout = Vnoload - (I × Rbatt)), doing this can't be precisely considered “unsafe” because the cutoff bell of the mod will instantaneously ring (LoL!). Can't really say how your regulated mods work, but in BMS equipped batteries this means instant shutdown. :thumb:

    In terms of efficiency and lifespan, I like to divide the maximum continuous discharge current by √2. Considering the output power dissipated in a cell/battery is P = I² × Rcell, it is easy to understand we are dividing the “heating ratio” in half by doing this (half thermal stress). For a 20A cell, this means a tad above 14A. Another way: multiply by half of √2. :2cool:
     
  14. Michael_Casper_

    Michael_Casper_ Full Member

    Apr 30, 2017
    Hey Elvis, I just thought of another question about these cells. You mentioned great for a flashlight, but how about using them in a coil master 521 tab? I'm sure they would do fine for reading the ohms, but how about pulsing for glowing contact coils etc? Thanks again!
     
  15. Topwater Elvis

    Topwater Elvis Vaping Master ECF Veteran

    Dec 26, 2012
    Texas
    I wouldn't use them in a coil master / ohms checker box that is capable of firing the coil.
    The amp draw on the battery is the same wether used in a power device to vape or in an ohms checker that fires the coil.
     
    KenD likes this.
  16. Michael_Casper_

    Michael_Casper_ Full Member

    Apr 30, 2017
    That's pretty much what I figured, just wanted to check. Thank you!
     
    Topwater Elvis likes this.

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