Sony VTC4 2000mAh 18650 Retest Results...a great 23A 2100mAh battery

Discussion in 'Batteries and Chargers' started by Mooch, Mar 14, 2016.

Thread Status:
Not open for further replies.
Image has been removed.
URL has been removed.
Email address has been removed.
Media has been removed.
  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

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


    Disclaimer
    The statements, conclusions, and recommendations I make based on these tests are only my personal opinion. Carefully research any battery 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.


    A note regarding current ratings and my testing
    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 continuous.

    image.jpeg image.jpeg image.jpeg image.jpeg


    Bottom Line
    This is a hard hitting 23A continuous battery that exceeds its 2000mAh rating. They were purchased from www.illumn.com and are are identical in appearance and performance to genuine VTC4's. They run much too hot to be rated at 30A continuous but their temperature at 23A is the same as the VTC3 and VTC5 at their ratings. The VTC4 hits harder than the LG HB series of batteries but it runs hotter. Can you vape with it at 30A? Of course! It can be pulsed at up to about 50A before its voltage gets uselessly low.


    Why the VTC4 is not a 30A cell
    • The VTC4's temperature when discharged at 30A continuously is almost 100°C. This is over 15°C higher than any battery is allowed to get at its rating. The VTC3 and VTC5 are about 82°C at their ratings. The Samsung 25R is about 78°C at its rating. Most of the LG's are about 82°C at their ratings. At 23A continuous the VTC4 is the same temperature as the VTC3 and VTC5 at their ratings.
    • At 23A continuous the nominal voltage of the VTC4 is about 3.2V. This is close to the nominal voltage of other good cells at their ratings. At 30A continuous the VTC4 runs at a much lower voltage than other cells at their ratings, indicating that 30A is above the VTC4's rating.
    • Section 7.2.4.3 of the VTC4 datasheet states that the "Over current protective circuit" shall not allow the VTC4 to be discharged for longer than 80 seconds at 30A-40A. If the VTC4 was a 30A cell it should easily be able to be discharged continuously without being stopped.
    • The table in section 7.2.4.3 of the datasheet, showing timing for discharges up to 150A, is not a table of what the VTC4 can do! This is a table to show manufacturers incorporating the VTC4 into their products how the battery management system (BMS) must function. The current levels in this table are emergency situations for the BMS to respond to, not cell ratings.
    • Section 7.2.4.4 of the VTC4 datasheet states that the "over temperature protective circuit" shall not allow the VTC4 to exceed 80°C. But in Sony's discharge graphs and my tests the VTC4 reaches almost 100°C at 30A continuous. If the VTC4 had a 30A rating it would not need the battery management system to shut off the current if 30A was flowing.
    • Section 2 of the datasheet, "Cell Rating", has a rating titled "Continuous Maximum Discharge Current". This is not the continuous discharge rating (CDR) for the VTC4. It is the maximum discharge capability for the battery before the BMS shuts off the current flow.
    • The Sony Technical Information document for the VTC4 has a Cycle Life Performance chart for 10A and 30A discharges. But the discharges have a temperature cutoff ("Tcut") of 75°C. Since the discharge graphs in that same document show that the VTC4 reaches almost 100°C when discharged at 30A this means that each of the 30A discharges for the cycle life performance test were stopped before the battery reached empty. This was done to prevent accelerated damage to the cells caused by high temperatures and shows that 30A is not the rating for the VTC4.

    Continuous-Current Test Results
    image.png


    Pulsed-Current Test Results
    These tests are done to show the performance of the cell at higher pulsed current levels. If you are running your mod at these levels be aware that you risk overheating, and possibly venting, the battery if there is a malfunction or accidental pressing of your mechanical mod's button.
    image.png image.png


    Sony datasheet ratings and graphs
    See the next post as I'm over the limit for the number of graphics in a single post.


    Comments
    • At 10A continuous it reached about 1975mAh. This is fantastic performance for a 2000mAh-rated cell operating at 10A so I am rating this cell at 2100mAh. This is the nominal capacity rating for the VTC4 so my results are typically what you will get.
    • Its temperature at 15A continuous was 64°C, significantly below the average for a cell operating at its CDR.
    • At 20A continuous the temperature rose to 77°C. This is about the average for a cell operating at its CDR.
    • At 25A continuous the temperature rose to 88°C. This is significantly above the average for a cell operating at its CDR.
    • At 30A continuous the temperature rose to 97°C. This is much, much too high a temperature to set this current level as the CDR. It is clearly not a 30A cell.
    • At the 35A continuous the temperature rose to 104°C, exceeding my safety limit of 100°C.
    • I am setting a CDR of 23A for this cell since at this current level its operating temperature is at the average for a cell operating at its CDR. While operating any cell near its rated maximum current level causes damage to the cell, I would expect decent cycle life from this cell at 23A.
    • I have included pulsed discharges but I haven't set pass/fail standards for pulse testing yet. The discharges were done at 5sec on/30sec off, down to 2.5V. One chart shows the entire discharge at each level. The other chart is zoomed in to show the first 5 minutes to make it easier to see the voltage sag at different current levels.

    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
    18350 Safety Grades and Pulse Performance Data | E-Cigarette Forum
    18650 Battery Ratings -- Picking a Safe Battery to Vape With | E-Cigarette Forum
    26650 Safety Grades and Pulse Performance Data | E-Cigarette Forum
     
  2. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Sony datasheet ratings and graphs
    image.jpeg image.jpeg image.jpeg image.jpeg
     
  3. sonicbomb

    sonicbomb Vaping Master Verified Member ECF Veteran

    Feb 17, 2015
    1187 Hunterwasser
    It's nice too see some cells with good performance coming out of the Mooch test lab, as opposed to moody re-wraps.
     
    Mooch likes this.
  4. Vaslovik

    Vaslovik Account closed on request ECF Veteran

    Jul 5, 2013
    Thank you for this :)

    Those are the batteries I'm using, also got them from www.illumn.com, and I have no complaints about them at all. I have 12 of them.
     
    Mooch likes this.
  5. WharfRat1976

    WharfRat1976 Vaping Master Verified Member ECF Veteran

    May 31, 2014
    Austin, Texas
    Was waiting for this one Mooch. Yes they do run warm. I get around 100 cycles or less before they really lose their charge.

    I recycle them when I charge them full, retest them a day later and they are at 3.5v without using them.
     
    Tim Jenson and Mooch like this.
Thread Status:
Not open for further replies.

Share This Page