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Single Tesla Battery 18650 Cell Test Results

Discussion in 'Model S: Battery & Charging' started by kennybobby, Mar 2, 2015.

  1. kennybobby

    kennybobby Member

    Sep 14, 2014
    Heart o' Dixie
    A couple of fellows over at the DIY Electric Car site have purchased and dismantled a Tesla pack to open a module to get an individual cell for testing.

    One measured 2.9 A-Hr capacity, which is right in line with some of the Panasonic datasheets found online.

    The other fellow measure 3.02 A-Hr using a 10A discharge rate down to 2.55V and a 100mA cutoff current while charging.

    They were reported to be from a 'rev B' pack.

    tesla model S module for sale - Page 2 - DIY Electric Car Forums
  2. techmaven

    techmaven Active Member

    Feb 27, 2013
    Very interesting. They had a much higher cut charge and only tested to 2.55V instead of 2.5V and was still able to get 3 amp-hours. From the follow up postings, these cells came from a Rev B pack with 3200 miles, but they sat at 0 miles for 2-3 months. Still had 3.3 volts in the cells, that's terrific.

    The NCR 18650A datasheet shows 3.1Ah at 2C, but with a 59mA cut-off at 25 degrees C
    The NCR 18650B datasheet shows 3.3Ah at 2C, but with a 65mA cut-off at 25 degrees C

    I certainly can't tell if it is closer to a NCR18650A or a NCR18650B.
  3. okashira

    okashira Member

    Nov 16, 2006
    #3 okashira, Mar 2, 2015
    Last edited: Mar 2, 2015
    I tested the cells. They are neither NCR18650A nor NCR18650B. They are NCR18650BE.
    I was going to post a thread once I have a more proper test done. This was quick and dirty. We are still working on cell removal.
    Ignore the 2.9Ah measurement. That was done on a really old, cheap hobby charger that cut at 3V and is horribly inaccurate...

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