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100% Charge Taper / balancing graphic

Discussion in 'Model S: Battery & Charging' started by Zextraterrestrial, Feb 5, 2014.

  1. Zextraterrestrial

    Joined:
    Mar 11, 2010
    Messages:
    3,900
    Location:
    Humboldt/Los Altos
    Here are 3 100% charges that I VT logged. There was one more charge done on 2/1 that wasn't logged
    You can see how the final time remaining can vary by quite a bit. Scale of each is the same and I lined up the time of completion of each charge
    .. heater was on in the first and second for a bit in case you haven't seen the amp spike like that before

    Capture.JPG
    Capture1.JPG
    Capture2.JPG

    note - the last one is pretty and the taper curve is much tighter + my rated range at 100% was 5 mi higher than the first charge.

    - in each charge it sat at 99% for about an hour, longer on the first

    - Amperage taper began
    #1 - >100 min before completion
    #2 - ~60 min before completion
    #3 - 50min before completion
    ( with this the Voltage goes up a tiny bit)

    - check out the Rate of Charge Vs. the Amperage, and when each decreases
    first charge, the Mph decreased well blow 95% SOC
    second was very near 95%
    and the last was already at 99% SOC - but the time spent at ~ 20Mph charge for 40 minutes only put ~1 mile on the rated mi total

    interesting, no?

    I also noted that charging from 50% to 60% took ~ 75% of the time as each other 10% jump (except the last 10%)
     
  2. NielsChr

    NielsChr Member

    Joined:
    Oct 18, 2011
    Messages:
    265
    Location:
    Denmark
    re balance circurit

    rebalance circurit.png
    a re-balance curcurit I came up with. the actual values for dump resistor and zener are exaples.
    the FET controls wheter or not to re-balance - your dont need to monitor each cell and they will all eventual be charged at 3,7 volt.

    under normal use/charge there is aapplyed a charge to the FET wich then shorten the resistor (dump load), if re-balance is needed the charge to the FET is removed and a over voltage is applyed to the bank. e.g. 12-13 volt. once a cell reach 3.7 volt the current will automatically flow into the ressistor and zener (you will need a cooling system) only cells under 3.7 volts are then charged (yellow in the circurit)
    .
    After a while all cells will be equalized at 3,7 volt.
     
  3. Muzzman1

    Muzzman1 Member

    Joined:
    Feb 8, 2014
    Messages:
    389
    Location:
    Los Angeles
    I have a similar graph to add to the equation (the 1st and only time I've Range Charged as of yet)
    Screen Shot 2014-06-07 at 3.57.49 PM.png
     

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