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Solar Charging Model S Battery Pack

Discussion in 'Energy, Environment, and Policy' started by jrickard, Sep 16, 2017.

  1. jrickard

    jrickard Member

    Joined:
    Sep 4, 2009
    Messages:
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    Location:
    Cape Girardeau Missouri
    I am working on a system to incorporate a battery pack from a Tesla Model S into a Solar system for the home. This uses the entire pack from salvage as is.

    Yesterday, I discharged the pack down to about 1.4% state of charge using a 20kW inverter to the point where the internal BMS master board disconnected the internal contactors.

    And subsequently I charged it to about 92% SOC using 40 Panasonic HIT panels in our test array. The controller software allows me to log voltage, amp hours and state of charge each minute so I made a graph showing the charge curve.

    It's kind of interesting, so I thought I would share it here.

    I was surprised that there really isn't anything left below about 320v on these packs. But at 226Ah used to 1.4% I think we are pretty close with the 230Ah estimate for pack capacity.

    The jaggies are of course caused by passing clouds decreasing the power output of the array.
     

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  2. miimura

    miimura Active Member

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    Aug 21, 2013
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    Los Altos, CA
    What are the units on the X axis of the chart? Minutes? SOC%?? 91 minutes seems way too fast to charge a 85kWh pack from 40 solar panels.
     
  3. ucmndd

    ucmndd Member

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    Location:
    California
    Appears to be state of charge.
     
  4. nwdiver

    nwdiver Active Member

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    What are you using to charge it? DC-DC or DC-AC-DC?
     
  5. SageBrush

    SageBrush 2018: Drain the Sewer

    Joined:
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    #5 SageBrush, Sep 17, 2017
    Last edited: Sep 17, 2017
    How is this pack thermally controlled ?
    It pains me to see your graph labeled 85 kW
     

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