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Newbie with a newbie question

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  • johnnydwa
    I am a newbie 96 force owner just having picked it up from E-bay. I have one question about instrumentation. My Force has a State of Charge indicator
    Message 1 of 2 , Jun 9, 2009
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      I am a newbie 96 force owner just having picked it up from E-bay. I have one question about instrumentation. My Force has a State of Charge indicator (percent 0-100%) and three vertical (green-yellow-red) lights. My guess is that they all relate to state of charge, but my question is that after a full charge the meter reads 50% and after a short distance (~10 ah) this drops to 10%. While this is concerning, I have managed to keep driving well past 30 ah without every hitting the dreaded crawl home.

      Two theories:

      1. the meter's calibration is off and I should be starting at 100% (no matter the condition of the battery pack) - any thoughts on how to change?

      2. the meter is correct and my pack is shot, but somehow I am pushing the pack into deep DOD. But this doesn't really make intuitive sense. Can someone explain?

      Does anyone else have this type of instrumentation or is it a TVA add-on?

      jd
    • ldr214
      I don t recall any mention of that specific meter being a production add on. But the boys and girls at Solectria might have done it. I m guessing it is after
      Message 2 of 2 , Jun 9, 2009
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        I don't recall any mention of that specific meter being a production add on. But the boys and girls at Solectria might have done it. I'm guessing it is "after market."

        If it is after market how it is wired into the pack is a total unknown so giving advise is risky.

        My guess and again it is a guess is that it is just using voltage and not AHs to determine SOC. If it is still functioning you likely need to depower it and then repower it when the pack is at 100% SOC. As an add on it could be just monitoring one battery or the pack. Will leave it to you to figure out the wiring unless someone else can provide the info.

        Meters that determine SOC based upon voltage are always just making a crude "guess". Under load voltage sags and at rest it climbs. Regen also makes it rise. Anyhow it takes some pretty fancy processor and programing magic to keep track of all of that just using voltage in a EV and end up with the real SOC. In a stationary battery situation like a back-up power supply or off grid house with a pretty constant load voltage works pretty well. Many of these meter are really designed for that type of application.

        The AH meter as installed at the factory is a pretty reliable indicator. If your not already familiar with Peukert I suggest a bit of reading on Pba batteries. Basicially the harder you use the pack the less power it has in it. The AH meter is going to register the current but you'll reach a lower real SOC sooner. The info on the visor if it is still there is pretty good. Try not to drive over 25 AHs and you'll stay below 50% SOC.

        Your pack certainly has more than 10%.

        Mike R
        97 force

        --- In solectria_ev@yahoogroups.com, "johnnydwa" <johnnydwa@...> wrote:
        >
        > I am a newbie 96 force owner just having picked it up from E-bay. I have one question about instrumentation. My Force has a State of Charge indicator (percent 0-100%) and three vertical (green-yellow-red) lights. My guess is that they all relate to state of charge, but my question is that after a full charge the meter reads 50% and after a short distance (~10 ah) this drops to 10%. While this is concerning, I have managed to keep driving well past 30 ah without every hitting the dreaded crawl home.
        >
        > Two theories:
        >
        > 1. the meter's calibration is off and I should be starting at 100% (no matter the condition of the battery pack) - any thoughts on how to change?
        >
        > 2. the meter is correct and my pack is shot, but somehow I am pushing the pack into deep DOD. But this doesn't really make intuitive sense. Can someone explain?
        >
        > Does anyone else have this type of instrumentation or is it a TVA add-on?
        >
        > jd
        >
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