Short trip tips?

Discussion in 'Gen 2 Prius Fuel Economy' started by pasadena_commut, May 2, 2019.

  1. pasadena_commut

    pasadena_commut New Member

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    The dealer put on new tires (Ecopias) and changed all the fluids. The oil still has that clear/new appearance.

    I was not trying to hypermile but I did notice something peculiar the other day. There is about 3/4 or 1 mile (never measured it carefully) downhill stretch on the way home. A couple of days ago I finally figured out the pedal pressure to make the display arrows go black and I hit all the lights right for once. SOC fell two bars over that distance and maybe 4 minutes. The car was on, the radio was on, but the headlights weren't. So not a huge power draw, I would think. I would have thought that a healthy 12V alone could have supplied that current, but I think this one is very much on the way out. That much SOC charge drop for so little load does not give me a warm and fuzzy feeling about the big battery.

    Regarding the 12V battery, using the "signal check method" in ACC-ON first thing in the morning (car sat overnight, ~14 hours) shows a voltage of just 11.1V. Seems mighty low for 12V lead acid battery!
     
  2. bisco

    bisco cookie crumbler

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    no a/c on? yes, you probably should replace the 12v
     
  3. Mendel Leisk

    Mendel Leisk Sidewalk Supervisor

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    Pop the hood at night, then in the morning: check battery at jump point, with a digital multimeter. Better yet, something like Solar BA5, an electronic load tester. Post your findings.
     
  4. pasadena_commut

    pasadena_commut New Member

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    12.39-12.40V after drive home
    12.24V 17h later

    Car completely off both times. Obviously this battery is on its way out. Depending on the table referenced that last measurement is about 50% SOC. A healthy car would be close to 100%.

    The dealer says that if I bring it in they will load test it and if it doesn't pass, replace it. (Because the million point check list said the charging system was within spec.) Load test instructions usually say that the battery should be at at least 75% before running it, which it might be, barely, for about 2 minutes after the car gets to their location, otherwise, too low to test.

    One of the two tabs that holds the fuse box lid down is flopping around, it mostly peeled off the side of the box and is now attached only by a narrow sort of hinge at the bottom. The lid is really only held in place by the latch at the bottom and the other tab, the broken one isn't doing squat. Anybody ever fixed one of these tabs? Superglue, epoxy, or something else?
     
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  5. pasadena_commut

    pasadena_commut New Member

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    2007 Prius
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    12V battery replaced this morning by dealer (for free). On first startup signal check showed 12.5 V and in ACC-ON it only went down to 12.2 V. Much better! Probably won't make a bit of difference in the mpg department, but will post an update if it does.

    To balance our "Carma" my wife's late 90's Accord lit its CEL the very same morning, while I was driving back from the dealer. (It was an evap system code - reseated the gas cap, cleared the CEL, and it stayed out on the next restart.)
     
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