Interesting increases in battery distance

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by sprintermike, Mar 20, 2020.

  1. sprintermike

    sprintermike Junior Member

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    Just made some interesting observations and wanted to see what others had observed or experienced.
    I purchased a used 2012 PIP last year at this time. It appeared to me that the vehicle had not been plugged in at all or very little during it's previous use. When I first charged it up I got 13.5 miles electric range (in mild weather with no A/C use). This was early March 2019. The time to reach full charge from empty was about 3 hours.
    During the year, the range on a full charge gradually went down, sometimes in small bits, sometimes in large chunks, though always under the same conditions (mild temps, full charge, no A/C). As of early march 2020 it was down to 8.5 miles. I began to measure the the miles traveled and found this was very accurate to the miles lost while driving in EV mode. My assumption was that the EV miles was being adjusted based on my driving style/conditions. I had read somewhere the PIP would do this. I also noted that it took only 90 minutes to reach full charge from empty.
    I took the vehicle in for recall work (fuse and airbag shields). Due to travel, I had to leave it for 10 days. When I cam back, the 12 volt battery was dead and needed to be replaced. After replacing the battery, the new EV miles on a full charge are now 13.8! I assumed it was because the computer "lost" my driving data and was just giving me a best case scenario, however, when driving it today I found that it was really and truly going SIGNIFICANTLY farther in EV mode than it had just two weeks ago.
    Is it possible that a low 12 volt battery can result in bad traction battery estimates from the charge control module? or that the stored data will limit the amount of charge loaded in or taken out of the trac battery? In some way, replacement of the 12 volt battery has resulted in real and significant increases in EV mode driving for me.
    thoughts?
     
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  2. Deoc

    Deoc Member

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    The 12v battery is constantly being charged by the large battery, usually when the 12v battery starts to go bad the system need to charge the battery more often to keep the voltage, so you end up getting less miles.
     
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  3. bisco

    bisco cookie crumbler

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    how long does it take to charge now?
     
  4. jerrymildred

    jerrymildred Senior Member

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    Not a bad estimate of EV miles. Just plain reduction in EV miles. The traction battery is propelling the car and maintaining the 12V charge. If the 12V isn't charging, the current going into it to charge it is largely wasted.

    However, a 50% reduction in traction battery charging time implies a massive reduction in its capacity. I would not expect that to come back all by itself just with a new 12V, so there's something mysterious going on there.

    Then again, I just remembered something. I have been told by a friend who works on Prii for a living that disconnecting the 12V will often sort of reset the battery management system and can bring increased range and (I assume) increased capacity to an older PiP. I tried that once on my PiP, but it made no change at all. Then again, I was still getting 12-14 miles anyway.
     
  5. bisco

    bisco cookie crumbler

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  6. sprintermike

    sprintermike Junior Member

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    The battery now takes approximate 150 minutes to reach full charge from fully depleted. A significant increase from just 2 weeks ago.

    My impression is that somehow the charge controller is allowing more total “charge” in (or out) per cycle. Some of these terms may not be correct because I am not an engineer, but I think you get the idea.

    I certainly don’t have a good explanation on how I got down to 8.5 EV miles and a 90 minute recharge time (indicating either only partial discharge or subtotal charging), but whatever the charge control module did has been undone and I am back to “baseline.”

    this may sound ridiculous, but I’m wondering if a build up in static charge can interfere with battery estimates, leading the control module to act funny. Or a build up of excess data consist the algorithm in the charge control module to get glitchy?

    either way, happy to be back to a longer ev drive! Interested in any other thoughts or observations.
     
  7. QuantumFireball

    QuantumFireball Active Member

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    90 minutes would be normal for charging from a 220-240V input. Even with mine and its similarly low range estimation (was around 8.5 miles a few weeks ago, but going up again) still takes that long (mains is 230V here).
     
  8. bisco

    bisco cookie crumbler

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    yeah, 90 minutes at 120v wasn't filling his battery. sounds like the computer had a 'windows' moment, and the reset did what it does to all computers
     
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