6 bars drops to 1 then normal for the remainder of the day. HV battery on the way out?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Priusyipee, May 6, 2018.

  1. Priusyipee

    Priusyipee Active Member

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    Let's cut to the chase: 2008 Prius with 180,000 miles give or take. Upon start up, HV battery showing 75% charge (6 bars) but discharges as I am driving. The indicator drops as low as 1 purple bar before beginning to charge again. Once the HV battery is back up to 6 or 7 bars, it stays the same for the remainder of the day. The next morning, the same situation and so on. Temperatures during the day have been in the high 60s low 70s and dip to the 40s at night. This happened a few times last fall but resolved itself once the cold weather set in. Now that the weather is warming up, this problem has returned. No codes or lights on dash.

    What I need to know is this: Does the HV battery indicator EVER lose all the bars (empty)? Does the fan ALWAYS come on in the rear prior to failure (mine has not come on yet)? I realize that the battery can decide to die today or last another year with the same symptoms.

    I would like to hear from any owners who experienced similar situations. Should I price shop the local dealerships for a battery? What have YOU done to resolve this problem? What is Toyota installing in the Gen 2s?
     
  2. bisco

    bisco cookie crumbler

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    1) no

    2) the fan can be on anytime even with a new battery. but sometimes it will come on at high speed when the battery is on the way out, not always.

    it does sound bad, have you cleaned the cooling fan?
     
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  3. fotomoto

    fotomoto Senior Member

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    Yup, it's a sign you have one or more modules starting to weaken and will eventually fail. No, it never goes zero bars.

    See the link in my signature to see what I did when this happened.

    GOOD LUCK!
     
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  4. Priusyipee

    Priusyipee Active Member

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    Haven't cleaned the cooling fan since I bought the car in March 2013. No pets and no kids in the car, windows rarely opened. Previous owner did have pets but the car was not trashed. The only difference between now and a few weeks ago (when we were still getting snow) is that I no longer allow the car to warm up with the heater and defroster "on" before leaving in the morning. I may try allowing a warm up period to see if there are any changes. There is no decrease in mileage that I can see. Is there a correlation between a/c output and a failing HV battery? I was annoyed on one particularly warm day last week when the temperature got up to 82 degrees and it seemed that the a/c was barely putting out cold air. The fan was on high but acted as if it was on a low setting...
     
  5. Priusyipee

    Priusyipee Active Member

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    I see that after the rebuild, you went with a new Toyota battery in July 2017. Did you do the install or did you have the dealership install it? If I had the time, I would mess with the battery myself but right now my free time is limited due to my house renovation. I do have another vehicle to keep me going but it guzzles much more gas than the '08! I have a 2005 (original owner) that has 323,000+ miles on the original hybrid battery with no maintenance at all over the years. Unfortunately, not all of these batteries last as long. Luck of the draw, I guess.
     
  6. fotomoto

    fotomoto Senior Member

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    Actually another option available to me: texashybridbatteries.com My local dealers pricing was so prohibitive that I drove across most of Texas to get it from Matt; he also offers a 4 yr warranty but honestly that wasn't a decision maker for me as I'm quite confident in the quality of the OEM battery. Moral to the story: shop around.

    GOOD LUCK!
     
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  7. Priusyipee

    Priusyipee Active Member

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    Ok. I have read more than enough threads on the Gen 2s. Some have said that allowing the car to warm up before initial take off in the morning should help. I experimented and did this. The HV battery responds as it should. No more purple bars and stays between 4 and 6 most of the time. Normal charge and discharge and is getting an average of 52.2 miles a gallon since my last fill up. Is this only a temporary solution?
     
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  8. bisco

    bisco cookie crumbler

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    no idea, never heard that before. maybe because it uses more battery when the engine is cold?
     
  9. Priusyipee

    Priusyipee Active Member

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    That's exactly what I have read. Tried it now for the past few days and the problem has disappeared for now. I'd like to match the reliability that we're getting with our '05 which has over 324,000 miles on the original engine, transmission, and HV battery!
     
  10. rwhyde

    rwhyde Junior Member

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    WOW! you have been getting some impressive life from your batteries and that is great mileage for a Gen 2. If your battery was going out your mileage would drop 10-15% or more from that number. Also, the engine with then rarely if ever turn off at stops. It is noticeably different performance not just bars visible on the monitor. Keep us posted on what you see over time.
     
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  11. dolj

    dolj Senior Member

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    Yes, but it could be temporary for quite some years. Uart was a big advocate of this technique and drove his for many years before his HV battery finally gave up. You maybe able to extend the life somewhat using the HA grid charger/discharger system to recondition the HV battery. Edthefox5 found this to be the case.

    As you probably already know, in stage 1 of warm up, the Prius almost wholly uses the the HV battery for propulsion while in that first 50 seconds of warm up before it advances to stage 2. You can force it to stage 2 by flooring the accelerator, if you need power now, but there is a jerky delay for a fraction of a second while it reconfigures. However, I would not advocate doing this on a regular basis.
    Unfortunately, it sounds like you have two very different HV batteries and until the 08's HV battery is replaced with a new one, I don't think you will get better from it.

    Who knows why the two batteries are so disparate, maybe the previous owner(s) thrashed it real hard thinking it was a racing car in its early days?
     
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