Driving with a dead HV battery

Discussion in 'Gen 2 Prius Technical Discussion' started by ryguy, Jul 27, 2021.

  1. ryguy

    ryguy New Member

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    I have a dead hybrid battery in a 2006 Prius. Exclamation point, ran code, dead. It's still running ok though, which brings me to my question... now, I have a first generation honda insight and it can run all day with a dead hybrid battery(read: forever) as long as you bypass the hybrid system(if you don't do the bypass it never charges the 12v and eventually dies)... so I'm wondering if the Prius behaves similarly? Or if you even need to do anything to it to make it run without the HV battery(and still charge the 12v), because it's currently running fine, albeit sluggish. What is the longest you've been able to run your Prius with a 'dead' hybrid battery?
     
  2. bisco

    bisco cookie crumbler

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    it's not actually dead. if it were, the engine wouldn't start. it probably has some out of parameter modules.

    you can drive it until you can't. we can't tell you how long that will be.

    with a prius, 12v starts the computers and relays, hybrid battery starts the engine through the tranny, and keeps the 12v charged through the inverter, engine recharges the battery, along with regen.
     
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  3. PriusCamper

    PriusCamper Senior Member

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    Honda will let you drive for a long time with a bad hybrid battery pack... Toyota on the other hand will shut down the hybrid system and throw you into limp mode at the first sign of a problem and you'll be lucky to get home if you have any hill climbing...

    So with Prius, you need to clear the error codes and hope you can drive a little further before error codes come back. Fastest way to do that is to use Dr. Prius App via and OBD2 reader. Here's buyer's guide: Hybrid battery diagnostic and repair tool for Toyota and Lexus
     
  4. fotomoto

    fotomoto Senior Member

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    In the HSD design, ONLY the hybrid battery crank starts the ICE so once it falls below a minimum state of charge you’ll have a very expensive and heavy brick. Unlike the Honda design, there is no 12v starter motor to fall back on. You must fix the HV battery.

    GOOD LUCK!
     
  5. ryguy

    ryguy New Member

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    Thanks for your responses guys, really appreciate it. Looks like I need to save up, because I know I'd end up killing myself doing the work myself. lol
     
  6. Bob Holliston

    Bob Holliston Junior Member

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    I got the Triangle of Death in my 07. First, I enrolled in YouTube University, then pulled the battery and found the bad cell. I bought a used cell on eBay ($19.95, free shipping.) Replaced the cell.... fixed. That was over a year ago. So far.... so good.
     
  7. mr_guy_mann

    mr_guy_mann Active Member

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    Wow- congrats! I think that your post is only the third one I have seen (in the past year+) where someone "just replaced a bad module" and it worked- at all.
    Much more common is for a module to be replaced then the ecu pops another code for a different module because the "new" one has a higher capacity and now the "next weakest" module has too much voltage difference.
    So they replace that module, then the next, and so on in a game known as "whack a mole". Might be a few weeks, or days, or immediately. If it worked for you? - might want to go buy a lottery ticket.

    Posted via the PriusChat mobile app.
     
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  8. dslomer64

    dslomer64 Member

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    I assume "limp mode"--in which you may be "lucky to get home if you have any hill climbing"--can be transient, because I've been driving my '06--which apparently has decent12-volt but near-dead hybrid battery--for maybe 500 miles over the past 18 months, and usually it runs acceptably--dare I say "well"? Oh, sure every conceivable warning light has been on for those 18 months, but for good reason based on how hybrid system works, I've been told.

    On occasion--let's say once a month--going up ANY hill is threatening to the nervous system, but generally, day to day, I'm okay with it. There are also times when--without a tachometer to confirm it--it sure sounds like it's over-revving to no avail. I've found recently that pulling over, shutting down for 10 seconds, and going again seems to cure the over-revving. Usually this occurs when I'm driving it over 50 mph, so I stay off interstates as much as possible. I swear, city driving seems almost normal.

    We try to only drive it on short runs to grocery, hardware store, nearby doctors. This isn't nerve-wracking unless there's a hill going home (like, always), and even then it climbs the hills okay the vast majority of the time. If it were an everyday occurrence, I'd take action.

    I've driven it a few times on 50-mile round-trips with no ill effects at all. I'm going on a 40-miler in a few minutes to a doctor. Wife needed the '17 for an 80-mile round trip. And I'll have to do interstate at about 50-55 but 60 is tempting. Speed limit is 60-65.

    We don't really need two cars. I did Lyft once when '06 12-volt was dead. Wasn't bad. Better price than Uber. Rumor has it that any newer car is gonna have a steeper price tag than is acceptable, so I'm again leaning to replacing the hybrid battery with a refurbished one from Green Bean Battery for $1499 or thereabouts. Last year, it was guaranteed for life (of company!). This year, 3 years with option to make it lifetime. Haven't priced that.

    Not saying this is all proper treatment of the car nor that it is advisable for driver and rare passenger. Just my own anecdotal anecdote. For what it's worth. I've never considered myself lucky, except for twice when loss of limb(s) was a distinct possibility. Just a finger was damaged and its nail made freaky by one instance of poor judgement. Another time, I just got two fingers' distal joints smashed (fully recovered) instead of two hands, forearms, or worse.

    Dave Slomer
     
    #8 dslomer64, Oct 13, 2021
    Last edited: Oct 13, 2021
  9. ChapmanF

    ChapmanF Senior Member

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    The practice of continuing to drive on a failing battery for long enough can eventually end in a loud noise and bad smells from the back of the car, and a tow. It just isn't easy to say how long will be "long enough" for any one person's car.
     
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  10. dslomer64

    dslomer64 Member

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    Guess I'll give Green Bean a call after I get an OBD2 scan to see what else might be bad. The car's cosmetic side is pretty bad. Several dings, a couple dongs (major dings), rough interior. Before used car prices skyrocketed (as I've heard/read), I'd considered donating it to local Public Radio station or Goodwill, which I did with ye olde '95 Corolla. Now, maybe new hybrid battery.

    But I don't sense that the car is in limp mode since it runs normally so often for so long. Then again, I don't exactly know how to tell if I'm limping or not.
     
  11. Another

    Another Member

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    Call Greentec too and get a quote for new cell battery pack rather than GreenBean old cell pack.
     
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  12. Galane

    Galane Junior Member

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    Here's another option for $1600. New Prius Battery Kit (GEN2, 2004-2009) - New Prius Batteries LLC

    Higher capacity than OEM. The cells are new, it comes with a new wiring harness so all the internal connections will be fresh, and it's higher capacity than OEM so it'll give electric boost for longer. The round cells also make for much better airflow through the battery for better cooling.

    That kit does involve taking the old battery apart to replace the cells and wiring with the new parts, so one must take the precautions required for working with high voltage DC. The people showing how to take these apart on YouTube mostly use insulated tools and HV gloves, but it looks like being *very careful* and paying attention should work as well, especially if tool shafts and sockets have shrink tube applied.

    One of those videos shows how many of the battery issues can simply be oxidation on the busbars and nuts that join the cells. Some people buy kits of new parts to replace them but some light sanding to clean the originals works just as well. Before sinking $$$$$ into any refurbished or new battery, I'd try cleaning the busbars. Would be a much easier job to do that if the battery didn't have to come out to get the top cover off.

    This guy shows how to remove and replace a 2nd gen battery in 15 minutes.
     
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  13. Another

    Another Member

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    You’d get a lot more $ for the old Prius by selling it for parts or to someone who wants to fix it than donating it. The tax laws have changed and it’s unlikely you’d get any financial benefit from donating it to goodwill or other charity.
     
  14. dslomer64

    dslomer64 Member

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    Good point. I think it's something like this: if you do NOT itemize, you CAN take a deduction for whatever, BUT the max is $300. I hadn't thought about that when contemplating donation.
     
  15. dslomer64

    dslomer64 Member

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    Yeah, but problem is I'm 75 with typical aches and pains, some worse that others. Back pain mostly: sciatica. :eek:

    If I were 35, maybe even 45, I'd definitely have thought about doing it myself until seeing that video. Fifteen minutes for him, fifteen days for me back then.
     
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