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Strange battery or electrical issues on 2006

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by sfatula, Jan 20, 2013.

  1. sfatula

    sfatula Junior Member

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    I've been noticing a variety of issues with my 2006 Prius lately. All of these I believe are different behavior than has been seen in all years previous. Differences:

    • Gas mileage has dropped by 5-10 MPG, worst is city driving. My habits have not changed
    • A few times lately, I have stopped at a light admittedly soon after starting the card for the first time in a day. At the light, the engine is running as it does while warming up, and then, eventually, starts to go off, like it always did once warm. However, just before the engines stops all the way, it starts back up, rough. < 1 second later, it begins to stop again, and so on.
    • The other day, after being well warmed up, had stopped at a light. The engine shut off, as it's supposed to do. 10 seconds later, I noticed it started back up, which was odd. So, I looked at the display and the battery level had one bar left, so, battery discharged (I believe it should not have been). So, say it was discharged. Engine should be on. I started up after the light turned green, and, I watched the display. Within 5 seconds, it had gone from the discharged state all the way to full blue bars. I've never seen this happen.
    • After running for the first time in a day, more often than not, even if the battery was green level the night before, I start out. Within a few hundred feet, the battery level starts to drop, and all the blue goes away on the charge level. This one I am not positive, but, I don't recall this happening in the past. SOme days, this does not happen, it does discharge a blue bar or two, but that's it. Which I believe it what it used to do.
    Any ideas what might be a common thread here?
     
    #1 sfatula, Jan 20, 2013
  2. Britprius

    Britprius Senior Member

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    This is a common symptom of a failing high voltage (traction) battery I'm afraid.

    John (Britprius)
     
    #2 Britprius, Jan 20, 2013
  3. Britprius

    Britprius Senior Member

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    It is very likely that the car will shortly give out fault codes. You do not give any indication of country, and if in the US state you live in, also the mileage of the car these are all important to your plight.

    John (Britprius)
     
    #3 Britprius, Jan 20, 2013
  4. sfatula

    sfatula Junior Member

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    Well, it turns out lots of failure codes showed up on the dash the other day (as you said) driving back from a small trip, car responded really badly and was hard to get going, acceleration was abysmal, it would take 10 seconds to get up to 20 MPH. None of the codes were the so called red codes which said stop immediately. This is in Texas. Miles is 77,000. So, the failure codes indicated a fault in the 12v battery, as well as the hybrid battery pack. They initially just replaced the 12v saying it was almost certain the codes would go away for the hybrid pack, but, they did not. So, they replaced the hybrid pack. Under warranty. That dealer claims this was the only one they have ever replaced on any Prius model. Does that sound believable? They've been in business for longer than the Prius has been out.

    I am going to pick it up shortly. I suppose if that is ever going to break, this is a good time closer to the end of warranty period.
     
    #4 sfatula, Jan 24, 2013
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Well, I suppose that would depend upon how many Prius that dealer has in its service area... I would expect that the dealer would have the opportunity to replace traction batteries under warranty for a single-digit percentage of the cars in its area.
     
    #5 Patrick Wong, Jan 24, 2013
  6. V8Cobrakid

    V8Cobrakid Green Handyman

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    it's nice to see they replaced items under warranty.

    i feel we can't really be of too much use unless you find the codes and supply them here for opinions/recommendations.

    low power and poor charging can also be other items... like the 12v inverter that charges the 12v... or a bad ignition coil (the car would ride rough though)...
     
    #6 V8Cobrakid, Jan 24, 2013
  7. nh7o

    nh7o Off grid since 1980

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    With regards to the HV battery going out so soon, this is another case of a car in a hot climate with shortened battery life. The HV battery can suffer from being over heated, and the car being parked in the sun. Keep the car cool, park in the shade, use window reflectors, and don't park the car on a hot day with the battery indicator showing green bars. Let the A/C run for a bit and bring the charge level down some before shutting down.
     
    #7 nh7o, Jan 25, 2013
  8. V8Cobrakid

    V8Cobrakid Green Handyman

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    wouldn't putting a load on the battery before shutting down cause more heat?

    when i was working in extremely hot climates, i would stop the a/c and major electrical draws before i get to my destination. when i did arrive, i would let the car naturally shut down. Otherwise, i've seen that putting any sort of heavy load (regen down a big hill, heavy a/c usage, charging up) would make the battery suffer a bit, and sometimes the battery level wouldn't be the same as i left the car. I've assumed this is because of the internal resistance giving a false reading due to heat.

    So... from my experience, i've leaned to let the charges balance out a bit and let the car naturally turn the ICE off before turning the car off.
     
    #8 V8Cobrakid, Jan 25, 2013
  9. nh7o

    nh7o Off grid since 1980

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    No. The info comes from PC member seilerts, and he has a number of posts in the past about the HV battery and heat. There is an exothemic reaction that takes place in the HV battery when it is full. That means it continues to get warmer for a while even after the charge current has gone to zero. The temperature rise after shutting down the car in a hot location, with the sun beating down, can cause electrolyte venting. Lowering the charge to a moderate level is a way to mitigate that exothermic effect, and using the A/C to lower the car temp runs that cooler air through the HV ventilation fan, which also helps.

    This may not be relevant in a flat place like Texas, where green bars are probably not seen much, but it's worth noting.
     
    #9 nh7o, Jan 25, 2013
  10. sfatula

    sfatula Junior Member

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    Guess you've never been to South or West Texas! In the big Bend I got all the way to the top on the power display, easily, long before I made it down the mountain. It's the only mountains I have ever been in where it's still above 90 at the top, that was weird. Actually, I get green bars fairly often just by pulse and glide. Harder in summer since the AC is running so hard. Very common the rest of the year. So, it sounds like not so great to have green bars when parking outside in heat.

    I probably do not use window protectors as much as I should, they are a slight hassle but if it means longer battery life.... I DO try and park in the shade where available, but as you might imagine, shady spots are picked up first by everyone else.

    I have another way to lower the charge, I have the mod from I don't recall where.... Where I can hold a handle in near the steering wheel (now I don't recall what handle, turn signal I think, it's just automatic for me) and force all electric mode. So, would be trivial to all electric my way in to my destination to get out of the green. Still, in summer, even when I get to one green bar, it doesn't last long, doubtful I ever park in green, just too much ac going.
     
    #10 sfatula, Jan 26, 2013
  11. V8Cobrakid

    V8Cobrakid Green Handyman

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    interesting about the exothermic reaction....

    in my personal opinion... i am aware how the system cools, but i've always felt that even with the A/C on, not much air vents through the battery. the intake for the system (fresh air intake) is only 1 inch by 1 inch, and can't really provide THAT much air pull from the outside. I get how lowering the SOC still helps either way.

    it kinda makes me wish there was an option to manually turn on the cooling fan for the pack...
     
    #11 V8Cobrakid, Jan 26, 2013
  12. V8Cobrakid

    V8Cobrakid Green Handyman

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    wasn't the mod from ecoastaltech (however it's spelt?)

    i prefer the instant doorbell button by simply wiring up into the harness behind the glove box.... i like my steering column to keep all of it's original functions...
     
    #12 V8Cobrakid, Jan 26, 2013
  13. nh7o

    nh7o Off grid since 1980

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    I agree. There was some talk about that, using CAN bus commands to turn up the fan speed. I don't know if it was ever done. The think the fan can be turned on and off using Techstream, so it should be possible.
     
    #13 nh7o, Jan 26, 2013
  14. nh7o

    nh7o Off grid since 1980

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    No, I haven't. So I stand corrected. PC used seilerts is in New Mexico, so probably similar situations. He has seen the cooked battery phenomenon there.
     
    #14 nh7o, Jan 26, 2013
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