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Overheated battery

Discussion in 'Gen 2 Prius Main Forum' started by PRPrius, Jun 18, 2011.

  1. PRPrius

    PRPrius Active Member

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    Today the outside temperature was 105 degrees at work, the car was park in the shade and two hours had passed since the last time it was driven. I started the car, and turned on the A/C; I always wait for the engine to start and then stop again. (Traction Battery SOC was green, it was almost full!) I engaged reverse and the gas engine kicked in immediately; the batteries cooling fan switch to its highest speed. I backed out of the parking space and place the car in drive (engine was still on). As soon as I step on the gas, the car felt incredibly sluggish, as if only the gas engine was trying to get the car moving. The moment I passed two miles per hours, the engine switch into a high rpm mode; it stayed in high rpm for as long as I stayed in drive. I pulled to the side and place the car in park, the rpm drop somewhat and I waited while the batteries cooled down. I waited five minutes and the car was still in cool down mode. I went ahead and started driving, I did notice that the car was once again using the traction battery to provide assistance to the gas engine. It took another 15 minutes before the battery's fan switched to a lower speed.

    I had never experience this particular mode; it was a very interesting experience. Considering the weather is going to be just as hot tomorrow, I am crossing my fingers I don't encounter the same issue.
     
  2. bisco

    bisco cookie crumbler

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    how many miles on her?
     
  3. edthefox5

    edthefox5 Senior Member

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    Can I assume interior temps were extremely high which is why t battery fan came on?

    3 things:

    Need a real good tint job. With the angle of the front windshield the cabin will get incredibly hot.

    Need to buy a windshield shade here at Priuschatshop. Had mine for
    4 years now and still good. Very thick & Fits very tight.

    Crack the front windows a little. Buy rain guards on eBay for $30. They work really good. You can crack the window 1/4 inch and rain will not get in.

    I live in Tampa and its regularly that hot but with the sytem above I have never ever heard the traction battery fan come. Not once.
     
  4. PRPrius

    PRPrius Active Member

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    Right now it has 88,000 miles
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Check the fan for dust build up?
     
  6. M8s

    M8s Retired and Lovin' It

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    All good advice.

    Living in AZ, we hear a lot about cars getting up to 140 degrees inside after just a few minutes in the sun on a 100 degree day. You have to do what you can to keep interior temperatures down. We use a windshield sun shade and window tint and it works like a charm.
     
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  7. andyprius

    andyprius Senior Member

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    What temperature did the HV Bat get to, that you KNEW it was overheating ????? I think you made an nice person umption! The engine runs to move the car and charge the HV, The HV powers the AC. The AC cools you and the HV Battery area. I contend that everything was working normally and you should not worry about it. The computers take care of everything. I was in Las Vegas the other day and decided to eat a sandwich in the car, temperature 109 degrees. Put car in ready, with AC on and Prius performed flawlessly. I never touched the go-pedal. Ran no other accessories. The duty cycle for about the 20 min I sat there was about 5 to 1. That is engine on and charging to upper blue state for about one minute. AND then engine off for about 5 minutes to a HV Bat PINK state. With AC set to a comfortable temp 72 to 78. I later increased the temp as the car got more comfortable.
    If you hear the HV fan increase in speed OR hear the engine increase in RPM then everything is totally normal. That is what the car is designed to do!:cheer2::focus:
     
  8. PRPrius

    PRPrius Active Member

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    The reason why I could tell the battery's temperature was high was simple:
    1) You could hear the battery's cooling fan running at its highest speed. This is not the same fan that is use by the A/C to cool the cabin; this fan is located behind the vent located by the right door and the back seat.
    2) When I press the gas to accelerate, you could tell the battery was not providing power to the traction motor. The engine was running at a very high rpm, the battery state of charge was one bar from full but the car was not using the battery to power the A/C or traction motor. Normally on a hot day, the A/C will drain the battery fairly quickly if you are stopped and the engine is off. In this case, even after 5 minutes the state of charge of the battery was still one bar from full. It is safe to say that the engine was generating the electricity required to run the A/C at that point.
     
  9. PRPrius

    PRPrius Active Member

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    The funny thing is that I do have the windows tinted, (Nano Ceramic window film with 85% Infrared rejection rate). I also had the windows cracked open and the car was parked underneath a large oak three that covered the entire car with it's shade.
     
  10. snead_c

    snead_c Jam Ma's Car

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    Were any warning lights on ? With over 80,000 miles the gas engine thermostat could have malfunctioned but even then a high temp light should have come on. :confused:
     
  11. richard schumacher

    richard schumacher shortbus driver

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    Mine did this for a couple minutes on Friday. It's better to keep moving, to help move more air through the A/C radiator and thus cool the cabin faster.
     
  12. edthefox5

    edthefox5 Senior Member

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    Ok.... bummer.

    If it was my car I would take the traction battery cover off and peek in there for connection corrosion. Somethings going on there.
    Take the cover off & stare at it.
    You may see a problem....if you have the knack.
    If not you may get electrocuted.



    My life...and utter social ineptitude:



    there there....
     
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  13. andyprius

    andyprius Senior Member

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    You did not know what the temperature was in the HV Bat area, you did not measure it, correct? None of us know the design temperature parameters. Your second point that you just made known is that the HV SOC was one bar from the top. That being the case you should have lowered the set point on the AC to MAX COOL and maxed the AC fan for the benifit of the HV compartment. Slowing down, stopping, parking etc; will only increase the time the HV has to lose its excess heat
     
  14. andyprius

    andyprius Senior Member

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    Re: Overheated batteryhe

    All these procedures are helpful, unfortunately heat always flows from hot to cool, thru windows, thru tinting, thru the roof thru the hood, etc. so no matter where you park some heat is going to transfer to the car. My car will absorb heat parked in my garage all day, why, because the garage slowly gets warmer thru out the day. HOT to COLD. I am very interested in your problem because as you see I also have a 2005, so your problem could be my problem. Please keep us informed of any changes for the bad or the good, hopefully good. Keep that AC maxed out to save the HV Battery! :cheer2:
     
  15. 2009Prius

    2009Prius A Wimpy DIYer

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  16. andyprius

    andyprius Senior Member

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    That was an extreme case. The main problem with the air intake is that it is totally open so if you had a heavy problem with dog hair you would not know it, except too late. The fan itself is aPIA to get to, on both the intake and the exhaust there are filters permanently attached. One must remove most/all of battery covers, seats, right rear felt panel as well as disconnect both batteries. The way Toyota builds leads me to believe that they do not want owners to work on their cars. One thing is connected to another thing which is connected to another thing, etc. So:focus: if the OP has a big hair losing dog that would be the problem!:humble:
     
  17. andyprius

    andyprius Senior Member

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    Title: Should be a simple case of Paranoya. There was no overheated battery, only a overheated brain function. :cheer2: