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Battery vent (?) and low battery charge?

Discussion in 'Gen 2 Prius Technical Discussion' started by susieeQT, Jun 21, 2016.

  1. susieeQT

    susieeQT New Member

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    So, I'm new to all of this and I don't speak car so please bear with me! I own a 2005 Prius with about 145,000 miles on it. I love it. However, I've noticed that lately, the vent in the back by the window will come on and make a lot of noise. Some research has told me that this is the air vent for the battery that is in the back, and usually comes on when the temps are higher and the battery is starting to get a little overheated.

    It got up into the 90's here today, and I noticed that the vent would come on a lot. Even after I'd leave the car off for a short time, not long enough for the inside to get very hot, it would still do it. I then noticed that my hybrid battery charge was below halfway, which I'd never seen before. I stopped the car and left it in the shade for a couple of hours, and after I came back the battery was still low. It's my understanding that it's supposed to charge when the car is off or stopped.

    Can someone please explain to me what might be going on, or if the two could be related? I don't know much about the hybrid batteries, and I feel like I'm missing a lot. Should I be concerned at all?

    My car has been doing the vent thing a lot over the past few days.
     
  2. bisco

    bisco cookie crumbler

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    welcome! your car is fine, and all that is normal. you might hear the cooling fan anytime, but especially as the weather gets warmer.
    the battery can run anywhere from 8 green bars, down to 2 purple bars, when the engine will come on to charge it.
    it does not charge when the car is off. you're all good, all the best!(y)
     
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  3. S Keith

    S Keith Senior Member

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    Bisco, I disagree. Her fan is more active than mine is here in AZ's recent 113-118°F heat.

    How could a car possibly charge if it's off? From where would that energy come? Magic is not a real thing.

    Do not spare your A/C. Run it and keep you and your battery comfortable.

    Keep watching your battery gauge. If you notice that it runs up and down faster than usual, then you likely have a battery failure on the very near horizon. Consistent battery fan operation (loud), failure of the ICE to shut off when stopped and accelerated gauge movement are all symptoms of potential battery failure.

    I would encourage you to run the discharge test in my signature. Note that you should only do it first thing in the morning when the outside temperatures are as low as possible and the car has been sitting all night.

    Good luck,

    Steve
     
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  4. susieeQT

    susieeQT New Member

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    I was told when I bought the car that the matters would charge when the car was off. Never thought much about it. Thanks for informing me otherwise!

    I just started watching the battery gauge today, so I will keep an eye on it over the next week and see what it does.

    I know very little about cars....what is ICE? What does it look like when it fails to shut off, like you mentioned? Are there any other things I should watch for?
     
  5. susieeQT

    susieeQT New Member

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    Thanks! I'm glad to know that it's pretty normal :) I usually keep it on the other screen, I just flipped over to that one today to check out the battery gauge. I don't usually keep my eye on it, mostly because I don't know what to look for. I guess it's time I learn!
     
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  6. S Keith

    S Keith Senior Member

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    Charging a battery requires an input of energy.

    ICE = Internal combustion engine or the gas burning engine. When you come to a stop, I suspect you notice that the car isn't running. If it continues to run while you are at a stop, it means your battery is low, or there is a problem. In normal conditions, the ICE shuts off the vast majority of the time.

    It's not normal in the conditions you describe. I live in AZ where we are currently experiencing > 110°F weather. I rarely hear my fan. I also log my battery data with most of my daily driving, and while my fan runs most of the time, it runs at lower speeds that are difficult to hear - particularly with A/C and road noise.

    I really recommend you do the following:

    How to test HV battery state of health on your Gen 2 (answer) | PriusChat

    If you can operate your vehicle controls and read a watch, you have more than enough skills to get it done. In your case, you can skip disconnecting the 12V battery. Conducting this test will give you an idea as to the health of your battery.

    Your car is of sufficient mileage that battery failure is relatively common. Here in AZ, I have seen failures happen between 90 and 185K miles with the more typical being in the 130-165K mile range.

    Again, do NOT spare the A/C. Even if you think you need to turn off the A/C to get better mileage or in some way reduce stress on the car - DON'T. Keep you comfortable, and your battery will appreciate it. I like to make sure a couple vents are pointed in the direction of the fan intake vent to ensure the battery is fed cool air.
     
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  7. bisco

    bisco cookie crumbler

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    susie, i will defer to s kieth on this one. where did you buy the car, how long have you owned it, years/miles?

    perhaps you may want to spend a hundred dollars or so to have the dealer check it out.
     
  8. susieeQT

    susieeQT New Member

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    Thank you for the information. I'll check hat out, and most likely run the test you suggested.
     
  9. susieeQT

    susieeQT New Member

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    I bought the car from a small dealership, owned by a good family friend. I've had it almost 2 years, and it has about 145k miles on it. I'm definitely considering taking it somewhere this weekend to get it looked at.

    Should I take it to a place like PepBous, or straight to Toyota?
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    I'd vote Toyota, the hybrid battery is beyond Pep Boys' scope. They have techstream, and do an assessment of the individual battery cells in the battery, for around $100 I think.

    @S Keith know's hybrid batteries, I'm reluctant to disagree with anything he says, but: personally I've found running AC does squat to drop the battery temp, monitoring the temp and fan speed with ScanGauge.
     
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  11. S Keith

    S Keith Senior Member

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    You are in a more mild climate than us folks in the Southern half of the U.S. A/C makes less of a difference for you and may not be as noticeable.

    I monitor the incoming air temp and the 3 exit temps. In 15 minutes of driving and A/C use in summer weather, it pulls the inlet air temp down to within a few °C of the thermostat setting, and the TG1-3 values tend to drop a few degrees. My STARTING temps are 45-50°C for all four.

    If you don't have any codes, Toyota will just tell you that you "probably need a new battery."

    15 minutes of your morning and the discharge test will confirm that.
     
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  12. RRxing

    RRxing Senior Member

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    I noticed the drop in battery temp yesterday after heading home in 85 degree outside temp. Started with AC off and all four windows open - batt temp was 89 degrees. Later on, closed the windows and turned the AC on - batt temp dropped by 4-6 degrees.
    Your Mileage May Vary, of course.
     
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  13. Dxta

    Dxta Senior Member

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    Heheheheh! ICE, mean ice cream!. I'm joking though. It means the internal combustion engine of your car.
     
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  14. Mendel Leisk

    Mendel Leisk Senior Member

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    And we used to get along with just "engine", everyone understood it. The compulsion to fluff it it up to Internal Combustion Engine is pure cargo cult.
     
  15. edthefox5

    edthefox5 Senior Member

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    Im with keith. Its been ungodly hot down here all summer and I never hear the fan. Ever. Only heard it once in 10 years.

    If the fan is on full blast and that happens a few times the hybrid battery is probably toast at that age & miles. At the very least your incuring module expansion and then the inevitable leak and then ground fault.

    Its a 12 year old car. Its way way past end of life for the battery. I'm afraid the lovely OP is about to get herself some battery education.
     
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