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Full charge sound problem

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by mhragheb, Jan 15, 2014.

  1. mhragheb

    mhragheb New Member

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    I have Prius 2005 , there is no problem and no registered error code,but the problem occur when i drive my car on long down road and the HVB is full then the charging sound rise ,its like "B" mode on high speed,this sound continue while pressing on the break pedal or not but when i press on the fuel pedal or convert to transmission to "N" mode the sound return to normal ,but if i press on the break or leave my leg the sound return again,this happen if the battery is full but when the battery loss some charge everything return without any problem.

    sorry for my language
     
    #1 mhragheb, Jan 15, 2014
  2. bisco

    bisco cookie crumbler

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    welcome to priuschat! the ice is burning off the extra charge the battery cannot accept. 'all systems normal'. all the best!(y)
     
    #2 bisco, Jan 15, 2014
  3. Britprius

    Britprius Senior Member

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    When the traction battery is at 8 green bars it will not accept any more charge so to use up the energy being produced as you go down hill MG1 spins the engine to use the energy being produced by MG2.
    If you brake gently the energy produced is more so the engine is spun faster "increase in noise".
    If you put your foot on the accelerator MG2 will drive the car faster and use energy instead of making it so the engine speed will decrease as MG1 now does not have to use up so much energy.
    Changing into neutral above 50 mph should be avoided as this can over speed MG1 and destroy the transmission.

    John (Britprius)
     
    #3 Britprius, Jan 15, 2014
  4. mhragheb

    mhragheb New Member

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    Thanks, i believe this is the good analysis but why sometimes this noise not found although i use the same road daily and the battery have full at the same time always, i asked my question because i think Toyota engineers make a relay to solve this issue and may be this relay not working always ,this is what i guess.
     
    #4 mhragheb, Jan 16, 2014
  5. Britprius

    Britprius Senior Member

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    The amount of braking you do will alter the amount of charge going to the battery, more braking equals more charge also the level of charge when you start your down hill run.
    There is no relay controlling this, it is done electronically, and is normal. You can if you wish use "B"mode to descend the hill, but this will make the effect even greater. All of this is normal do not worry.

    John (Britprius)
     
    #5 Britprius, Jan 16, 2014
  6. dorunron

    dorunron Senior Member

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    One thing that will help to remove the excess charge is to turn on as many electrical devices as you can. Examples: Electric A/C, blower fan on high, headlights on, etc.

    As stated above, the Prius is simply attempting to use up the excess amount of energy being stored by the regenerative braking system. The traction battery has a limited capacity, and once the capacity is reached or close to being full the Prius will begin to dump the excess energy by spinning up the ICE as illustrated above.

    As bisco says, "all systems normal".

    Best of luck to you and "Welcome to Prius Chat".
     
    #6 dorunron, Jan 16, 2014
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