Alternator Management System (AMS)

Discussion in 'Fuel Economy' started by UberJager, Apr 25, 2020.

  1. UberJager

    UberJager Member

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  2. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Too bad they don't sell that car here. My son-in-law in England has a Kia that might be
    the twin of the i10 , not sure. But I think his has a 1.0 turbo engine.
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  3. UberJager

    UberJager Member

    This technology is available in many Hyundai models.
    i10, i20, Accent, i30
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  4. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Yeah , but here : no Accent hatchback. Sedan only.
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  5. S Keith

    S Keith Well-Known Member

    Honda has been doing this for 20 years. Unfortunately, they're much more aggressive and rarely push the 12V to more than 80% SoC, so normal operation is typically between 70 and 80% SoC - which reduces the life of the battery.

    Many domestic models have adopted a version of this technique as well, but it looks more like the linked video than how Honda handles it.

    Lastly, I drove a Hyundai with this system, and I'll be damned if it's not just as bad as Honda. I had a plug-in voltmeter/charger in the power port, and it was annoying as hell. This thing would sound an alarm if the voltage went below 12.0V, and this stupid car, which I otherwise enjoyed driving for a week as a rental, would run the 12V from 11.7 to 14.0V in cycles - which will reduce battery life.
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  6. UberJager

    UberJager Member

    Smart alternators: old idea ...

    Before undertaking this little experiment, I had little doubt that alternators exact some fuel consumption penalty - the question was just how much. It's not hard to find examples where alternator use is minimized or abandoned entirely, either to maximize engine power or reduce fuel consumption:

    - Drag racers are known to run alternator-less (or switch them off) when racing, for example.

    The super-efficient Honda Civic VX used intelligent alternator control.

    - The high efficiency Honda Civic VX and CRX HF models reduce alternator charging under certain cirucumstances. The VX computer instructs the alternator to drop from 14.5 volts to 12.5 (ie. not charging the battery) when all of the following are true:

    - Load below 10A
    - Speed below 40 MPH
    - Engine speed below 3600 RPM
    - Coolant temp above 140 F
    - A/C off
    - Intake air temp above 65 F
    - Brake switch off
    - Fuel cut-off not active

    In other words, the alternator is essentially "idling" when the load on it is low, the car is warmed up and being driven gently. Note that the alternator reverts to normal charging when braking or decelerating (fuel cut-off mode), which is like a simple form of regenerative braking found in modern hybrids and electric vehicles. (Thanks to Randy for the VX info.)
  7. RedylC94

    RedylC94 Well-Known Member

    My Prius does its version of this questionable stunt, too. Voltage drops when the lights are off, transmission is in D, and battery compartment temperature is above some point.

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