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Thread: Regen Charging

  1. #1
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    Regen Charging

    Hi All

    Just found some information on the strategy Ford uses with regenerative braking. Due to concerns of possible wheel slippage in ice and snow, Ford reduces regen braking as the ambient temperature drops below 60F. Above 60F, 100% of regen is possible. Below 40F, 10% effectiveness or less is available for charging the battery. Ambient temperatures between 60-40F reduce regen in a linear relationship.

    This information is important to me because I use regen with the fake shift in "L" to return to EV ASAP in city driving. Knowing the outside temperature will assist me with battery SoC (state of charge) management to get maximum MPG.

    Cheers

    GaryG

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  3. #2
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    Thanks for the research but I doubt that you have to worry too much about cold weather in your location. Those of us in the colder climates will just have to expect a longer charging time before our battery is ready for another round of EV mode.

  4. #3
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    Gary,

    Does this imply that there exists a temperature point where driving in L is going to be more efficient than driving in D (Assume this driver is not uber advanced in hypermiling)?

    Cris

  5. #4
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    Quote Originally Posted by cshupp View Post
    Gary,

    Does this imply that there exists a temperature point where driving in L is going to be more efficient than driving in D (Assume this driver is not uber advanced in hypermiling)?

    Cris
    Driving in "L" will NOT reduce mpg because of losing all the ability of coasting. You can take the regen benefits of the "L" position without driving in it all the time by shifting to it when slowing down. I use "L" as I would in a manual transmission to slow me down to save the brake pads. The other benefits of going EV and charging the battery are the icing on the cake with our FEH/MMH vehicles.

    In the article I wrote for CleanMPG.com, I conducted a steady state speed test and used "L" by accident during the test. The results 50mph and under showed a big drop in MPG because of regen flowing in and out at those speeds. You don't need that with a full battery at all. Higher speeds caused more acceleration due to wind resistance, so there was less coasting and the chance for regen at higher speeds. In addition, in a steady state speed with the battery full, you don't want to put the FEH/MMH in a negative split mode. A negative split mode is where the generator (MG1) is using power to reduce the torque of the ICE. This is the worst mode for MPG because your using energy to reduce energy. Regen just compounds the problem with Hybrid Drive being in the negative split mode.

    Bottom line, drive in "D", use "L" for slowing and use "N" for coasting. Some of you may see an increase in MPG by driving in "L", but you will see a much better increase when shifting to the mode that helps you the most.

    Billy, it's true I have far less temperatures here in So. FL. below 60F, but I have a few. By knowing this information, I'll adjust how I use regen in "L" but the reason I posted this about regen is for others. It's not always the battery that prevents charging as you can see. Maybe you folks should take this information and use regen when the temperature is higher in the day to charge the battery with regen before parking for the night. A full battery in the morning cold might help them warm-up mornings MPG.

    GaryG

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