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Need advice for a long trip without access to charging.

Discussion in 'Prime Fuel Economy & EV Range' started by mistermojorizin, Jun 19, 2019.

  1. mistermojorizin

    mistermojorizin Active Member

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    I've been doing a ton of reading on here, but I'm still confused with all of the different modes and driving techniques(hv mode, ev mode, charge mode, B gear, warming up the engine by going hybrid-->electric, ratcheting up by going hybrid-->electric-->hybrid). So I'm going on a long trip, about 220 miles each way done the 5 (approx. 75 mph) and over the Grape Vine (approx 70mph) and into LA. I'll be doing some trips around LA while I'm there. Then I'll do everything in reverse. Here's the thing, I currently don't have access to a charger and won't for the duration of the trip. I've got about 15mi electric range right now and a full tank of gas. What are the best strategies to maximize my range? I'm not talking hypermiling, just what modes I need to be in?

    1. Surface streets to the highway (45mph, 3 miles, 100 degrees F). Should I use HV mode or use up some EV mode while warming up the ICE?
    2. Freeway @ 75mph mostly flat, 100 degrees F, lots of miles. This one's easy, HV mode.
    3. Freeway @ 75mph going up a gentle incline before the grapevine. Assuming HV mode. Or Charge mode?
    4. Steep incline up the Grapevine. Assuming HV mode, but there's arguments for using up some EV or going into Charge mode?
    5. Top of the grapevine, pretty flat for a bit. HV mode?
    6. Going down the grapevine, should I use EV mode in B gear to charge? Or EV mode in D gear with DRCC? This is the regen part. Does it change one of the previous questions to EV? Should I have killed all EV by this point? If so at which step?
    7. Driving on 405, 70mph traffic allowing. HV mode?

    Is there just like a proven strategy with going up hill, depleting EV range, regen down hill. When not able to charge. Am I better off using charge mode at some point to have EV available at another point?
     
  2. bisco

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    with 15 miles of ev, the only thing that will help is to drive conservatively. none of the modes matter. study them when you have time to practice with them.
     
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  3. jb in NE

    jb in NE Senior Member

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    I would start with a full EV charge if you can get it. That's the maximum energy in the vehicle with a full tank of fuel.

    Surface streets to highway, use EV. Then on the highway use HV. Going up the Grapevine (nice climb), use EV as necessary to get your charge down to (I'm guessing here, haven't run that hill in my Prime) 60%. On the downhill side, put the car in EV and B mode and don't touch the brakes. You will recapture energy up to 100% of the battery charge. Then back to HV for the rest of the trip to LA.

    Then run EV around town in LA as long as you can. If you can avoid starting the engine at all, that improves around-town efficiency, so it would be good to hit LA with a full battery. Note that if you don't exit the Grapevine with a full battery, if it's above 80% charge then charge mode won't put anymore in, so you want to top off the battery with regeneration along the way (slowing down in traffic, exits, etc.)

    Repeat in reverse on way home. Edit - based on what you saw southbound on the Grapevine, you may need to adjust your battery level accordingly on the way home (i.e. don't top the hill with too much battery charge).

    You will be surprised how much energy you can put into the battery going down a long grade like the Grapevine. I could get 50% charge coming out of the mountains on I-70 in Colorado.
     
    #3 jb in NE, Jun 19, 2019
    Last edited: Jun 19, 2019
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  4. Salamander_King

    Salamander_King Senior Member

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    With 220 miles each way, total 440 miles, you can be back where you started with a single tank of gas easily. You can try to save EV range for in city drive and/or congested roads, but you will be driving mostly on HV only. If you can keep your speed less than 70mph, you will be able to get more than 60mpg on HV only. I routinely drive over 600 miles with a single tank.
     
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  5. jb in NE

    jb in NE Senior Member

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    The modes definitely matter on the Grapevine. You can put a lot of regeneration into the battery on the downhill into LA; up to a full charge.
     
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  6. bisco

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    in what mode?
     
  7. jb in NE

    jb in NE Senior Member

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    Additional note. If you didn't have the Grapevine along the way and it were flat, I would recommend leaving home with a full EV charge, run in HV all the way to LA, drive around LA in EV, then back home on HV. If there is any EV left in the battery nearing home, then go back to EV and use the remaining battery.

    This assumes it is cheaper to run on EV from the wall than gas from the tank.
     
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  8. jb in NE

    jb in NE Senior Member

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    EV mode and B - this will put all the regeneration in the battery up to 100% charge, at which point it will spin up the ICE for engine braking.

    If the EV is totally exhausted when you want to do this, the fix is to go to Charge mode and put a few percent in the traction battery, then you can run in EV and B mode. You can't run in EV mode with 0% indicated traction battery.
     
  9. bisco

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    what would happen in d and/or hv/ev auto?
     
  10. mistermojorizin

    mistermojorizin Active Member

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    First, thank you so much for the quick and detailed response.

    Just to clarify, that's 60% of the part of the battery reserved for EV, or 60% of the whole battery? Also, isn't it better to completely deplete the EV range here, just so that none of the downhill regen could be possibly wasted?

    My one concern is what if the B mode slows the car too much, and then I have to use EV to accelerate? Also, when talking about regen braking, is it better to coast, press the brakes lightly, or press the brakes firmly? I thought I read something in the manual about the regen being the best when coasting then pressing the brakes hard.

    So better to use up the EV range in LA and not save it for the drive back?
     
    #10 mistermojorizin, Jun 19, 2019
    Last edited: Jun 19, 2019
  11. mistermojorizin

    mistermojorizin Active Member

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    Thanks for the quick reply. This actually raises a question I had reading one of the stickies here. It was a thread on the pulse and glide technique, but ignoring the glide part for my purposes. It said that the ICE is most efficient under heavier load, so it's better to accelerate briskly rather than accelerating gently. It said that this is actually true for traditional ICE cars as well. I was shocked because I always tried to accelerate conservatively and keep low revs. So the question is, what's better inHV mode, slow acceleration or pulse acceleration which would put load on the ICE and keep it in most efficient range, supposedly?
     
  12. jb in NE

    jb in NE Senior Member

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    60% indicated - this is just a guess based on my last drive over the Grapevine. I haven't driven that hill ever in my Prime.

    I wouldn't deplete the EV charge down to zero, because I don't think you can fully charge going down the hill. If in doubt, shoot for something lower than 60%, maybe 40-50%.

    If B mode slows the car too much, put your foot lightly on the throttle and you will see the regeneration decrease on the dash display. If you increase throttle pressure until the regen/power is right on zero, then the car is essentially coasting. On that long downhill, unless maybe in a slight flatter spot, you won't be using EV power to propel the car, you'll be using the throttle to regenerate less.

    You regenerate by pressing the brakes lightly. In B mode, the car is already doing this by itself. If you keep the regeneration bar a bit above the bottom limit, you are regenerating and not friction braking.

    My opinion, yes. If you can avoid running the engine in LA, that's no warm-up cycles, etc. Even if you hit the Grapevine headed home with zero battery charge indicated, when you hit the flat at the top go to Charge mode for a mile or so and get a few percent EV charge. Then EV and B on the way down, get some EV and use that at the end of your trip to get you home.

    On the open highway, I just put it on cruise and let the car run. At 73 mph actual, on flat ground my Prime engine RPM are typically around 1800 or so (pretty low). I'm not sure how effective pulse and glide is at 70+ mph, since I haven't used that method.
     
    #12 jb in NE, Jun 19, 2019
    Last edited: Jun 19, 2019
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  13. mistermojorizin

    mistermojorizin Active Member

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    Just to clarify, because I'm dense, so 60% of the EV portion. Also, is there a screen that indicates percentages? The screen I use now is the split screen view with a diagram of the battery with the 2 parts shaded different colors. I've been looking for the screen that gives numerical percentages but haven't found it yet.
     
  14. jb in NE

    jb in NE Senior Member

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    If you want data overload, get Hybrid Assistant, which shows a lot more data in real time and also records your trip and will generate quite a bit of useful information in graph and chart form for study later.
     
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  15. bisco

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    pulse and glide is only beneficial on back roads. there is something called super highway mode or some such, but i never understood it. i can't drive long distances without cruise anyway.

    as for pulse rpm's, i'm not sure anyone gas determined the sweet spot for the gen 4 engine.

    on the gen 3, i pulse just above the eco line on the hsi, gets me great mpg's, but don't know if that is the sweet spot either. it is a little faster acceleration than i was using trying to be conservative
     
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  16. jb in NE

    jb in NE Senior Member

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    Here is how I keep my display configured - I like the battery percentage on the right there. The only numbers that matter on the battery percent are 0-100%, which is actually about 23% to 80% of the battery range. Below 0%, you're driving a Prius in HV mode with a big battery. Above 0%, you can use the EV mode capabilities of the car.

    Look in your owner manual under "Hybrid System Indicator" and it will give you some basics on that display. I can't recall where the settings were to put the battery percentage on the display, but it was in the settings options for that display panel.

    2019-06-19 19.53.58.jpg
     
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  17. jb in NE

    jb in NE Senior Member

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    I can't recall the specifics. D just changes the background regen rate. I never run EV auto since I want full control of my EV battery capacity - for me it's either HV or EV, never EV auto.
     
  18. mistermojorizin

    mistermojorizin Active Member

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    [​IMG]
     
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  19. jb in NE

    jb in NE Senior Member

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    That's it. I set it once when I got the car and haven't changed it since.
     
  20. mistermojorizin

    mistermojorizin Active Member

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    Thanks, I just posted it for my own benefit and future reference.