When to pull the plug?

Discussion in 'Clarity' started by Ken7, Jan 4, 2018.

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  1. JyChevyVolt

    JyChevyVolt Active Member

    Ouch. That sucks. I like to see your Fall, Spring stats. Looks like you don't get that much regeneration.
     
    Last edited: Jan 5, 2018
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  3. Viking79

    Viking79 Well-Known Member

    Usually you integrate the current to and from the battery. Coulomb counting. The display in my and Jy Volt is an estimate used during operation, not from the wall. However, the Gen 2 Volt will report MPGe, which is always from the wall.
     
  4. Viking79

    Viking79 Well-Known Member

    I love when the temp warms up. I don't usually do as well as you are showing there, but much better than the winter. All the cold air slid off the arctic down to the midwest. I am fine if it goes back now ;)
     
  5. JyChevyVolt

    JyChevyVolt Active Member

    Yea
    Yeah, I've seen the kWh use go backwards on long regeneration. On top of the hill, it will show 9.8kWh and then 9.6kWh on the bottom of the hill.
     
  6. Viking79

    Viking79 Well-Known Member

    I hope its just the weather, but I have noticed it reading 9.2 kwh on full charge a few times, which is down from the usual 9.4 to 9.8, however, the engine is running a lot so I don't really trust that number. Will have to do a full cycle without the engine at all, which won't happen until it warms up a little ;)
     
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  8. JyChevyVolt

    JyChevyVolt Active Member

    IMG_20171212_222401434.jpg
    GOM showed 3 miles left.
     
  9. Viking79

    Viking79 Well-Known Member

    Nice, pretty good efficiency. This must be at highway speeds?
     
  10. JyChevyVolt

    JyChevyVolt Active Member

    1. 8 mile local (45 mph) EV
    2. 30 freeway (75-80 mph) CS mode
    3. 2 mile local (40 mph) EV
    4. 2 mile local (40 mph) EV
    5. 23 mile freeway (65 mph) EV & CS Mode
    6. 15 mile freeway & local (65-45 mph) EV

    1500 feet elevation change. The trick is to speed up in CS Mode.
     
    Tony Vo likes this.
  11. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    Why couldn't they just use a generator which puts out a lower voltage? At any rate, speaking as a non-engineer, it seems to me that it should be just as easy (or at least nearly so) to design a PHEV's PEM (Power Electronics Module) and battery pack's BMS as it is to design those for a BEV.

    Indeed. It may seem from the outside that BEVs and PHEVs should have very similar characteristics in their battery packs and charge/discharge cycling, but when you look inside there are actually important differences.

    There are also important (if less pronounced) differences between a 200+ mile range BEV and a ~75-90 mile BEV. Again, the larger pack gets cycled less often, which leads to different design considerations.
     
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  13. Cypress

    Cypress Active Member

    PNW
    Unless you live in a hot climate, and want to remote start the cabin conditioning to cool it off.
     
  14. Cypress

    Cypress Active Member

    PNW
    That all seems like too much hassle for the average car owner. Most BEVs seems to have a built in capacity buffer, so you aren’t really ever charging to 100% anyway. My EVSE can be programmed to limit the charge. So could be handled on the charger side for cars without that ability. And at the moment, not too many long range EVs on the market. For the short range EVs, only charging to 80% and discharge to 30% means having a very limited range and no buffer if you have unexpected travel needs.
     
  15. dstrauss

    dstrauss Well-Known Member

    That's never stopped me (talking beyond the edges of what I understand)...:confused:;):D

    So in that tradition, let me posit another non-engineer theory - PHEV's carry the burden of needing to run in hybrid only mode - and from my Prius days those do not use large battery packs (compared to PHEV's and BEV's) so the ultimate limit is that you must maintain a bottom level capacity (2-4kWh on the 17.5kWh pack?) to function as an HV - supplementing ICE power, shutting the ICE off in idle (which is the Prius' primary trick to achieve spectacular mpg in city driving - as I've told many friends, yes it has a smaller more efficient engine, but the "smoke and mirrors" is shutting off the gas hog whenever possible), running AC from the battery instead of ICE, etc.

    So I would think a PHEV's battery pack is going to be inherently less efficient than a BEV because of it's split personality - think of the PHEV as Dr. Jekyll and Mr. Hyde...

    So says the dummy...
     
    Last edited: Jan 5, 2018
  16. jim

    jim Active Member

    FYI I don't like to keep our car plugged in. What if the area got hit by lightning, Very rare but why worry about it.
    We have 2 Electric cars so we shuffle the charging cord between them. Our KIA SOUL EV can sit a week and not lose any charge. Our 2012 Tesla S 85 will use phantom power and drop 5 or 10 miles in a day. We only charge to 80% most for the time since it still shows over 200 mile range. Even if we were away for 2 weeks they don't need to sit plugged in.
    Most cars don't have a 80 or 90% setting so they always got to 100%. Granted the automakers always keep 5 or 10% in reserve but why push it. I love the Tesla setup where you can set the % charge , time of day etc. It even shows the power input when you charging. Most other plugin vehicles are lucky to have a light to let you know your charging or done. Tesla does it best.
     
  17. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    Yes, which IMHO is why people should take car to make sure any BEV they buy has a range significantly higher than their anticipated daily driving needs. If you have a 200 mile BEV, then only charging to 80% will get you more distance than if you have an 85 mile BEV and you charge to what the car's BMS tells you is 100%, which is more likely somewhere around 90-96%. If you have only a single car and are worried about having to make an unexpected long-range emergency trip, then that single car shouldn't be a BEV; it should be a PHEV or a gasmobile. Many EV owners have two cars, with the other car being a gasmobile, which they can use for those rare emergency journeys.

    One size does not fit all. There is theory and there is practice. I've detailed the theory of what will maximize battery life; what you do in practice will have to fit your individual practical needs, not the theory.

    I'm an EV advocate, but that doesn't mean I'm going to ignore the reality that at the current state of development, BEVs are not for everyone. The car anyone chooses has to fit their lifestyle, not some ideal.
     
  18. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    Unfortunately, when it comes to engineering principles, the word "efficient" has far too many meanings. I'm not quite sure what you mean here. Perhaps you'd care to be more specific?

    I've certainly seen comments that PHEVs have disappointingly low fuel efficiency (MPG... and I mean real MPG, not fake MPG or MPGe or whatever) ratings as compared to non-plug-in HEVs. But comparing PHEVs to BEVS in EV mode, I think at least the better-designed PHEVs hold up their end.

    Let's compare:

    2018 Volt: 106 MPGe
    2018 Hyundai Ioniq PHEV: 119 MPGe
    2017 Leaf: 112 MPGe
    2018 Bolt EV: 128 MPGe

    (My apologies for using a fake metric such as MPGe, but a miles/kWh comparison may be less accurate since EV makers don't reliably distinguish between total capacity and usable capacity for their battery packs.)

    Looks like the Volt compares reasonably well to PEVs of its generation. I didn't expect it to compare well to the very newest EVs, such as the Tesla Model 3 or the Bolt EV. The Ioniq PHEV has better energy efficiency, but only by sacrificing power, where it seriously under-performs.
     
  19. dstrauss

    dstrauss Well-Known Member

    @Pushmi-Pullyu - Sorry for my lax use of "efficient" - I am thinking in a more global sense of the useful capacity in EV mode between a BEV and an PHEV, as teh PHEV has to maintain a reserve for hybrid mode driving beyond the EV limits.
     
  20. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    I wouldn't suggest most PEVs need to sit most of the time plugged in, either. But with most of the USA in the grip of an arctic cold snap over the past week or more, if you currently find no need to leave them on the charger overnight then I'm guessing you live in a region where it rarely if ever gets bitterly cold in wintertime!
     
  21. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    So then, you meant "efficient" in the sense of using more of the stored energy to actually send the car down the road, when comparing BEVs to PHEVs?

    Well in general I agree with what I think you are saying, which is that BEVs are more efficient in using energy to push the car down the road than are PHEVs. As you say, PHEVs have to be designed to operate both as gasmobiles and as pure EVs. And just as with anything else, something designed to do two different things probably won't do either as well as something designed to do just one thing. All engineering is a compromise, but some compromises are worse (or less efficient in various ways) than others.

    But there is one thing running counter to that, and it's this: BEV drivers worry a lot about range anxiety. Or at least, they have to spend some time planning ahead so they can avoid that as much as possible. And that means that a BEV driver is going to take care to ensure he will wind up at the end of the day with some safety margin of range left in the car. If he thinks he won't be able to do that, then he -- or rather many BEV drivers but not necessarily any individual one -- will drive his other car that day, and that car is likely to be a gasmobile.

    I wish we could get statistics showing electric-powered miles vs gas/diesel-powered miles on the basis of drivers, rather than cars. A PHEV driver never needs to switch from his PEV to a gasmobile, since his PEV can switch from one mode to the other. Just how many gas-powered miles are BEV owners putting miles on their gasmobiles because they want to avoid range anxiety from driving a BEV that day?
     
    dstrauss likes this.
  22. loomis2

    loomis2 Well-Known Member

    BTW, just to get this out there, my 2013 Leaf does give me the option to charge to 80%. I've never used that option personally, but it is there. I kept reading that Nissan doesn't have any option besides 100% so I wanted to set that straight.
     
    Domenick likes this.
  23. JyChevyVolt

    JyChevyVolt Active Member

    The older leaf had the 80% option. The newer leaf don't. Manufacturers can increase the EPA range by eliminating the 80% option. The Bolt EV uses hilltop reserve to get around this issue.
     

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