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On the fly charging

Discussion in 'Rivian' started by Rick Macpherson, Jun 5, 2020.

  1. Rick Macpherson

    Jun 5, 2020
    1
    Is it possible to charge your Rivian while traveling with a portable generator to increase range while towing airstream?
     
  2. Domenick

    Domenick Administrator
    Staff Member

    Aug 10, 2017
    2,145
    Typically, electric vehicles can't charge while in operation. I haven't seen any mention of Rivian being able to do this.

    In the video in this post, a generator is used to charge an EV but it's not as straight-ahead as you'd think and it's a pretty heavy piece of equipment to haul around. The Rivian vehicles will all have large battery options and offer lots of range. With various charging networks really starting to create good coverage across the country and Rivian itself announcing charging at adventure destinations, I don't think many would find an onboard generator the best solution.
     
    EyeOnEVs likes this.
  3. MarcyB

    MarcyB Rookie

    Sep 15, 2019
    8
    We're wondering about using the solar panels on our travel trailer for auxiliary charging, but like Domenick says, it would be anything but straightforward. Especially while driving. But we can envision doing it while parked - using our inverter to provide 110V AC (standard wall plug) for slow charging of the truck. It wouldn't be much, but in the summer we have excess energy and it would be great to put it to practical use. Looking forward to testing it (next year??) and will report back.
     
    Domenick and EyeOnEVs like this.
  4. EyeOnEVs

    EyeOnEVs Karting

    Mar 5, 2019
    64
    The short answer is no. Read this in another forum and I believe the source of the information came from Rivian.

    Ah, what video? :confused:
     
  5. Domenick

    Domenick Administrator
    Staff Member

    Aug 10, 2017
    2,145
    Nice catch! I've added the link to the post now, but here's the video that's in it.

     
  6. Domenick

    Domenick Administrator
    Staff Member

    Aug 10, 2017
    2,145
    I do love the idea of solar on campers. I think we'll see a lot more of this, along with battery storage in the future.
     
  7. ajdelange

    ajdelange Rookie

    Mar 22, 2019
    20
    On the fly charging isn't going to be available for a long time simply because there isn't enough surface area on a vehicle to mount enough PV cells to make much of a difference. A good panel will produce about 300W per square meter it is pointed directly at the sun, the sun is well above the horizon and there are no clouds. People seem to have trouble grasping that you can't practically mount a tracking array on a moving vehicle and even if you could the sun isn't up all day nor at all on some days.

    But yes, you can charge when parked from a generator or solar arrays. Just don't expect much from either. The video shows a 7 kW generator. That's equivalent to about 28 panels on a clear day near the summer solstice.
     
  8. EyeOnEVs

    EyeOnEVs Karting

    Mar 5, 2019
    64
    Then it's probably best you're not on the Lightyear One's engineering team. ;)

    "First Ride: Lightyear One solar car gets 450 miles on 60kWh, even when sun isn’t shining"

     
  9. ajdelange

    ajdelange Rookie

    Mar 22, 2019
    20
    The engineering team should have no problems with me as a member (other than my being an over the hill crusty old fart) because they use the same physics I do. It would be the marketing folk that wouldn't want me around as I much less disingenuous than they. Go to their website and look at the numbers:

    "The 12 km/h added by the solar roof and hood during daylight exposure extends the range as you drive."

    From elsewhere on the site one can determine that the car's power consumption is 144.5 kWh/mi. That's remarkable compared to, say, one of the Teslas. My X turns in 270 or so in town and about 300 in high speed freeway driving so I'm sure the lighter M3 is probably between 220 and 240 (?). In any case clearly what these guys have done is strip out every bit of weight and drag they could and eked out every fraction of a percent of efficiency they could. As the Tesla efficiencies are in the 90's there isn't much room there so clearly it's in GVW and drag that Lightyear has obtained this incredible consumption level. I take back what I said about motor efficiency - they are using hub motors thus eliminating mechanical transmission losses. Perhaps 145 Wh/mi remarkable for a small car. I can't find any size, weight or performance data on their site.

    It is also possible to calculate their battery size at 65 kWh based on consumption and their stated maximum range of 450 miles on a full charge.

    Putting all this together we can calculate that the PV array produces a whopping 450 W! If you set out from home with a full charge in the early morning and the sun shines brightly for the 5 hours it can do max at mid lattitude in the summer you will have an extra 37.5 miles range. That's 8.2% extra - nice to have for sure but not terribly exciting. Noting that the sun does not shine every day in summer or winter and that insolation is less in the winter than the summer and less at higher latitudes away from the summer solstice you will see why I don't get too excited about the prospects of charging from solar panels on the roof of the car. Thus to think that you can set out on a sunny day and drive forever is very naive unless your destination is less than 450 miles away in which case you don't need the solar at all.

    Keep in mind the history of these guys. They came from a bunch who have been entering the Darwin to Adelaide solar car contest for years (and won it several times). Other than a few months in "the wet" the weather along the Stuart is always "fine" and it is possible, in a test vehicle, to make that whole run without recharging.
     
    Domenick likes this.
  10. ajdelange

    ajdelange Rookie

    Mar 22, 2019
    20
    A little more perspective: The long range MS is now EPA rated at just over 400 miles and has, I believe, the same battery as the X which has a discharge capacity of about 92 kWh. That gives the S consumption of 229 Wh/mi.
     

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