TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

Tesla Energy motorhome

Discussion in 'Cars and Transportation' started by jeff_adams, May 1, 2015.

  1. jeff_adams

    jeff_adams Member

    Joined:
    Mar 18, 2013
    Messages:
    617
    Location:
    Monterey
    Now that Tesla will be offering battery banks, I'm wondering which coach work company will be the first to market with "Tesla inside". I don't expect the aerodynamics to work for an electrical powered motorhome (larger than a VW bus) but it could make a lot of sense to get rid of the lead acid Marine batteries and the propane tanks. Silent campgrounds without generators running would be a huge blessing.

    Perhaps adjustable heavy regen braking could be developed as well? Make it safer to drive a big bus down steep grades AND recharge your battery without burning up brakes. Win-win.
     
  2. davewill

    davewill Member

    Joined:
    Feb 5, 2014
    Messages:
    433
    Location:
    San Diego, CA, US
    I would think that Plugin-hybrid tech would make a lot of sense for a motorhome. Should improve efficiency, plus the ability to charge up while at the campground, or conversely to run the motorhome when not plugged in. Could be a bummer to have a motorhome blocking 4 or 5 charging stations while they top up, though. :)
     
  3. SmartElectric

    SmartElectric Active Member

    Joined:
    Jul 9, 2014
    Messages:
    1,077
    Location:
    Toronto,Canada
    Having rented an RV three times, I too was curious, so did the math.

    1. RV uses 4x more gas than a standard sedan to drive the same distance.
    The 36 foot "A" class I rented got 6 mpg on a good steady drive, and 5 mpg in the mountains.
    If 85kWh battery gets you 240 miles in a Model S, the same storage gets you 60 miles in an RV.

    2. Tesla Powerpack 100kWh system is priced at $250/kWh according to Elon:
    Elon Musk on Twitter:

    3. Let's say you need a comfortable 200 mile range between recharges.
    You'd need to have the room for three fridge sized 100kWh battery systems and $75000 lying around to fund it.

    - - - Updated - - -

    The hybrid idea is cute, and you don't need much battery to do that, but it doesn't help much on the open road where the majority of RV driving is done.

    For sure improved battery systems compared to the standard lead acid used in RV's to run the fridge and lighting when on the road would make sense though.
     
  4. stevezzzz

    stevezzzz R;SigS;P85D;SigX

    Joined:
    Nov 13, 2009
    Messages:
    6,062
    Location:
    Colorado
    You sure about your math, SmartElectric? If the Model S gets 89 mpge, wouldn't 240 miles in a Model S equate to roughly 20 miles in a 6mpg motor home?
     
  5. SmartElectric

    SmartElectric Active Member

    Joined:
    Jul 9, 2014
    Messages:
    1,077
    Location:
    Toronto,Canada
    Yes, pretty sure.

    The same sized V10 engine in a car similar to a Tesla would get 20+mpg on the highway.
    In an RV, due to weight and air resistance, the same V10 gets 5mpg.

    That is a 4x difference on the same powertrain.

    The 4x is due to weight and aerodynamics, both of which are notoriously bad in an RV. ;-)
     
  6. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley

    But EV motorhome would be way more than 6MPGe. Using his 1/4 rule, the eMotorhome could be 22MPGe. Regen and overall efficiency should be much better than an ICE.
     
  7. dsm363

    dsm363 Roadster + Sig Model S

    Joined:
    May 17, 2009
    Messages:
    18,235
    Location:
    Las Vegas, NV
    Isn't the first post talking about replacing generators while parked anyway?
     
  8. pmadflyer

    pmadflyer Member

    Joined:
    Jan 8, 2015
    Messages:
    347
    Location:
    Shawnee, KS
    Are the two modules in the 10 kWh Powerwall the same as the 16 in the 85 kWh car pack? I could see an unintended, but interesting market for the Powerwall being electric conversions. I will go out on a limb and say that if the modules are in fact the same, the coolant system could be modified to run through a radiator. I know that this isn't explicitly what this thread is about.
     
  9. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,743
    Location:
    Texas
    I don't think anyone but Tesla knows at this point, but because Tesla has said that the Model S battery pack can be used in stationary applications after it's EOL as an automotive battery, I'd assume that the Powerwall was designed with this in mind.
     
  10. jeff_adams

    jeff_adams Member

    Joined:
    Mar 18, 2013
    Messages:
    617
    Location:
    Monterey
    Yes, exactly. Go electric on everything except the motor.. Maybe someone can design a roll up solar canopy you can employ when camping to charge up the powerwall with the added benefit of providing shade....
     
  11. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    2,933
    Location:
    Delaware
    How much does it have to help to be a good idea? The motorhomes you're talking about appear to be the ones using large pickup truck engines - in their 2 mode hybrid program GM demonstrated that even with a little battery and 300+ horsepower engine, minor aero tweaks, Atkinson cycle, and hybridization were enough to gain 20% better economy on the open road (and much more in the city.)

    With a larger battery and an engine downsized to meet the actual demand, more improvements are likely possible. A quick analysis suggests that even at 6 mpg, the motorhome is still only averaging about 90 kW to the road at 65 mph.

    I'm still trying to pull the pieces together to make a realistic comparison, but I think a clean sheet approach based on a couple of EV drive axles and one built from an existing PHEV architecture plus a 30-40 kWh battery pack could give much better economy for minimal weight gain - and mean it was completely silent in camp on the typical night, while not needing to be plugged in at any point if it isn't feasible.

    In the worst case, it could run the PHEV's ICE to generate electricity and still be much more efficient and much quieter than a conventional generator (and it would presumably cycle the engine - run for fifteen minutes, then off for a couple hours.)
    Walter
     
  12. miimura

    miimura Active Member

    Joined:
    Aug 21, 2013
    Messages:
    1,239
    Location:
    Los Altos, CA
    Why not just base the bottom end of the RV on a VIA drivetrain system? They already have power export capability that could be used for the appliances inside. Wrightspeed also has a medium duty and heavy duty drivetrains that could power something as big as a diesel pusher RV. Full electric RV is not practical. PHEV makes the most sense.
     
  13. jb2510

    jb2510 Member

    Joined:
    Aug 11, 2013
    Messages:
    7
    Location:
    Savannah, GA
    I thought about getting an RV about year ago but using that much fuel, plus paying for it, doesn't sit well with me. Even with gas prices where they are now I feel it's just too wasteful. It wasn't until we got the MS and did some traveling this summer that I realized how convenient RV Park charging could be. Now topping off a battery for PHEV RV seems like a natural progression of the technology. The Wrightspeed and VIA technology is certainly the way to go but it seems they are still at a proof-of-concept stage. Tesla based tech would be my preference, especially the battery packs.

    I understand that people travel differently but the folks I've spoken with do east coast traveling between Florida and and the Northeast/Canada. They usually travel 250 to 300 highway miles a day and stop at an RV park overnight, maybe staying 1-3 nights. A PHEV would be perfect for this, of course, using the largest Tesla battery pack available. I do like the roll-up solar panel idea in addition to roof-top.
     

Share This Page