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  • 1.  EV's for Off Grid

    Posted 09-05-2022 09:02 AM
    I'm wondering if anyone is aware of a system for charging an electric vehicle for us off grid folks? Obviously I could just plug it in to a 120V AC outlet when we have adequate sun but that seems like a pretty inefficient and labor intensive way to go about it. I'm thinking of a something more along the lines of our solar deep well pump that directly converts DC to 3-phase AC for the long trip down the well bore. In the case of EV charging it needn't even be inverted to AC, just the correct voltage DC. The current flow would vary based on the resource but the voltage would remain constant, based on the requirement of the EV battery pack. For our use it wouldn't even need to be a large array, as we only drive once or twice a week. I think what I'm really talking about is a robust, programmable DC/DC converter. I don't think there is any technical barrier but the demand may be too low for anyone to develop the product - at the moment. Does anyone know of such a thing?

    Tracy Dahl

  • 2.  RE: EV's for Off Grid

    Chapter Leader
    Posted 09-06-2022 09:31 AM
    Tracy -
         I also am 'off-grid' and had an issue with just how to charge (re-charge) an EV at home ! I also was frustrated and decided to buy a 'hybrid EV' that could charge the battery while driving ! If I had the funds, I would have purchased a 'PHEV', and when possible, use an EV charger 'on-the-road' ! I understand your position and do not have the answer, although I think there are folks that may be 'able' to put that together, as you have indicated ! Good luck, let me know ! Thanks ...

    Peace -
    John Burke
    Maine Solar Energy Association;  SEADS of Truth, Inc.
    Downeast Alternative Design Solar, Inc.  (DADS, Inc.)
           -  (207) 546-1639;  (516) 669-2442

  • 3.  RE: EV's for Off Grid

    Posted 09-06-2022 09:33 AM
    Hi Tracy,

    I would charge the car using AC (either 120V or 240V) for a couple of reasons:
     - Most EVs have on-board chargers that designed to perfectly take care of the battery regardless of state of charge (SOC) or battery temperature, a DC-DC system would have to be designed to talk to the vehicle battery manage system (BMS) and regulate the charge.
     - Isolated DC-DC converters are about 87% efficient, a little better than the combination of a solar inverter and car battery charger, but not significantly better to warrant all of the work and potential risk to the battery to implement a DC-DC system.
    I would definitely charge during sunlight hours if you can to improve solar system efficiency and reduce wear and tear on your home batteries.


    Brian Jensen

  • 4.  RE: EV's for Off Grid

    Posted 09-06-2022 01:28 PM
    When level 1 (120 volt) or level 2 (240 volt) charging is used, AC goes into the EV.  The battery charger in the EV changes AC to DC to charge the battery.  With level 3 charging DC goes into the EV; this is referred to as fast charging.  Frequent fast charging could shorten the life of the EV battery.  
       Using level 1 (120 volt) charging is gentle on the EV battery, allowing it to have a long life.  This is likely your best option, especially if it is used while the batteries are full and the sun is hitting the PV modules.

    Stu Besnoff
    Alpine Solar Heat and Hot Water, LLC

  • 5.  RE: EV's for Off Grid

    Posted 09-07-2022 09:28 AM
    Aptera is a solar powered EV that can get 40 miles per day parked in the sun. It will be coming out next year (2023) and you can reserve one for $100 refundable. $70 if you use my referral code


    Sono and Lightyear are also solar EV companies that will come out with their solar EVs next year. 

    There's also this goofy thing at https://www.notateslaapp.com/news/872/taking-teslas-off-the-grid-with-innovative-ideas

    Julia Moravcsik

  • 6.  RE: EV's for Off Grid

    Posted 09-07-2022 01:26 PM
    OMG!! ...lol... KISS. Use level one at 1500W and hang a level 2 for time emergencies.
    Put your brain energy to better use.... unless you are just bored...

    william fitch