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  • HappyPants
    Junior Member
    • May 2022
    • 7

    #16
    Thanks for all the advice. Lesson learned is that its a very hot market, the time to scope out facts in the heat of the moment when houses are selling within hours of their listing makes it difficult to make really informed decisions. Its a bummer that the list agent says at the end of the MLS Listing: "DID I MENTION IT COMES WITH PAID SOLAR!!!!

    This was deceptive and dishonest.

    Its one 2.6kW panel, most likely used for 1 Tesla EV.

    Anyhoo, not a big deal, its a sellers market, they have alot of power when houses are going so fast to investment banks.

    Comment

    • chrisski
      Solar Fanatic
      • May 2020
      • 547

      #17
      Originally posted by HappyPants
      @ Mike - Seller says 2 cars are powered by it in addition to the whole house, does that sound incorrect? You say its small output, and I agree based on the kW specs listed on the Tesla site, something doesn't add up here.
      To maintain any reasonable level of comfort, and charge two vehicles that are both driven 20 miles a day, I would say a 2.65 kw system falls well short of what you need.

      I have a 2.55 kw system on my RV, and I can make enough electricity to run a 1800 watt load for about 6 to 8 hours. I have topped out at 16 kWh production in a day. The system you have is only 100 watts bigger, so perhaps 17 kw power a day in my area in April.

      I don't have an EV, but am planning on getting one. My planning numbers are to use 13 amp level 1 charging for an EV. That is 1560 watts per hour and at 3 miles per kWh, that comes out to 4.5 miles of charging per hour. Level 1 charging those vehicles for 40 miles (20 miles each) per day would use 13.3 kWh, leaving 3.7 kWh to run everything else. Those planning numbers may be off a little and are designed for a Nissan Leaf not a Ford Lightning pick up or Riva SUV.

      For an RV with gas heat, gas fridge, and no AC, that extra 3.7 kWh is plenty. It is not plenty when your typical electric bill for a 3500 sq ft house is 1 MW per month.

      Turn any one high wattage appliance on for any length of time, and that does not work. 20 miles per day per vehicle may not be realistic.

      I used to think Air Conditioning was a luxury. Then I moved away from Massachusetts and now think AC a necessity, but heating is a luxury.
      Last edited by chrisski; 05-28-2022, 02:08 PM.

      Comment

      • Ampster
        Solar Fanatic
        • Jun 2017
        • 3649

        #18
        Originally posted by chrisski
        .......
        I don't have an EV, but am planning on getting one. My planning numbers are to use 13 amp level 1 charging for an EV. That is 1560 watts per hour and at 3 miles per kWh, that comes out to 4.5 miles of charging per hour. Level 1 charging those vehicles for 40 miles (20 miles each) per day would use 13.3 kWh, leaving 3.7 kWh to run everything else. Those planning numbers may be off a little and are designed for a Nissan Leaf not a Ford Lightning pick up or Riva SUV..,......mm
        Level 2 charging is more efficient than Level 1 if that matters to you. 89% vs 84% respectively.
        Last edited by Ampster; 05-29-2022, 12:46 AM.
        9 kW solar, 42kWh LFP storage. EV owner since 2012

        Comment

        • chrisski
          Solar Fanatic
          • May 2020
          • 547

          #19
          Originally posted by Ampster
          Level 2 charging is more efficient than Level 1 if that matters to you. 89% vs 84% respectively.
          Is level 2 available with only 1800 watts to the inverter from a 120 volt inverter?

          I did not think level 2 charging was available using a mere 1800 watts from the 120 volt inverter. The two inverters I have are both 120 volt.

          =============================================

          I did not use inverter inefficiencies in my calculations above, so I will change it to:

          My planning numbers are to use 13 amp level 1 charging for an EV from a 120 volt inverter. That is 1560 watts per hour from the inverter with an 85% efficiency and 1835 watts per hour from the batteries and or solar panels' SCC. At 3 miles per kWh, that comes out to 4.68 miles of charging per hour or 8.54 hours per day . Level 1 charging those vehicles for 40 miles (20 miles each) per day would use 15.69 kWh, leaving an 17 kWh system 1.3 kWh to run everything else.

          1.3 kWh is plenty for my RV for most days, but any cold day I desire to use the heater, that could bring my consumption to 2.2 kWh, so that would not be enough power on those freezing winter days.

          Comment

          • Ampster
            Solar Fanatic
            • Jun 2017
            • 3649

            #20
            Originally posted by chrisski

            Is level 2 available with only 1800 watts to the inverter from a 120 volt inverter?
            ......
            No, Level 2 is only available from 240 volt service. The efficiency I quoted was for the onboard charger. You would have to add inverter inefficiency to that.
            9 kW solar, 42kWh LFP storage. EV owner since 2012

            Comment

            • chrisski
              Solar Fanatic
              • May 2020
              • 547

              #21
              Originally posted by Ampster

              No, Level 2 is only available from 240 volt service. The efficiency I quoted was for the onboard charger. You would have to add inverter inefficiency to that.
              What is the lowest amps you can charge your EV with on level 2?

              Comment

              • Ampster
                Solar Fanatic
                • Jun 2017
                • 3649

                #22
                Originally posted by chrisski

                What is the lowest amps you can charge your EV with on level 2?
                I think it depends on the onboard charger. One of my cars lets me set it at 5 Amps. The other one only goes down to 12 Amps. I am sure it probably varies by manufacturer and by the capacity of the onboard charger.

                I suspect the efficiency is related to the fixed overhead of the onboard charger and the lower the kWhs going in the lower the efficiency. There may be efficiencies related to the higher voltage as well but that is just speculation.
                Last edited by Ampster; 05-29-2022, 05:51 PM.
                9 kW solar, 42kWh LFP storage. EV owner since 2012

                Comment

                • chrisski
                  Solar Fanatic
                  • May 2020
                  • 547

                  #23
                  I’ve always assumed the charger inefficiencies were built into the numbers I’m pulling for a Nissan Leaf like 3 miles per kwh. I hope I don’t need to throw in another 11%-15% charging inefficiencies.

                  Comment

                  • Ampster
                    Solar Fanatic
                    • Jun 2017
                    • 3649

                    #24
                    Originally posted by chrisski
                    I’ve always assumed the charger inefficiencies were built into the numbers I’m pulling for a Nissan Leaf like 3 miles per kwh. I hope I don’t need to throw in another 11%-15% charging inefficiencies.
                    I guess it would depend on where the kWhs that are going into your Leaf are measured? I have ways to measure the kWhs going into my charger and presumably the kWhs going into the battery pack but I have never coorelated the two because from the perspective of the EV I think in terms of miles of range added.
                    9 kW solar, 42kWh LFP storage. EV owner since 2012

                    Comment

                    • chrisski
                      Solar Fanatic
                      • May 2020
                      • 547

                      #25
                      I typed a little misleading. I don’t have an EV, but am leaning to get a Nissan Leaf.

                      Comment

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