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  • chargemyleaf
    Junior Member
    • Apr 2023
    • 1

    Minimum System to Charge Car During Daylight

    I want to install panels solely to charge my car during daylight. Can I do this without a battery? I'm thinking I should be able to run the panels to a charge controller & inverter with a 110 or 220 outlet. I would then plug my 110 charging brick into the 110 outlet (and eventually to a 220 charger if this works). Am I correct? Has anyone tried this?, please let me know your opinion/suggestions. thanks!
  • Ampster
    Solar Fanatic
    • Jun 2017
    • 3650

    #2
    Depending on your vehicle and the EVSE either one of them may not be able to handle the changing current as the insolation changes during the day. Spending a few bucks more on a GT inverrter with zero export capability might be a better payback. That way the solar could offset your household loads when not charging and that savings could be applioed toward the ocassional use of the grid to compensate for the variation noted above. A more elegant solution would be an Emporia Energy Monitor and their EVSE that can be programmed to vary current based on excess solar. That is what I use but I also have a substantial Grid Tied system with a Net Energy Metering arrangement with my utility. My rates vary from $025 per kWh to $0.55 per kWh so there is some arbitrage value with that rate differential.
    9 kW solar, 42kWh LFP storage. EV owner since 2012

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    • solardreamer
      Solar Fanatic
      • May 2015
      • 446

      #3
      Battery-less capable inverters (e.g. MPP LVX-6048) are readily available. So, you just need to have enough PV panels to generate a minimum of 720W (6A@120Vac) charge EV.

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      • Ampster
        Solar Fanatic
        • Jun 2017
        • 3650

        #4
        Originally posted by SusanMic

        Isn't it just a distributed solar system?
        Yes
        9 kW solar, 42kWh LFP storage. EV owner since 2012

        Comment

        • jflorey2
          Solar Fanatic
          • Aug 2015
          • 2331

          #5
          Originally posted by chargemyleaf
          I want to install panels solely to charge my car during daylight. Can I do this without a battery?
          Yes. Easy way is to install a grid tie system that will cover your charging use.

          However I am getting the sense that you don't want to do that.

          I'm thinking I should be able to run the panels to a charge controller & inverter with a 110 or 220 outlet. I would then plug my 110 charging brick into the 110 outlet (and eventually to a 220 charger if this works).
          Not . . . really. If you connect solar directly to an inverter, it will have a lot of trouble starting up, since the starting surge will collapse the voltage. You could get around that by drastically oversizing the solar array (we are talking 4 to 1) so the voltage is low impedance enough to start the inverter. But even then you'll only be able to charge during the middle of the day, and any clouds will cause you to LVD the inverter. So you will get a tiny percentage of the total power available.

          If you want to do this independently of a grid, the only thing that really makes sense is to charge a battery then run off that. That gives you insulation from clouds and eliminates the problem of startup surges. Going this route you'd start the charge in the morning, the battery will discharge, the inverter will LVD, the battery will charge, and then it will start charging again. This will continue until solar power is sufficient to support 100% of the load, at which point it will charge continuously.

          The smaller the battery, the faster it will cycle on and off. You could even do this with an ultracapacitor if you were so inclined.

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