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newbie question, solar system without batterys

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  • newbie question, solar system without batterys

    Greetings, i'm wondering if i can build a solar system without battery's. say i have a 3000 watts of solar panels and a water heater and a 550 watt air-conditioner and a 850 watt air-conditioner. is it not possible to buy a converter that changes the voltage to 110 ac and use the following logic, if solar watts is less than 550 the use the water heater. if solar watts is greater than 550 but less that 850 watts then turn off the water heater and turn on the 550 air-conditioner. if solar watts is greater than 850 but less than 1400 then turn off the 550 watt a/c and turn on the 850 watt a/c. if solar watts is greater than 1400 then turn on the 550 a/c and the 850 a/c. can't something like this be done ?? i understand i'll need some big caps to handle the load of starting the a/c compressors.

  • #2
    seems to me all i really want is a grid tie inverter

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    • #3
      Originally posted by michaelleewebb View Post
      seems to me all i really want is a grid tie inverter
      Yes! As long as you don't expect to have power when the grid is down (unless you get SMA's SPS), that would be the way to go.
      CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

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      • #4
        agreed, no anti-islanding, for safety purposes. so is there any other electrical parts i'm going to need? i'm thinking 10 300 watt panels in 3 strings, one panel i want to keep separate to play with. so 900 watts max for each string. 3 1000 watt grid tie inverters. they don't have to be master slave type inverters because grid tie inverters get their cadence from the grid, but should be of the type mppt ?? is mppt important if your not going to be charging battery's ?? or do mppt type inverters get you more 110 volt watts than pwm ?? a lot of questions. sorry, i feel like i'm almost there.

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        • #5
          Originally posted by michaelleewebb View Post
          agreed, no anti-islanding, for safety purposes. so is there any other electrical parts i'm going to need? i'm thinking 10 300 watt panels in 3 strings, one panel i want to keep separate to play with. so 900 watts max for each string. 3 1000 watt grid tie inverters. they don't have to be master slave type inverters because grid tie inverters get their cadence from the grid, but should be of the type mppt ?? is mppt important if your not going to be charging battery's ?? or do mppt type inverters get you more 110 volt watts than pwm ?? a lot of questions. sorry, i feel like i'm almost there.
          Uh. I do not believe any legal grid tie inverters are only rated 1000 watts. Any that you find will not have a UL listing and due to poor quality they may fail by burning up.

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          • #6
            Originally posted by michaelleewebb View Post
            i'm thinking 10 300 watt panels in 3 strings, one panel i want to keep separate to play with. so 900 watts max for each string. 3 1000 watt grid tie inverters. they don't have to be master slave type inverters because grid tie inverters get their cadence from the grid, but should be of the type mppt ?? is mppt important if your not going to be charging battery's ?? or do mppt type inverters get you more 110 volt watts than pwm ?? a lot of questions. sorry, i feel like i'm almost there.
            Grid tie inverters are MPPT. I'd just put those 9 panels in series (to reduce copper and copper losses, eliminate fuses) with one approved
            3KW inverter, output 240 VAC. Bruce Roe

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            • #7
              good one sun eagle. i need to be aware of what you can buy and whats legal. back to the drawing board. ul listing is required.

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              • #8
                ugh, priced more than i want to pay. i don't think now is the right time to buy (for me). panels are predicted to continue falling and as the volume of UL inverters increases perhaps their price will continue to fall. especially micro inverters. maybe i'll look again in 2018 or 19. thanks everyone, bye.

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                • #9
                  Originally posted by michaelleewebb View Post
                  good one sun eagle. i need to be aware of what you can buy and whats legal. back to the drawing board. ul listing is required.
                  Unfortunately while the requirement of a UL listing is necessary you will end up spending more for that equipment then those cheap off shore type but IMO it is worth the extra expense knowing you are using a quality product.

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