Grid Tie inverter and ts-45 using the same solar panels

bumper
bumper Registered Users Posts: 14
Is this safe? i see no reason it is unsafeAttachment not found. unless it would
interfere with the tri-star ts-45 operation. thanks

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Grid Tie inverter and ts-45 using the same solar panels

    Won't work.
    The reason why: the input on both the charge controller and the GT inverter is the same; an MPPT device. So they will both try to 'load' the panels to find the ideal point for each, causing the other to have fits trying to find the MPP when the loading keeps changing all the time.
    If you look in the manual for the charge controller it probably says not to hook two controllers to one array (Outback says so).

    The moral is: one charge controller or inverter per array.
  • bumper
    bumper Registered Users Posts: 14
    Re: Grid Tie inverter and ts-45 using the same solar panels

    Thanks for the reply, i guess i will just have to switch between the two operations.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Grid Tie inverter and ts-45 using the same solar panels
    bumper wrote: »
    Is this safe? i see no reason it is unsafe unless it would
    interfere with the tri-star ts-45 operation. thanks

    You cannot effectively parallel two MMPT devices (whether CCs or inverters) off the same set of panels, since their MPP searches will interfere with each other. Whenever one changes its current draw to try to maximize power, the other may react to the changing voltage by changing its set point also. (If the two units are from the same manufacturer and designed to communicate, it may work.)

    Since the Tri-Star is a PWM controller, which is working just on the basis of the battery voltage and current, it will not have a problem. But an MPPT GTI will do its best to maximize its input power based on the relationship between the load it provides and the voltage. It can be confused by the varying voltage from the array as the Tri-Star pulses on and off. I would not recommend it.
    SMA SB 3000, old BP panels.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Grid Tie inverter and ts-45 using the same solar panels
    bumper wrote: »
    Thanks for the reply, i guess i will just have to switch between the two operations.

    You could maintain some flexibility by making the panels switchable in groups rather than all or nothing. Use all three panels to the CC while charging the batteries in Bulk and into the first part of Absorb. Then as the current requirement of the battery goes down, switch the panels one at a time over to the GTI to sell the extra power. The GTI is the more flexible of the two.
    You can either do this manually or build your own controller to automate it.
    SMA SB 3000, old BP panels.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Grid Tie inverter and ts-45 using the same solar panels

    Tristar charge controllers come in both MPPT http://www.solar-electric.com/motr45ampmps.html and PWM http://www.solar-electric.com/trts12vochco.html versions.

    It does not matter. Even if the MPPT function did not get confused you would effectively be take some power for one system and some for the other, effectively dividing up the array.

    Got to say I'm a bit leery of any GTI that only needs 375 Watts on it. What is the point? Are you trying to divert an "unused" portion of array power at peek hours to GT?
    Pretty sure any such wiring would not pass approval from officials.
  • bumper
    bumper Registered Users Posts: 14
    Re: Grid Tie inverter and ts-45 using the same solar panels
    Tristar charge controllers come in both MPPT http://www.solar-electric.com/motr45ampmps.html and PWM http://www.solar-electric.com/trts12vochco.html versions.

    It does not matter. Even if the MPPT function did not get confused you would effectively be take some power for one system and some for the other, effectively dividing up the array.

    Got to say I'm a bit leery of any GTI that only needs 375 Watts on it. What is the point? Are you trying to divert an "unused" portion of array power at peek hours to GT?
    Pretty sure any such wiring would not pass approval from officials.

    There is actually 5 panels at 125 watts each, i just drew 3 for simplicity. but your comment confuses me "Pretty sure any such wiring would not pass approval from officials." what does the number of panels have to do with any inspector?? and the GTI is approved for use anywhere and sense there are GTI running at 200 or so watts
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Grid Tie inverter and ts-45 using the same solar panels
    bumper wrote: »
    There is actually 5 panels at 125 watts each, i just drew 3 for simplicity. but your comment confuses me "Pretty sure any such wiring would not pass approval from officials." what does the number of panels have to do with any inspector?? and the GTI is approved for use anywhere.

    Let's see: 5 * 125 = 625 Watts. What GTI is that, then? A Sunny Boy 700?

    What the AHJ would not like is the PV feeding a combination of charge controller and GTI, not the number of panels. They don't care how many panels you have so long as it all meets code.
  • bumper
    bumper Registered Users Posts: 14
    Re: Grid Tie inverter and ts-45 using the same solar panels
    Let's see: 5 * 125 = 625 Watts. What GTI is that, then? A Sunny Boy 700?

    What the AHJ would not like is the PV feeding a combination of charge controller and GTI, not the number of panels. They don't care how many panels you have so long as it all meets code.

    the gti is 600 watts, where i live is down behind a hill , and the panels are just basically lying on top of my tool shop, so i have never seen
    the output thru a kill-a-watt meter get over 350 watts so the gti is safe for now, if and when i get serious i will build a support and point then accordingly , break the panels up into smaller wattage Gti's and maybe even add sun tracking.
    thanks
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Grid Tie inverter and ts-45 using the same solar panels
    bumper wrote: »
    the gti is 600 watts, where i live is down behind a hill , and the panels are just basically lying on top of my tool shop, so i have never seen
    the output thru a kill-a-watt meter get over 350 watts so the gti is safe for now, if and when i get serious i will build a support and point then accordingly , break the panels up into smaller wattage Gti's and maybe even add sun tracking.
    thanks

    It would be remiss of me not to mention some things regarding this post.
    Output through a Kill-A-Watt meter? That implies this is one of those illegal plug-n-play inverters. An inverter will only output its maximum capacity, no matter how many panels are connected to it.
    Break up panels into smaller Wattage GTI's? Why? Unless the panels have to point in different directions there is no reason to go the 'micro inverter route'.
    Tracking. Lot of money and not necessarily worth it. Usually the $ is better spent on more panels.

    On the whole I don't like the sound of your set-up and worry there may be something unsafe and/or illegal about it.
  • bumper
    bumper Registered Users Posts: 14
    Re: Grid Tie inverter and ts-45 using the same solar panels

    according to my power company ,using this GTI If there is no AC grid detected, the red LED will be on, the inverter will not put out power, this is called “Island Protection”. is safe and legal.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Grid Tie inverter and ts-45 using the same solar panels
    bumper wrote: »
    according to my power company ,using this GTI If there is no AC grid detected, the red LED will be on, the inverter will not put out power, this is called “Island Protection”. is safe and legal.

    Most all GTI's have anti-islanding. That does not mean they are all safe and legal. To fit that description it would have to be a hard-wired install done with permits and inspection as well as the permission and co-operation of the utility. The process is the same regardless of the size of the install, so there isn't much point in doing a small GT system.

    I do not know what you have for equipment or what process you underwent to get it installed. I'm merely stating that based on the posts you've made the system seems questionable to me.
  • fix_it_guy
    fix_it_guy Solar Expert Posts: 26
    Re: Grid Tie inverter and ts-45 using the same solar panels

    If I may just throw something in here... First I don't want to encourage Illegal or dangerous activities but.....

    Make sure any GTI is on it's own dedicated circuit. People always site the anti-islanding is operational, seriously who cares, a lineman is not stupid and will not get juiced when working on ANY line. The real issue with these things is the fact that you can overload your home wiring. If something simple like a microwave or toatser or coffemaker are on the same circuit.... just trust me there is then the possibility of feeding say 15 AMPs from your breaker panel and 15 AMPs from your inverter at the same time sending 30 A of current on a set of 14 Gauge wires. This will cause an overcurrent condition and the breaker won't trip because it is only supplying 15 A which it is rated for. This can cause a fire as the wires overheat.

    Just trust me. If you are going to do this, which I know you are, Make sure it is on it's own dedicated circuit.

    Again I am not endorsing these inverters, I am just giving saftey advice.