Installers: Sunny Boy TL-US string sizing tool now available

Using the solar industry’s most advanced residential inverter is now even easier, thanks to the new Quick Design Reference Tool for the Sunny Boy TL-US with Secure Power Supply. Now available for free download, it provides string design and inverter sizing recommendations in a simple, easy-to-use format. Just input basic module criteria found on data sheets a details like design temperature, loading ratio preferences and the AC output voltage.

Based on this information, the Quick Design Reference Tool will calculate the optimum number of strings and modules per string, as well as the ideal inverter loading ratio (DC:AC) and model of Sunny Boy TL-US with Secure Power Supply. This customized assessment can be printed for customer presentations or as a reference during installation.

Download the free Quick Design Reference Tool from the Sunny Boy TL-US with Secure Power Supply product page and start designing!

  1. John G Eyles
    John G Eyles says:

    The Quick Design Reference Tool (spreadsheet) doesn’t cover inverters smaller than the 5kW size. I am trying to decide between a 5.0kW and a 3.8kW model for my system, which has a nominal DC wattage of 4.86kW

  2. Tom
    Tom says:

    I am a newbie and still learning about solar. Question about which inverter to use. Using the SMA Web Design tool, I first used one of the inverters and then switched it for the other inverter. I get all green checks for both systems when inputting all the data. My system will be (40) JA Solar 380w panels using (2) of either the SB7.0-1SP-US-41 or SB7.7 1SP-US-41 inverters for a residence.

    I am reading about the DC to AC ratio which should be around 1.2 but don’t understand it enough. Is it something to be really concerned about.

    Which of the two inverters should I use for my setup?

  3. Peter Talmage
    Peter Talmage says:

    Hi Carl, I’m planning to run 4 strings of 5 solar world 350XL modules through a Sunnyboy raid shutdown box into a Sunnykboy 7.7US inverter. Do you see any issues here ? Thanks.

  4. Peter Talmage
    Peter Talmage says:


    I’m trying to use your string sizing software, but all it downloads is what appears to be an excel spread sheet with some instructions at the top and the word DISCLAIMER in red and a string of red # signs all the way across under it. Could you help as I find these string sizing programs offered by all manufacturers to be very helpful to save lots of design time. Thanks

    Peter Talmage Energy and Design Amherst MA

  5. carl casey
    carl casey says:

    hi, I have 12, 240w Sharp solar panels, for a maximum possible total of 2,880. I have the SMA/Sunpower SB3000TL-US-22 inverter w/ DC Disconnect. is there any difference in efficiency if I place all 12 panels on a single string, or is it more efficient to separate them into more than one string? if its better to separate, what is the recommended string configuration?. e.g., 2 strings of 6 panels per string, 4 strings with 3 panels per string, etc.

  6. Joseph Hacker
    Joseph Hacker says:

    I am installing SMA 5000 us, and need the proper dc string voltage, for proper operation. I have 450 dcv, on one string, and about 350vdc on second string. need proper installation.

  7. mutura
    mutura says:

    Hi Justin,

    In my previous question I managed to use sunny web design,since am using 40pcs of LG 300 modules with 2 sunny boy 6000 where the design indicates I connect two series of 8 modules and 12 modules in series per inverter i.e. 8 on A mpp and 12 on B mpp.My question is do I need to use a dc combiner or I connect the the two series per inverter directly to the inverter.Please provide the right formula for cable sizing,fuse sizing and ground sizing.


  8. mutura
    mutura says:

    I intend to use 40 LG 300w panels(12kwp) using two sb 6000TL,what will be the most efficient strings configuration to use connected to two sunny island 8000 connected to two Hoppecke battery OPzS 2540 of 48v .this is a stand alone system to be connected to a 50KVa generator.
    Kindly advise.

  9. Daniel
    Daniel says:

    Quick question about this design tool. We have a 31 panel (SunPower 327) project coming up. Your tool doesn’t seem to address this number. I’m thinking of the 7700TL with 3 strings of 7 and 2 strings of 5. One tracker would have 2 strings of 7 in parallel with the a 3rd string of 7. The other tracker would have 2 strings of 5. The strings of 7 face east and the strings of 5 face south. Is there a way to determine the appropriateness of this type of design with the 7700TL given the different orientation factors and production considerations.

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