trace 4024 grid tie

I have trace SW 4024 in grid tie mode w/ C60 & C35 charge controllers. Solar array is presently 1.7KW. Does anyone have suggestion on optimum voltage settings for sell voltage or variance within the charge controls? I appreciate the fact that a MPPT control would give greater performance but PWM is what I have. Have a small battery bank which is simply the buffer between ac and dc.

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: trace 4024 grid tie

    Assuming you have the correctly configures Trace SW inverter for Grid Tied (which I am not sure you have or is legal to install within the last few years)...

    You want the Grid Tied inverter to basically "float" the battery. So, as long as the battery is >26 volts, it should be fine. Obviously, too high will tend to over charge the battery bank--You would be looking at roughly anything over 27-27.6 as the maximum "float" voltage... Check your battery vendor for their float recommendation.

    To properly operate the inverter in GT Sell mode (and not overstress the batteries), you should probably have a minimum of 800 Amp*Hours of Battery Bank at 24 VDC.

    If you have not put a lot of money into the system yet (new install)--the Trace SW line is (as far as I recall--I am not in the business) is long out of any factory support/repairs and most (if not nearly all) of the aftermarket repair shops have dropped repairs too (simply no parts available)--you might wish to look at something current like the XW Hybrid Inverter product line (GT, Off-Grid, and Hybrid mode).

    The Xantrex site has been turned off now (and the redirects are not working for me--at least) as the Solar RE part of their business has been sold to Schneider Electric (whose website needs a lot of work :cry: before being useful).

    Sorry--at this time, I got nothing to link to for you other than our host's website for XW Hybrid Inverters.

    I hope "they" fix this soon...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: trace 4024 grid tie
    BB. wrote: »
    The Xantrex site has been turned off now (and the redirects are not working for me--at least) as the Solar RE part of their business has been sold to Schneider Electric (whose website needs a lot of work :cry: before being useful).

    Sorry--at this time, I got nothing to link to for you other than our host's website for XW Hybrid Inverters.
    This seems to work - http://www.xantrex.com/web/id/1858/docserve.aspx
    Generally, google for "xantrex" and some additional key words would get a working direct link to their site.
    GP
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: trace 4024 grid tie

    Yep, the underlying Xantrex site still appears to be there--but I will be d*mned if I am going to tell users to navigate a site using Google Searches...

    -Bill :grr
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mikeo
    mikeo Solar Expert Posts: 386 ✭✭✭
    Re: trace 4024 grid tie
    I have trace SW 4024 in grid tie mode w/ C60 & C35 charge controllers. Solar array is presently 1.7KW. Does anyone have suggestion on optimum voltage settings for sell voltage or variance within the charge controls

    I have a similar setup with a sw4024 with GTI interface and 1800 watts of panels. I do use an MX60 though for a charge controller. I have my sw4024 float and sell set to 27.6 volts. My Mx60 is set to float at 28.6 which is one volt higher. My average float according to my Trimetric battery monitor is around 28 volts which is what my batterys calls for. It is important to have a battery temp sensor both for the SW4024 and the charge controller for this to work correctly. With cold weather my batteries are floating around 29 volts.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: trace 4024 grid tie

    Depending on what rev software you have will depend on ability to sell or not. Older units will sell, newer units only will sell if grid tie adaptor is used.

    As to charging, set your PV charge controller to battery manufacturer recommended float and absorb levels. Set the SW4024 two tenths of volt lower.

    If you have temp sensor it is important to have both on SW4024 and PV controller. If you have temp sensor for only one unit then do not use temp sensor.

    Whenever PV raises battery voltage above SW float setting the SW will suck off excess and push to AC. This will push power to AC out, and depending on rev of software, will push to grid if ACout loads are not sufficient to consume excess PV power. Same applies to Absorb voltage setting on SW4024.
  • System2
    System2 Posts: 6,290 admin
    Re: trace 4024 grid tie

    Thank you for the feedback regarding my present set-up. you may very well be right regarding usage of the SW inverter and present Certifications. I also appreciated the tech feedback. My present sell voltage has been at 27.2 volts which seems to give my best output from the array. I would have thought that the batteries would be charged well enough to avoid any real damage.
  • mikeo
    mikeo Solar Expert Posts: 386 ✭✭✭
    Re: trace 4024 grid tie
    My present sell voltage has been at 27.2 volts which seems to give my best output from the array. I would have thought that the batteries would be charged well enough to avoid any real damage.

    What float voltage is your charge controller set? Are both SW and charge controller temp compensated? According to the OB MX60 manual they suggest .5 volts difference between Charge controller and inverter float voltages at 24 volts but I find 1 volt seems to work better for me. Maybe it is something special with the MX60 but I find the average float as measured with the Trimetric to be around 28 volts using 27.6 on SW and 28.6 on the MX60. Also in the summer I find it helpful to back off the SW to 27.4 for best performance. I use a forklift battery which requires higher float voltages then most other types of batteries.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: trace 4024 grid tie

    The SW4024 voltage setting is the clamped voltage (unless solar power exceeds 4kW capability of SW). There is some variation as SW tracks variation in AC grid voltage. It will average out the variation to the SW setting.

    28 vdc float on batteries is a bit high but depends on how many hours a day they are actually that high. With SW set at 27.4v the battery will average at that setting.