BVH: Pismo Beach LiFePO4 hybrid system questions

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  • BVHBVH Registered Users Posts: 2
    edited June 2020 #2
    I'm thinking of building a whole house (less AC and conventional elect over) battery backup system using my 20KWh, A123 brand LiFeP04 pack and an XW Pro.  I don't have nor plan to add a solar generation system but do have a 5KW generator that I probably won't use but could.  Since my packs are permanently configured as 13Serial, my 75% Depth of Discharge Voltage is at about 40 Volts.  I see the specs for the XW indicate 42 Volts as the default LBCO but that in the advanced settings, it can be set as low as 36 Volts.  41 Volts would be my sweet spot.  Can someone verify that the inverter will work reliably without alarm or cutoff down to 41 Volts?  If so, is there a reduction in output at the lower Voltages?

    All of the lithium batteries I deal with use the CC/CV, Constant Current/Constant voltage charging algorithm.  I'm trying to equate the XW Pro Lithium battery options settings to the CC/CV algorithm.  CC/CV requires setting only 3 parameters - the charge termination Voltage, max charging current plus a termination point/current - typically pack Ah capacity divided by 10.  Is this algorithm represented in the Lithium battery bulk charging and absorption charging fields?

    Other inverters, the magnum MS4448PAE for example, are de-rated if both 120VAC and 240VAC Voltages are available.  I don't quite understand "split phase" but this seems to be the reason.  Is the Pro capable of full rated output under all normal operating conditions?

    What specific input is required for the XW?  I see posts saying Single Phase, 120/240, 3-wire and 240 Single Phase.  I have 2 legs of 120VAC terminating in the panel and using one obviously yields 120 VAC and using them both yields the 240 VAC.  The 240 VAC equipment I have uses both legs and a ground, no neutral.


  • Dave AngeliniDave Angelini Solar Expert Posts: 6,147 ✭✭✭✭✭
    North America is split phase. Are you here?     XWP is also 230vac if your not here. Where are you?
    download the manual
    https://solar.schneider-electric.com/product/conext-xw-pro-na-solar-hybrid-inverter/
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • HorseflyHorsefly Registered Users Posts: 434 ✭✭✭✭
    North America is split phase. Are you here?     XWP is also 230vac if your not here. Where are you?
    download the manual
    https://solar.schneider-electric.com/product/conext-xw-pro-na-solar-hybrid-inverter/
    @Dave Angelini - Looks like he has said he is 120/240 split-phase already.  
    BVH said:
    I have 2 legs of 120VAC terminating in the panel and using one obviously yields 120 VAC and using them both yields the 240 VAC.  The 240 VAC equipment I have uses both legs and a ground, no neutral.


    Off-grid cabin: 6 x Canadian Solar CSK-280M PV panels, Schneider XW-MPPT60-150 Charge Controller, Schneider CSW4024 Inverter/Charger, Schneider SCP, 8S (25.6V), 230Ah Eve LiFePO4 battery in a custom insulated and heated case.
  • BB.BB. Super Moderators, Administrators Posts: 32,639 admin
    BVH is probably in the Los Angeles area... But that may not be where the new house is being built.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BVHBVH Registered Users Posts: 2
    I'm in Pismo Beach, CA - Pacific Gas & Electric utility.  The battery modules (I have 4) are arranged in 26S/3P so 85.8V nominal which I will electrically split to 13S/3P.  Each cell is 20 Ah and rated at 3C continuous so each split module will provide 42.9V/120 Ah total capacity X's 4 in Parallel = 42.9V/480 Ah.  So at the full 8000 Watt rated output, the battery would be working at about .4C, coasting along, not including any misc losses/overhead.  I would never have a need for 8KW and estimate my power outage load to be a max of about 2 to 3KW.  My furnace and frige are both DC inverter, soft start devices so no significant surges with them.  Frige runs steady at about 100 Watts and the furnace, at about 550 Watts.  The highest load device is the microwave which is built as part of the electric oven and it consumes 2100 Watts, I'm guessing at 240VAC.  Before I knew the microwave load, I thought the SW would fit the bill but I don't like to be close to rated output.  I've read and re-read the manual but just wanted some real world experience confirmations on a few items.    I've called a couple Solar installers but no one seems to want to install anything other than their regular equipment - Tesla stuff.  I'll try contacting Schneider to see if there's any local installers.  Thank you all for your input.
  • BB.BB. Super Moderators, Administrators Posts: 32,639 admin
    edited June 2020 #7
    BVH, welcome to the forum--by the way.

    I have split your questions into your own discussion (thread). It makes it much easier to keep the questions and answers focused on your system.

    Also, have you looked into conservation? Hybrid/off grid battery based solar power tends to be much more expensive than utility power.

    Grid Tied systems can be very cost effective--But you do not have any sort of backup power if the utility connection fails. And you would need battery and/or backup genset if you have utilty power loss.

    Take care,
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,147 ✭✭✭✭✭
    You sound like you could do this yourself. Drop me an email. I am on the Schneider installer list but I am a bit different in my support of DIY.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

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