XW+ not load shaving while in sell to grid mode.

here is a description of the system, then the issue.

I have full net metering. I have an AC coupled Solar Edge 4000w inverter (5.2KW DC). I also have a Schinder NW+ 5548 with a context mppt150 charge controller (2.2KW DC) and 20kw of Simphi batteries. there is a Schinder gateway hooked up to the system. The whole house is backed up thought the XW+.  Settings: grid support at 52.5V; low battery cut out 48v; recharge 50.5V.' XW in two stage no float. mppt in 3 stage. float at 54V. all charger settings per the battery manual. The Mppt is new to the system. load shave on at 0A. sell on at 20A.

Issue:
Prior to the new MPPT I had the system set up to load shave, sell enable at 0A. It would zero out the use between the high priced times from my utility (2-7PM M-F). I would on the weekends turn off load shave and manually change from the surplus AC coupled power. With a spare MPPT and some used panels I made a solar pavilion and hopped to automate my battery charging and compensate for my new EV. My goal is to store the solar made in the morning and sell the excess back during the high priced times.

Adding the MPPT seemed to be the easy way to keep the battery charged and sell the extra only between 2-7 pm. When the sun is out and the battery's get full in the morning (float at 54v) the inverter will cover the loads and sell back at 20A. Tidbit: no where in the manual does it call this out but this is a total export limit of AC coupled and inverter supplied power. so if the solar edge is exporting 10A (2400w) the inverter will only export another 10A. this is odd but I can work with that.

The hard part is that it does not always load shave while in grid support mode. So, if the clouds come over and there is a draw on the grid for a few min the sell drops down and the load is not covered. As I understand this to be designed to work, and how I need it to work, is that if the inverter is .5v above recharge and in load shave window the grid draw is 0. Why does sell mode screw this up? Why can't it load shave first, then sell above that draw?  In this system If the DC is cranking out power and the battery's are full it does shave off the load. if the battery's are within about .5-1.0 v of grid support or less it will not shave the load. Once sell is blocked at 7pm it is programed to sell block and load shave for another 3 more hours to deplete the battery below grid support voltage so that the inverter does not buzz all night in grid support mode.

Why is it not load shaving and selling at the same time?
Why will it work at times but not when close to grid support voltage?
How do I get this to work reliably?

any other ideas for me?

With net metering is not a huge deal but I should be able to have a 0 use from 2-7pm and sell everything I can back at 1.5x the normal price :).

Thanks for any advice!

Comments

  • weatherspotterweatherspotter Registered Users Posts: 5
    Here is an example of the energy screen on a day when it was not working correctly.

    MPPT settings,

    Inverter settings:



  • mike95490mike95490 Solar Expert Posts: 9,363 ✭✭✭✭✭
    Looks to my untrained eye, that the Load Shave Amps slider is set to 0

    I'm not gridtie, so I've never dealt with those settings
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • weatherspotterweatherspotter Registered Users Posts: 5
    Load shave means shave off everything over set point Amps so set point at 0 should tell it to try to shave off all load.... and it worked with load shave only.... but not with sell enabled over 0 amp....
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