Flexboss21 selling back while charging batteries

captjwh · 2026-03-24T02:49:01Z

Apologies if this has been addressed.. if so, please point me to the post. system = GridBoss - FlexBoss21-#1/qty3 280Ah Indoors, FlexBoss21-#2/qty3 280Ah Indoors, FlexBoss21-#3/qty6 280Ah Indoors FB = FAAB-2525 GB = IAAB-1600 Bat = 2.04 later in the year i'll install a victron buss and pool all inverters and all batteries. Gridboss comms loop through all 3 FB21's and back to GridBoss 200A Service as the load - No Smart Loads connected at this time. 22kW solar array - 4 strings. 1 to inv1, 1 to inv2, 2 to inv3 yeah i can't wait to get to the common bus for all...it does make me cry inside.. No errors. Issue... When charging batteries from PV - lets say for example i have 20kW coming in and SOC is 50%-60% across all batteries. Here is the distribution of power 1 kW - House load 17 kW - Battery charging 2 kW - selling back to Grid WHY is it selling to GRID... i want my batteries charged!!! Then i will be very happy to dump to grid. support can't tell me why this is happening at sig solar or at EG4. Said not to be a bug, but more of a problem with firmware logic...... to me this = BUG. Support said that I'm maxing charge to my batteries.. so, i kill grid sell back and my battery charging goes to 19kW - nice try though :D some settings i have AC charge mode set to kick in if for some really wild reason my batteries get down to 5%, stop AC charge at 20% battery type lithium, brand 1 charging SOC, 101% charge limit, current charge limit 250, charge last disabled microgrid disabled - no gene power backup enabled fast zero disable share battery disable parallel settings data sync Enable no forced discharge Unfortunately PV charge priority doesn't have an option to put Load in front of battery charge. If it did.. problem would be solved. When this is enabled house load gets pulled from GRID. I've been told a number of things by 3-4 support people. In the end.. it's super simple use PV to satisfy house load, if there's anything left charge the batteries till each respective inverter's batteries are at 100%, if there's anything left, sell to Grid. I do understand if Inverter #1's batteries get to 100% all remaining PV coming from that single string will go to Grid.. and I'm good with that, but by God the other two inverters better not be giving any power to Grid until their batteries are full! again.. to be fixed with the buss later this year. anyone else have this problem? Help? thanks a lot!

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captjwh

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April 7, 2026 8:23 pm

(@captjwh)

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Joined: 4 months ago

@eg4eric just checking in.. i'm on fab-2727 now.

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EG4 Eric

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(@eg4eric)

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Posts: 1096

April 16, 2026 1:31 pm

Reply to

captjwh

@captjwh
Apologies for the delay. It appears your system is set to AC Charge throughout the entire day. Was this setting applied before or after you started experiencing issues with the inverter exporting power to the grid before the batteries were fully charged?

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Flexboss21 selling back while charging batteries

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