[RE-wrenches] Outback FXR Slaves Not Charging With AC

Mon Mar 16 08:11:44 PDT 2026

The manual says to set a subphase master when doing split
phase with serial/parallel stacking, but I guess it's worth a try!

Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956
Florida Certified Electrical Contractor EC13013208

On Mon, Mar 16, 2026 at 11:10 AM Kirk Herander <kirkh at vermont.solar> wrote:

> Will the inverter support just 1 master and 3 slave configuration? This might
> enable all the slaves to charge.
> 
> [data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=3D]
> On Mon, Mar 16, 2026 at 11:01 AM Jason Szumlanski via RE-wrenches
> <re-wrenches at lists.re-wrenches.org [re-wrenches at lists.re-wrenches.org]> wrote:
> 
> > The FXR manual supports the way it was installed and configured. There is an
> > L1 master and an L2 "subphase master." Each of the slaves is assigned to L1
> > or L2.
> > 
> > 
> > And BTW I do have the input mode set to Generator for all four inverters
> > (although the slaves take the setting from their masters anyway).
> > 
> > 
> > Jason 
> > 
> > 
> > 
> > On Mon, Mar 16, 2026 at 10:49 AM Steve Higgins <steve at surrette.com
> > [steve at surrette.com]> wrote:
> > 
> > > Hey Jason... I'll admit it's been awhile since I was with OB.   But from
> > > what I remember you can only have one Master inverter.  
> > > 
> > > 
> > > You can't have a master and slave on each leg.
> > > 
> > > 
> > > The port one inverter needs to be a 1 -2 phase master.  
> > > 
> > > 
> > > The other three should be slave L1 or L2 depending on the phase that they
> > > are connected to.  
> > > 
> > > 
> > > My bet is the charging isn't syncing due to the master/slave setup.  
> > > 
> > > 
> > > Right now they aren't backfeeding due to the generator is syncing the
> > > phases.  I like to call magic stacking.    Eventually when the generator
> > > isn't running you could see enough drift from that 2nd 1-2 phase master
> > > that might cause a backfeed or overcurrent error.  
> > > 
> > > 
> > > 
> > > 
> > > [https://ci3.googleusercontent.com/meips/ADKq_NaBqE16Ig5QKDNqB00Gd4kLkoy8MiGmmTS1sr-ex1o-9pw4syB4LB31QhGnKpbwtT4aZt1G0XPfk4_0pdz9B-LBXxRux739s7bRddJMyN2n7ZnXtK6920pc0w=s0-d-e1-ft#https://storage.googleapis.com/bucket-images-sig/RollsbySurrette.jpg]
> > > Steve Higgins ⋅ Technical Services Manager
> > > t +1.902.597.4020   m +1.206.790.5840
> > > f +1.902.597.8447   e steve at surrette.com [steve at surrette.com]
> > > [https://ci3.googleusercontent.com/meips/ADKq_NZLg7-MWZxFFRL82cgf8A2rT8ddmgk8pJqeLnc8FKZgQkwuW4ZwksC0soR_7_bkUpt14dJV9bTFeEEDztLLM7h0__oEDm4qGPHvr_Bd2fanXlp-9ljoxSYjK6TULp2RMXESyxwlzHba0tjeYA=s0-d-e1-ft#http://cdn3.iconfinder.com/data/icons/free-social-icons/67/facebook_square_gray-24.png][https://ci3.googleusercontent.com/meips/ADKq_NbA6NI5jGTi5vOC4oq8_ofvAeiZG4WZ2kF8_Xgh0Vpf42uAlUaVvjg_zckDYxowQQ7oQNJZ70llI0Y_VB-xYKdA3Y6lLolKpd-rXs8-4nKHOLJMA507y2nFOZHZhIkCRwkOWRgAza1Z_w=s0-d-e1-ft#https://cdn3.iconfinder.com/data/icons/free-social-icons/67/instagram_square-24.png][https://ci3.googleusercontent.com/meips/ADKq_NaKNfUwaBbJt3W1YAgLIblOot3ivDxWZHMRtHArHANpQ8PuNtzwotGr4bMx_sNoAs6xRqolfUoFFmYIDkH6adld48tWd2BnrBEIHx2_Fzvcn6unothJwgkaUpNs2O0p4OxNNYiqRqCqpOFc=s0-d-e1-ft#http://cdn3.iconfinder.com/data/icons/free-social-icons/67/youtube_square_gray-24.png][https://ci3.googleusercontent.com/meips/ADKq_Nbmmi3ObYnpUheVTVKAaPIHxQO9WUd76DHQG398nmIYJ1KIiV9ZNKbPWEMUYOB3MzVkJtQtSwDhVzFYbv1YC9PfgtCjumifOQncEgquMvUj5EqS0_S3gzXJDr51eal6Afs7bQ9hYZHdrkftRA=s0-d-e1-ft#http://cdn3.iconfinder.com/data/icons/free-social-icons/67/linkedin_square_gray-24.png]
> > > 
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> > > 
> > > On Mon, Mar 16, 2026, 7:40 AM Jason Szumlanski via RE-wrenches
> > > <re-wrenches at lists.re-wrenches.org [re-wrenches at lists.re-wrenches.org]>
> > > wrote:
> > > 
> > > > I inherited am off-grid service client with four FXR3048A configured in
> > > > 120/240 split phase with one master and one slave per leg. I believe I
> > > > configured all of the AC input charging parameters correctly, requesting
> > > > max charge rate from each inverter. However, when AC input is present
> > > > (from a generator) the masters will bulk charge, but the slaves do not
> > > > charge at all. The slaves do share the load, but show 0.0kW for
> > > > charging.
> > > > 
> > > > 
> > > > Any ideas?
> > > > 
> > > > 
> > > > Jason Szumlanski 
> > > > Florida Solar Design Group 
> > > > 
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> 
> 
> Kirk Herander / kirkh at vermont.solar [kirkh at vermont.solar]
> 
> Owner|Principal, VT Solar, LLC
> 
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