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

[Tyrone Houck]

The slaves will naturally back off first. My first thought would be to
check when the batteries are low enough to accept a full bulk charge.

Reading further through the thread it seem like the port assignment is the
culprit...

Port 1 should be L1 master, port 2- L1 slave, port 7 L2 sub phase master,
port 8 L2 slave.

Sunny Regards,

Tyrone Houck
Oregon Solarworks LLC
CCB #204937 LRT #076
541-787-1366


On Mon, Mar 16, 2026, 7:58 AM Jason Szumlanski via RE-wrenches <
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> 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.
>>
>>
>> *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
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>> On Mon, Mar 16, 2026, 7:40 AM Jason Szumlanski via RE-wrenches <
>> 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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