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

[Kirk Herander]

I've only installed a couple of -4- inverter FX systems, prebuilt by OB,
and both were factory programmed for a single master and 3 slaves.

On Mon, Mar 16, 2026 at 11:12 AM Jason Szumlanski <
jason at floridasolardesigngroup.com> wrote:

> 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.
>>
>> On Mon, Mar 16, 2026 at 11:01 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
>>>> ------------------------------
>>>> CONFIDENTIALITY: The information transmitted herein is intended only
>>>> for the addressee and may contain confidential, proprietary and/or
>>>> privileged material. Any unauthorized review, distribution or other use of
>>>> or the taking of any action in reliance upon this information is
>>>> prohibited. If you receive this email in error, please contact the sender
>>>> and delete or destroy this message and all copies.
>>>> ------------------------------
>>>>
>>>>
>>>>
>>>> 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
>>>>> _______________________________________________
>>>>> List sponsored by Redwood Alliance
>>>>>
>>>>> Pay optional member dues here: http://re-wrenches.org
>>>>>
>>>>> List Address: RE-wrenches at lists.re-wrenches.org
>>>>>
>>>>> Change listserver email address & settings:
>>>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>>>>
>>>>> There are two list archives for searching. When one doesn't work, try
>>>>> the other:
>>>>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
>>>>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>>>>
>>>>> List rules & etiquette:
>>>>> http://www.re-wrenches.org/etiquette.htm
>>>>>
>>>>> Check out or update participant bios:
>>>>> http://www.members.re-wrenches.org
>>>>>
>>>>> _______________________________________________
>>> List sponsored by Redwood Alliance
>>>
>>> Pay optional member dues here: http://re-wrenches.org
>>>
>>> List Address: RE-wrenches at lists.re-wrenches.org
>>>
>>> Change listserver email address & settings:
>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>>
>>> There are two list archives for searching. When one doesn't work, try
>>> the other:
>>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
>>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>>
>>> List rules & etiquette:
>>> http://www.re-wrenches.org/etiquette.htm
>>>
>>> Check out or update participant bios:
>>> http://www.members.re-wrenches.org
>>>
>>>
>>
>> --
>>
>>
>> *Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*
>>
>> *Owner|Principal, VT Solar, LLC*
>>
>> *Celebrating our 35th Anniversary 1991-2026!!*
>>
>> dba Vermont Solar Engineering
>>
>> 802.559.1225
>>
>

-- 


*Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*

*Owner|Principal, VT Solar, LLC*

*Celebrating our 35th Anniversary 1991-2026!!*

dba Vermont Solar Engineering

802.559.1225
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20260316/b1360a9a/attachment.htm>