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

[Jason Szumlanski]

Yes, this is how they are configured. I may have misstated the port
configuration previously.

I agree - I think this is a matter of needing to discharge the batteries a
bit deeper to get them all to wake up and charge simultaneously.


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, 11:17 AM Tyrone Houck via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> 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
>>>> _______________________________________________
>>>> List sponsored by Redwood Alliance
>>>>
>>>>
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