[RE-wrenches] EG4 GridBOSS Generator Exercise

Wed Apr 8 12:54:24 PDT 2026

Jason

I have a 3D printed nylon case and fully Potted the shelly in it for
outdoor use. One has been operating in full FL sun and rain outdoors with
zero issues.
Pretty easy to make the Shelly 100% long living in the FL weather. See
attached.

On Wed, Apr 8, 2026 at 3:41 PM Jason Szumlanski via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Update:
>
> Thanks to those of you who suggested various AGS relay devices. They all
> seem a bit overkill and costly for simply connecting two wires together once
> a week, but they are all great suggestions nonetheless. I confirmed that a
> little $18 Shelly 1 Gen4 device will do what I need it to do. I'm not sure
> how it will hold up in various environmental conditions, but we will see!
>
> Also, I just heard from my EG4 technical rep. He pointed out that there
> is a generator exercise option for the FlexBOSS inverters, so if the
> two-wire start is connected to the master inverter, it would presumably
> work to exercise the generator; however, there are no SOC start/stop
> parameters available for the inverters when a GridBOSS is connected. I
> suppose if you connect both the GridBOSS and FlexBOSS two-wire start
> terminals in parallel, it might work where each device can fulfill a
> separate function, but I would have to test that out.
>
> Regardless, it's pretty shocking that they missed the exercise function on
> the GridBOSS, which is designed to be a single point of generator
> connection for all inverters and to remotely control generator functions.
> The GridBOSS has been out for a while, too, and it hasn't been fixed.
> They have to know about this.
>
>
> 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 Tue, Apr 7, 2026 at 5:42 PM Jason Szumlanski <
> jason at floridasolardesigngroup.com> wrote:
>
>> Seriously. It shouldn't be this hard. The site I just got burned on is
>> grid-tied, so generator exercise is even more important since it will
>> likely almost never run otherwise.
>>
>> On a good note, Midnite released firmware for their AIO that allows
>> you to put the Gen on the Grid port for off-grid and still use the AGS
>> function, but it is limited. At least there is an exercise cycle and run
>> time, but no amps start and limited voltage start options.
>>
>> EG4 does have manual start/auto off (what they call exercise), and
>> cooldown, but otherwise it's limited to V or SOC start/stop.
>>
>>
>> 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 Tue, Apr 7, 2026 at 4:51 PM jay via RE-wrenches <
>> re-wrenches at lists.re-wrenches.org> wrote:
>>
>>> I really don’t know why AGS has been so hard with all these new inverter
>>> companies.  It is a massive weak point for true offgrid.
>>> I can hear the howls now, but most people want AGS.  Regardless many of
>>> those features below are also useful for manual start applications.
>>>
>>> I mean Trace had all this back in 1995 and nothing has changed in terms
>>> of what we want generator back up to do.
>>>
>>> Is there a AIO available today that have anything close to the list
>>> below?
>>>
>>> 2 and 3 wire start
>>> 24 hr, 2 hr, 15 minute volt/start time
>>> load start/start
>>> quiet time
>>> run time
>>> exercise period/time
>>> voltage input window
>>> hz input window
>>> manual start/stop
>>> manual start/auto shut off
>>> warm up
>>> cool down
>>> pre crank
>>> max crank
>>> post crank
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Apr 7, 2026, at 1:25 PM, Jason Szumlanski via RE-wrenches <
>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>
>>> Here we go again with a manufacturer providing poor and misleading
>>> documentation. The EG4 GridBOSS manual says:
>>>
>>> *The GridBOSS should use start/stop relay 1 in the normally open
>>> connection. Start/stop relay 1 can be controlled manually or by battery
>>> SOC/voltage logic within the EG4® Monitor Center. The generator can also be
>>> configured with warm-up, cool-down, and exercise time.*
>>>
>>> I just learned that there is, in fact, no automatic scheduled generator
>>> exercise feature on the GridBOSS. This is a real problem because many
>>> generator controls disable the onboard exercise function when
>>> remote-start capability is enabled.
>>>
>>> So what is "exercise time" in EG4's world? Apparently, that means you
>>> can set a duration for the generator to run when you MANUALLY start the
>>> generator from the app.
>>>
>>> Hope this saves someone else a big headache, hours of research, and
>>> clueless tech support.
>>>
>>> Any thoughts on a simple external relay in parallel to accomplish this
>>> function? I was thinking about a Shelly connected to a smart load for
>>> power in the GridBOSS. It just needs to be a programmable relay to close on
>>> a schedule. How reliable are Shelly relays for scheduled tasks?
>>>
>>>
>>> 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
>>>
>>>
>>> _______________________________________________
>>>
>>>
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