[RE-wrenches] EG4 GridBOSS Generator Exercise

Wed Apr 8 13:06:12 PDT 2026

Great feedback! I should pot mine because I plan to put it in the generator
control compartment.

On Wed, Apr 8, 2026 at 3:57 PM William Bryce via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> 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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