[RE-wrenches] EG4 GridBOSS Generator Exercise

[Jason Szumlanski]

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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