[RE-wrenches] AGS quiet time
Ray Walters
ray at solarray.com
Sat Apr 11 14:32:18 PDT 2026
All of these issues and more, are why I've tried to avoid AGS, and go
with an educated customer as the gen start system. Its been a losing
battle lately: off grid people these days expect almost no sacrifices in
loads, AGS, zero maintenance, and the system to cost under $15k, because
they bought it all online from EG4.....and it installed itself! The
internet is amazing these days.
Planning? Load profiles? Tilt adjustable racking for winter? More than
24 hours of battery storage? PV charging when the AIO inverter shuts off?
Ray Walters
remote solar
On 4/11/2026 2:33 PM, Chris Sparadeo via RE-wrenches wrote:
> Another nice-to-have feature would be Gen stop based on PV production.
> Customers dislike hearing their generator run to finish a charge
> cycle in the am when the sun is out.
>
> On Sat, Apr 11, 2026 at 1:01 PM Jay via RE-wrenches
> <re-wrenches at lists.re-wrenches.org> wrote:
>
> My thoughts exactly
>
>> On Apr 11, 2026, at 9:35 AM, Jason Szumlanski via RE-wrenches
>> <re-wrenches at lists.re-wrenches.org> wrote:
>>
>>
>> You're making the case for multiple AGS start setpoints. There
>> should be a quiet time override SOC for AGS.
>>
>>
>> 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 Sat, Apr 11, 2026 at 9:10 AM Zeke Yewdall via RE-wrenches
>> <re-wrenches at lists.re-wrenches.org> wrote:
>>
>> A recent thread included Quiet Time in the list of
>> non-included features with newer inverters. And I too have
>> had customers asking for this. But, in many cases, I find
>> that quiet time is not actually a useable feature for many
>> current off grid houses with lithium batteries, and this is why.
>>
>> With lead acid battery banks, we typically designed for the
>> generator to start around 50% SOC. But, occasionally we
>> could discharge down to 20% SOC without damaging the
>> batteries long term. And, typical off grid houses were
>> usually designed with fewer nighttime loads, compared to
>> nowadays. So, if the battery bank hit 50% SOC at 9pm, but
>> quiet times extended till 8am, we still usually had plenty of
>> reserve left to wait till 8am before starting the generator
>> without any additional failures or battery damage.
>>
>> But a lot of current off grid systems with lithium batteries
>> are sizing for a lower days of autonomy (because of the
>> higher cost of lithium batteries, though that's changing
>> now), and deeper regular depth of discharges. Generator start
>> is often set at 20 or 30% SOC instead of 50%. If we are
>> planning for regularly discharging below 50% SOC overnight,
>> which I do commonly see, there's not nearly so much reserve
>> capacity to wait for a generator start. If we hit 20% SOC at
>> 9pm, with a smaller battery bank relative to the load, and a
>> higher nighttime load from more things remaining on all night
>> that we never used to have (routers, internet, heating system
>> controls/pumps/etc), then the chances of us making it till
>> 8am to wait for the generator start is a lot lower -- we risk
>> a BMS shutdown of the battery sometimes betwen 0% and 10%,
>> before 8am, which depending on the particular equipment can
>> be a difficult situation to recover from. Many AIO's will
>> only black start batteries from solar, not generator, and
>> most (though not all) older charge controllers and inverters
>> will not black start batteries from either solar or generator.
>>
>> So, because we are using deeper discharges, using more energy
>> overnight, and waiting longer before a SOC based generator
>> start, we often don't have the option of waiting 4 or 8 hours
>> or such to start the generator. It needs to start very soon
>> after the call for it, or we run into further problems.
>>
>> What would be ideal is a system that looks at SOC before
>> quite times would start, and if it's not sufficient to make
>> it through a typical night because it's been a cloudy day,
>> starts and runs the generator a bit before quite times start,
>> rather than hoping to make it to morning before running it.
>> An experienced off grid owner can do this automatically,
>> topping the batteries off before going into the night if they
>> are too low. But unexperienced owners or ones who just don't
>> watch their battery SOC all the time, will not. Perhaps
>> we'll come up with AI driving controls that watch the typical
>> batery use patterns and look at the weather forecast, and can
>> do this, just like the experienced off grid operator does.
>>
>> Zeke
>>
>>
>> --
>> Zeke Yewdall
>> PV Engineer
>> NABCEP #031508-89
>> zeke at darkforestsolar.com
>> 303-523-3592
>> _______________________________________________
>> 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
>>
> _______________________________________________
> 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
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20260411/b7be37c4/attachment.htm>
More information about the RE-wrenches
mailing list