[RE-wrenches] Generator choice for Sunny Island

Fri Jun 16 07:21:31 PDT 2017

Thanks for the good feedback folks!

We are using a Sunny Island setup because we had access to a free Sunny
Island and Sunny Boy being scrapped from another site. Otherwise I was
definitely planning on going with a Outback DC coupled system.

I think the trick here is trying to find a portable generator that has a
two-wire start option. I’m looking through the usual genny suppliers and
nothing has presented itself so far. Anyway, I’ll keep looking and will
check out Chris’ suggestion on the nexus controller and Generac propane
unit as well.

FYI, here is a link to what the portal is like. It’s going in National Park
land by the Golden Gate Bridge so I hope we can pull it together!
http://www.sharedstudios.com/

August

Luminalt

*From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
Behalf Of *Chris Mason
*Sent:* Friday, June 16, 2017 4:56 AM
*To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
*Subject:* Re: [RE-wrenches] Generator choice for Sunny Island

To my limited mind, the whole 120V sunny island setup is a disaster. Why
not install a DC coupled 8KW Outback Radian and solve all your problems.
USe any 240V generator, although finding a 2 wire start gasoline unit may
be hard. I would use a Nexus controller generac propane generator with
propane tank, all mounted on the container. I would never design anything
to use gasoline, it's too dangerous.

On Fri, Jun 16, 2017 at 7:19 AM, Matthew Sirum <matthewsirum at gmail.com>
wrote:

Greetings August,

Great thoughts and comments from Brian!  I would also suggest speaking
with the generator manufacturers' tech/engineering folks regarding the
120VAC configuration and to confirm 2-wire start set up once you have
a brand and model or two in mind.  Generator parts and service
availability in the region of the project may also drive brand
selection.  If you need to maximize the inverter's battery charging
capabilities (depending on battery system charging requirements) you
may end up needing to look at generators in the 7.5 kW to 8.0 kW
capacity range to allow for headroom in generator output loading.

Also; I am curious how you arrived at an AC coupled design for this
project.  I do not know any of the details or specific projects goals
you are working with, but I would potentially consider a DC coupled
system design...  DC/DC charge controller(s) would keep the battery
system charged (and any DC loads operable) even if the Sunny Island
and/or Sunny Boy(s) have a failure or is taken offline.  If most of
the AC loads are 120VAC I would consider keeping the inverter AC
output circuit 120VAC and install a dedicated transformer solely for
the 240VAC load....  Or perhaps consider a 120/240VAC inverter model.
Depending on the overall situation a DC coupled system could be more
resilient.  The dedicated transformer for the 240VAC load could also
potentially help make the system more robust.  Also; I have spoken
with a number of folks who have told me they wish the Sunny Island had
more/better features for generator integration.  I'd like to hear more
from those who have plenty of experience designing and installing
systems with Sunny Islands and generators to learn what the current
thoughts and issues are.

I hope some of these thoughts may be helpful.

Best regards,

----MATT

Matthew Sirum
P.O. Box 1227
Greenfield, MA 01302-1227  USA
phone: +1.413.773.0611
email: MatthewSirum at gmail.com

--------  Original Message Below --------

[RE-wrenches] Generator choice for Sunny Island
August Goers august at luminalt.com
Thu Jun 15 09:02:41 PDT 2017

Hi Wrenches, especially those of you who work on off-grid projects,

We have an upcoming off-grid project where we will be powering a storage
container with electronics in it. The loads are mostly 120 volt but there
is a 240 volt heat pump that might occasionally run. We’re AC coupling the
Sunny Island with a Sunny Boy PV inverter. So, we’ll be installing a
Outback PSX-240 autoformer to bump the Sunny Island’s output from 120 to
240 volt.

We need to select a generator for backup. We need a two-wire electric start
(in order to be controlled by the Sunny Island) and preferably a generator
that is okay just running 120 volt loads since the Sunny Islands input is
only 120 volt. Something in the 3 kVA -7 kVA range should be fine.

Does anyone have experience or ideas about what kind of two-wire start
generator we might select?

Thanks,

August

Luminalt
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-- 

Chris Mason

NABCEP Certified Solar PV Installer™

Solar Design Engineer

Generac Generators Industrial technician

www.cometsolar.com <http://www.cometenergysystems.com>

264.235.5670

869.662.5670

Skype: netconcepts
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