Sunny Island Retrofit [RE-wrenches]

[Drake Chamberlin]

<x-flowed>

August,

I'd recommend using a transfer switch that would keep the critical 
loads panel on the grid, until the grid goes down.  That way the 
critical loads aren't limited by the settings on the SI when grid is 
available.  We are looking at a Briggs and Stratton transfer switch 
for $700 + change.

For a device that will show when the grid goes down, you can set up a 
relay, where the N/C contacts are kept open by a grid connection to 
the coil, when the grid is up.  When the grid fails, the N/C contact 
closes, and a light goes on.  The contacts are fed by the protected 
loads source, so power is always available.

How much power can you run through your Outback auto 
transformer?  The ones I've used only allow 25 amps at 120 V, or 3000 
watts.  If most of the loads can run straight from the inverter, 
bypassing the autotransformer, you might be ok.  A second SI might 
not be a bad idea.

Drake



At 09:09 AM 11/8/2007, you wrote:


>Wrenches -
>
>I'm looking for help in figuring out a dilemma for a Sunny Island
>grid-connected system with battery backup.
>
>We are upgrading an old Trace grid-connected battery backup system to a new
>Sunny Island based system. We just fired up the Sunny Island 5048U yesderday
>along with a SB 7000US and and SB 4000US (attached to a 9 kW PV array).
>Everything went well and I'm pleased with the general operation; the new
>Sunny Island has a very intuitive interface. We're using an IOTA transfer
>switch to allow the Sunny Boys to bypass the Sunny Island and Outback X240
>autoformer to reduce losses.
>
>The problem is that the client has a huge quantity of critical loads. I
>didn't realize this at first. Most of them are 120 Volt but a few are 240
>Volt. There are four critical loads sub panels and it seems like 80% of the
>day to day loads are connected though these critical panels. Another
>contractor installed these years ago so we didn't have any control over this
>portion of the design. It's a bit crazy. The sunny island operates such that
>all of the critical loads run through the Sunny Island and Outback
>autoformer. If the Sunny Island and/or autoformer fail then the critical
>panels will also shut down. I'm considering recommending adding a second
>Sunny Island which will eliminate the autoformer and add an additional 5000
>Watts of critical load ability. Secondly, I'd like to add a transfer switch
>to bypass the Sunny Islands incase they fail.
>
>We've warned the customer that their critical loads can never exceed 5000
>Watts and that during a power outage they will drastically need to reduce
>their usage. A point that came up, however, is that they probably won't even
>know if the power does go down. The Sunny Island switches over to battery
>backup completely seamlessly.
>
>My questions:
>
>1. Does anyone have experience and or recommendations about a better way to
>setup this system?
>
>2. Does anyone have experience with the reliability of the above mentioned
>products?
>
>3. Does anyone have suggestions for notifying the customer if/when the power
>goes down so that they can start conserving?
>
>Any other comments are welcome.
>
>Thanks, August
>
>August Goers
>VP, Engineering
>NABCEP Certified PV Installer R
>
>Luminalt Energy Corporation
>Office:  (415) 564-7652
>Mobile: (415) 559-1525
>www.luminalt.com
>august at luminalt.com
>
>
>- - - -
>Hosted by Home Power magazine
>
>To send a message: RE-wrenches at topica.com
>
>Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read
>
>List rules & how to change your email address: 
>www.mrsharkey.com/wrenches/etiquette.php
>
>Check out participant bios: www.mrsharkey.com/wrenches/
>
>Moderator: michael.welch at homepower.com
>
>
>
>
>
>--
>No virus found in this incoming message.
>Checked by AVG Free Edition.
>Version: 7.5.503 / Virus Database: 269.15.25/1118 - Release Date: 
>11/8/2007 9:29 AM


- - - -
Hosted by Home Power magazine

To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at re-wrenches.org

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: re-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------



</x-flowed>