Battery vs no Battery grid tie systems - efficiency [RE-wrenches]

[Nick Lucchese]

<x-flowed>
Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Need a Laptop? Get a Sony Vaio Laptop Free!
http://click.topica.com/caadlVAbz8Qcsbz9JC9a/ProductTestPanel
-------------------------------------------------------------------

  The FX in Grass Valley with the 93 to 95% figures was configured 
with a 48v array to 48v system. Just yesterday I rewired the array in 
a 72v to 48v step down configuration to take advantage of the higher 
max VOC ratings on all the Outback equipment so it should be 
interesting to see if these numbers to change at all. Even if the 
overall production numbers don't change much the benefit of fewer 
strings is certainly an added bonus. The rewire job probably could 
have been done sooner but it seemed like it may have been close on 
some of the clear cool days in January and February. After four years 
all the connections were still solid except a few modules where the 
installer used oversized spade terminals instead of the correct ring 
terminal. Also a good majority of the rubber o-rings between the 
strain relief and jbox had fallen apart leaving a small gap at the 
strain relief. The plastic lock rings that Kyocera supplied for a 
while led to a less than desirable hold on the strain relief. Some of 
the strain reliefs would just pop right off with a quick tug where as 
the metal lock rings wouldn't give at all. But, as with anything the 
installer certainly played a large role on the integrity of the 
strain reliefs hold on the jbox.

  Looking forward to longer days and larger numbers, Nick





>Your free subscription is supported by today's sponsor:
>-------------------------------------------------------------------
>Investigate just about anyone and anything with Web Detective!
>http://click.topica.com/caadlCmbz8Qcsbbdj4Fa/Web Detective
>-------------------------------------------------------------------
>
>Wrenches:
>
>We do not have data for the SWP but we do have data for the FX and old
>SW w/.GTI.
>As you correctly noted the net energy production (generation minus
>standby / battery charging losses) does vary quite a bit.
>Depends on variables like battery type, battery size, battery age,
>inverter charging algorithm, and inverter efficiency.
>
>That being said we have a couple data points compared straight grid tie
>with a Sunny Boy 2500U.
>- SW with GTI in Sacramento - 50 to 60% of straight grid tie.
>- FX in Grass Valley about 93 to 95% of straight grid tie (MX-60 and
>100 Ahr/48 Vdc concord battery bank)
>(Christoper F. Please chime in here if needed)
>- We have recently launched the Sunny Island and are monitoring it at
>the Sacramento site.
>I will provide data as it becomes available.
>
>Best Regards,
>
>John Berdner
>
>
>Does anyone have any real world information on the overall system
>efficiency of a battery based grid tie system, with backup (such as
>using Xantrex SWP inverters), vs straight grid tie, such as the SMA
>inverters?
>
>My calculations show that there "should be" about 25% less total
>conversion efficiency from panel to grid with a battery based system,
>but those are based on some assumptions that might not be correct, such
>as how much the battery efficiency etc affects the overall system, and
>how the inverter determines when the batteries are fully charged.
>
>
>--
>[Non-text portions of this message have been removed]
>
>Your free subscription is supported by today's sponsor:
>-------------------------------------------------------------------
>Need a Laptop? Get a Sony Vaio Laptop Free!
>http://click.topica.com/caadlVAbz8Qcsbbdj4Ff/ProductTestPanel
>-------------------------------------------------------------------
>
>- - - -
>To send a message: RE-wrenches at topica.com
>
>Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read
>
>List rules & etiquette: www.mrsharkey.com/wrenches/etiquette.php
>
>Check out participant bios: www.mrsharkey.com/wrenches/
>
>Hosted by Home Power magazine
>
>Moderator: michael.welch at homepower.com

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Want a laptop? Get an Apple iBook for free! 
http://click.topica.com/caadlVBbz8Qcsbz9JC9f/Amazing Computer 
-------------------------------------------------------------------

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

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

List rules & etiquette: www.mrsharkey.com/wrenches/etiquette.php

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

Hosted by Home Power magazine

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

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>