Sunny Island Battery Monitoring [RE-wrenches]

[Jeff Clearwater]

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Hi Esteemed Colleagues,

I'm installing an AC "mini-grid" Sunny Island system and wondering if 
I need more battery monitoring than  the Sunny Islands' metering.

Apparently the SI uses a pretty sophisticated algorithm for 
determining State of Charge (SOC).  However it appears to be only a 
smart current dependent voltage monitor - not sure if it's really a 
amphour or KWH meter.  The user meters do not offer a percent state 
of charge reading - only 4 status modes (Normal, Warning, Low, 
Critical).  However the installer set points due include percent SOC 
points for generator start, load shedding and system shutdown.  Seems 
like if the SOC monitoring is sophisticated enough to start a gen at 
30% that they would also offer that info to the user - but they don't.

So does anyone have experience with an off-grid Sunny Island system 
and are you happy with the SOC monitoring in the Sunny Island?  Or do 
you recommend adding a tri-metric or equivalent (or better)?

My concern - as in all off-grid systems - is the metering not 
matching what's really happening in the batteries.

Then again with a tri-metric it could just be more confusing - since 
they are not exactly in sync easily themselves.  And then what would 
you tell the customer to do anyway - override the SI settings? 
Probably not.

Any insight from those that have been there would be appreciated.

Thanks!

Jeff C.
-- 
~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design
Sustainable Energy & Water Solutions for Home & Village
http://www.villagepower.com
gosolar at villagepower.com
NABCEP (tm) Certified Solar PV Installer

530-470-9166
877-SOLARVillage
877-765-2784
72 Baker Rd.
Shutesbury, MA 01072
425 Nimrod St.
Nevada City, CA 95959
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