[RE-wrenches] Convert Grid Tie SW4048 to Backup System; Add New Inverter, AC Coupled

[maverick at mavericksolar.com]

Dick,

What are the customers goals? Battery backup works, but requires knowledge of the customer's expectations (energy, power and flexibility). What is the budget for the upgrades. Do they want more solar? They don't want battery maintenance, will they want generator maintenance?

Ask these questions and offer two or three routes, grid tie only, existing inverter with refresh or new inverters, AGM Batteries, 2kw PV add on, etc. We have done all three answers to the same question, but all were directed by the customers wishes.

Thank you,

Maverick


Maverick Brown
BSEET, NABCEP Certified Solar PV Installer ®
President & CEO
Maverick Solar Enterprises, Inc.
Office:     512-919-4493
Cell:        512-460-9825

Sent from my HondaJet!

On Nov 17, 2011, at 6:03 PM, Richard.L.Ratico at VALLEY.NET (Richard L Ratico) wrote:

> Hi Wrenches,
> 
> This is a repost. No replies the first time, so I'm trying one last time.
> 
> I may be "adopting" an eleven year old, Y2K, grid tie with battery back-up
> system. It consists of 12 - Astro-Power 120 modules, installed in 2000, 12 -
> Evergreen  EC-110 modules installed in 2004, only one MX60, which controls BOTH
> sub-arrays, one SW4048 in SELL mode through a dedicated load sub-panel.
> Existing, seven year old battery is shot (8-Trojan L-16). Initial bank of
> unknown batteries was replaced after only four years.
> 
> Recent long, nearby, utility outages have the client requesting a proposal to
> include a new back-up generator and to restore the system selling to the grid.
> Client may decide go straight grid tie to eliminate the batteries. They have
> found the maintenance to be a hassle.
> 
> My thoughts so far: 
> 
> 1)To take advantage of most of the existing hardware, I wonder if it makes sense
> to try to improve the system efficiency by relegating the SW to a manual back-up
> mode only, where, say, by means of a timer controlling grid availability through
> AC1, it would only charge a smaller battery bank once a week. The battery bank
> would be small,
> a single string of either, sealed gel units or T-105s with the new Trojan
> watering system. 
> 2) Provide new grid-tie inverter/s (appropriate string type or Enphase 190s) to
> handle the net metering. 
> 3) Provide a way to AC couple the new inverter/s to the SW in the event of an
> outage.
> 4) Provide a new Honda 3000 inverter type generator connected to AC2 in the SW.
> 5)Provide a way to lockout the grid tie inverter/s when the generator is
> operating.
> 
> Any thoughts or suggestions would be greatly appreciated.
> 
> Thanks in advance, 
> 
> Dick Ratico
> Solarwind Electric
> Bradford, VT
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