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Messages - DSinOR

#1
Hey - thanks for the replies!

Mike - If I proceed with a grid-tie, I obviously have to comply with code, etc and pass inspection.  The XW is rated to a max of 60amp output on backup power.  To pass inspection, my subpanel must have a max rating of 60amp.  My main panel is 100 amp.  Therefore I have to get rid of 40.  Plus I have to install a subpanel.  That's what i mean be restrictive.  It restricts me to a certain course of action.  PITA really.  I would much rather have a less automated and less restrictive system that fed backup power to my existing main panel and allowed me to ration power to any destination I choose, much as you already are doing in your off-grid system. 

The point is: it is very possible to have less automation and less restriction in a safe reliable transfer system.  To boot, in my experience, less automation = less cost and increased reliability.

I understand that the market is currently driven by big-dollar customers who prefer total automation.  But i also feel there's a large market out there who would be satisfied with less automation at a lower price point. 

The 240 part is a bummer.  I've read a bit about stacking, but to be honest, I struggle with paying high prices for two inverters just so I can to stack them.  Correct me if I'm mistaken, but 2 outbacks will far exceed the cost of 1 XW?

I didn't know that using the same inverter for both grid-tie and off-grid application was completely out of the question.  That's also a bummer. 

The primary concern from a design and inspection standpoint is to assure safety for both the homeowner and the grid operators.  That's what 'safe transfer' is all about.  Jens suggests that dual service is feasible, but not legal.  If multi-pole switches can be applied to ensure isolation, what other reason exists for prohibiting dual service from an inverter?  My reason for asking is not to be objectionable, but rather because I'm really interesting in learning why or why not. 

Jens - thanks for the suggestions and ideas.  I intend to give them some study as time permits. 
#2
Greetings.  I found your board while searching for "outside the box" ideas for using batteries and inverters in a residential power system.

Check out my drawing. 



I want a solar grid-tie with battery-backup system.  I want to obtain the tax credits, so I'll be using UL Listed components and following code and obtaining permits and inspections. 

I don't like the Xantrex XW solution because it restricts backup power only to a selection of dedicated circuits in a subpanel.  Plus it's all automated.  Plus it's $3500. 

My family uses 50kwh on a normal day.  We can cut that to 10kwh pretty easily.  Therefore I don't need to restrict my backup power to a handful of dedicated circuits.  I want the capability to access backup power on any circuit in my main panel, excepting obvious hogs like water heaters and cookstoves.

In the style of typical grid-tie (no-battery) systems, I'm okay with losing all power when the grid goes down.  In power outages, I'd take this opportunity to turn off computers, UPS's, light switches, and the breakers for cookstove, water heater, and clothes dryer, thereby transforming my 100-amp service household into a 30-amp service household.  The only things left on are fridge, freezer, and water well.  At that point, I could then actuate a DPDT manual transfer switch that isolates me from the grid while simultaneously connecting my backup power sources to my inverter and main panel. 

I think of it as an off-grid system with a grid-tie capability. 

My questions for you guys:
Is this feasible? 
Can it be done in compliance with code?
Is there a synchronizing, auto-shut-off grid-tie inverter on the market that allows a workaround so that it will serve as a basic off-grid type of inverter when I actuate my manual DPDT transfer switch?  Or something equivalent, perhaps an off-grid inverter with add-on synchroniser and auto-shut-off accessories?  Or something totally different? 

I'm not an electrician.  I need ideas on how to bring something like this to fruition in a way that will satisfy my inspector and meet code requirements and use UL Listed components. 

I asked on other boards, but I keep getting the same answer: buy the Xantrex.  I'm hoping for some discussion here. 

Thanks!  By the way, great board!