any software for system design?
I am looking for both grid tie and gridtie w?battery backup
I have read PV design manual by SEI 2nd ed, v2.2, 1998, but it seems oriented more towards off grid folks.

A solar system is just a collection of parts , most of which are UL approved , there is nothing a homeowner can do with this portion of the system

From a "design" point of view, all you really need to understand is how things interconnect

Since this is wire, all that is needed is to make sure you minimize loses

Home power has a simple , free excel spread sheet , you enter in the length of wire , the current and voltage of the source (PV panels) and it will give you the loss in watts/volts/amps and percentage

Design for .5% loss and you will never have problems ... wire is ALWAYS the cheapest part of a PV system

Gridtie is simple ... solar panels feed inverter which feeds grid...

IMHO, the software out there does nothing that one can't do in 10 minutes with the wire spread sheet and PVwatts web site for solar isonalation data...

If there are specific question you need answered, post them here and I will do my best to guide you!

grounding.
I don't understand grounding.

the schematics look simple, I hate the idea of messing up and becoming a crispy critter.
I also understand why you don't carry a 9v battery and either keys or coins in the same pocket

are grounds and neutral the same thing?

when i look at schematics like on OutbackPower it looks like neg and grounds are tied together unless i am reading it wrong. electrons come in 1 wire and go out the other. correct?

http://www.outbackpower.com/pdfs_wiring ... m48vGT.pdf

i understand wire size and distance loss. I want my system to max out almost that MX60 and a GVFX3648 when i get the FX (system building a piece at a time)
i got the wire size spread sheets

That is a good diagram ... if you look at the details , you will notice that the netural and ground are bonded at the AC service , which is correct. All the connetions to the MX60's , Inverters and solar panels are to the cases and frames for SAFTEY !!.

There is a GFI breaker between the negative leg of the PV system and earth ground that bonds the two , but it is only to detect a fault (current flowing from PV- to ground) , just the opposite of what your thinking. If current is sensed , the GFI trips and being phyically connected to the DC Mains breaker , will open the array connections.

Earth Ground is ALWAY for saftey , NEVER for carrying current

snip
----------------
There is a GFI breaker between the negative leg of the PV system and earth ground that bonds the two , but it is only to detect a fault (current flowing from PV- to ground) , just the opposite of what your thinking. If current is sensed , the GFI trips and being phyically connected to the DC Mains breaker , will open the array connections
-------------
snip
----------------------

ah, so, ground and neutral are tied together sorta with a GFI between them which is a very fast blo fuse so they are connected but not really.

I am also rethinking totally maxing out the GVFX3648 after reading more of the wrenches where it is pointed out that runing anything flat out, 100% rather than cruising at 80% may work but may not be conducive to long life of system parts.

I think I need to get a mop and go on my roof and see if I get more output that way, and maybe a gallon of Rain-X.

I am also going to call Louis in the early AM monday
I really wish Maryland had better incentives. (15% tax credit up to $2,000)

I somewhat disagree with the wrenches who dislike up front incentives from postings i have read. without them I would never have made the jump and the payback on my system is >20years. I suspect there would also be a lot fewer wrenches without incentive$.
I also have been LOOKING and LOOKING on my roof for a combiner box for my 8, 324v strings and I am beginning to suspect it doesn't exist.
I want to move 2 or 3 of the strings to another roof but am having to do a by guess and by golly of how the panels are hooked together and 324v is a little dicey diddling with so I am trying to get up to speed where i am weak (everywhere except theory and a lot there too)

The Outback PSPV combiner can be had with fuse holders and KLKD fuses rated for 600vDC. I think you can only fit 7 fuses in one combienr so it may require 2 combiners. This would probably make for less wires strung around anyway.

I suggest you get some books on electricity and study them until you are familiar with grounding therory and practice before you proceed with your system. You should know the difference between grounded conductor, equipment grounding conductor, grounding electrode conductor, etc.

The DC Ground Fault Protector (GFP) Henry referred to is solar specific and mostly for fire protection. It's not the same as the common GFCI in your house.

Brad

Here's a couple of links to NEC related stuff that I think are interesting:

http://www.mikeholt.com/cgi-bin/codefor ... matebb.cgi

http://www.selfhelpforums.com/

http://www.nmsu.edu/%7Etdi/Photovoltaic ... -Stds.html

have fun!