Hey Judy,
Sorry to take so long to reply to your question. In regards to adding
a battery backup, you should check out my blog post on solar power for
homes:
http://thesolarpowerexpert.com/solar-power-for-homes/
I've got a flow chart/diagram of how to wire it all up. Your idea is a
good one and implementing a battery backup with a grid-tied inverter
is the best way to take financial advantage of recent net metering
laws. It's also handy for when the grid goes down, as you mentioned.
If you are handy with electronics (or know someone else who is) you
should check out the free charge controller:
http://www.freechargecontroller.org
In addition to functioning as a charge controller, it has plenty of
extra I/O to allow you to implement exactly what you want to do in
terms of an economical way to switch your home between battery power
and grid power.
Cheers!
Chris Troutner
http://www.thesolarpowerexpert.com
I've been looking over grid-tied photovoltiac-enphase systems in the 4 to
5
kw range. I'm really taken with the enphase inverters. They look perfect
except for the possibility of the grid going down for long periods.
Is there any economical way to add battery backup in case the grid drops
out? Is there another system that would be better suited for this
possibility?
Essentially The Outback GFX or Xantrax XW system.
All transfer switches built in with all UL and NEC required disconnects
during power outages for linemen safety. No fancy designs, just have a
standard electrician wire them up and you're good to go.
Both Zantrax and Outback have plenty of I/O.
I do believe plans may be free but to build can take time and money.
Sorry,am I wrong to be skeptical?
Or are we just disconnecting manually from the grid and having the Enphase
system run while trying to sell to the generator?
Perhaps I am missing something, it wouldn't be the first time.
Any way, if a problem crops up and your free charge controller overheats and
catches fire, was it UL listed or by some other testing company?
Your insurance company would like to know.
Any way The major companies go to extreme efforts to design and test
equipment so that linemen, consumers and all involved are kept absolutely
safe.
Its worth the money.
And truly, solar rarely saves you money till you have made it past R.O.I.
Companies that I have dealt with that can help you with any questions and
equipment that I would trust with my home are:
http://www.sunelec.com/ ....yes their prices are real and equipment first
rate.
http://www.solar-electric.com/ Good people, fast service, low shipping cost.
http://www.altestore.com/store/ Has everything, little pricier but good
store.
And wholesale solar, affordable solar, Infingy. There are other fine
retailers but these people have done well for me.
They all have information on the tried and true systems and their pluses and
minuses and are happy to talk with customers.
Randy (not an expert, just cautious)