need advice please

[JudyS]

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?

 

[m II]

"JudyS" wrote in message
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?


--

Co-gen circuits, typically, do not have facilities for a battery storage
system. An automatic disconnect and transfer system is also required for
this.

If you go decent batteries they will cost you more than the energy would
cost from the grid for the rest of your life.



mike

 

[Norman Peelman]

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?

The ratio of the number of brown/black outs to the number of
batteries/maintenance needed is severely lopsided. Batteries need
replacing and are very expensive.

 

[Randy]

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?

Welcome to the Group!
Perhaps you might consider the Outback GFXor Zantrax XW grid intertie
inverters with a small battery bank to keep the power on when an outage
occurs.
My Outback FX2524T will run on two Wal-Mart RV deep cycles for $84.00 a
piece. As long as the sun shines, you will be able to use the solar you have
installed when the power is down. But after sundown, the batteries would
take care of lighting at best till the grid is restored. More battery
reserve does equal more cost and bother (I like to be bothered).
A nice compromise would be to add a built in generator that either the
Outback or Zantrax can control, might work for you, running only to recharge
the batteries as needed till sunrise.
Or as the other gentleman said a generator would work fine with your
Enphase, it would just run the whole time the grid is down while your solar
panels twiddle their thumbs in the sun (pick a quiet one please.)
Otherwise maybe just hooking a UPS up to your critical appliances might be
sufficient.
I have heard from others that had grid tie only systems purchased a battery
charger/ cheap inverter and battery for emergency use. Just size the battery
and inverter to your load and usage (with extra to spare).
Much of this depends on your load needs, reliability of the grid in your
locality and the amount of money in your purse.
I live in an Ice storm prone area so for me, lots of backup makes sense.
Hope this helps.
Randy

 

[Randy]

Welcome to the Group!
Perhaps you might consider the Outback GFXor Zantrax XW grid intertie
inverters with a small battery bank to keep the power on when an outage
occurs.
My Outback FX2524T will run on two Wal-Mart RV deep cycles for $84.00 a
piece. As long as the sun shines, you will be able to use the solar you
have installed when the power is down. But after sundown, the batteries
would take care of lighting at best till the grid is restored. More
battery reserve does equal more cost and bother (I like to be bothered).
A nice compromise would be to add a built in generator that either the
Outback or Zantrax can control, might work for you, running only to
recharge the batteries as needed till sunrise.
Or as the other gentleman said a generator would work fine with your
Enphase, it would just run the whole time the grid is down while your
solar panels twiddle their thumbs in the sun (pick a quiet one please.)
Otherwise maybe just hooking a UPS up to your critical appliances might be
sufficient.
I have heard from others that had grid tie only systems purchased a
battery charger/ cheap inverter and battery for emergency use. Just size
the battery and inverter to your load and usage (with extra to spare).
Much of this depends on your load needs, reliability of the grid in your
locality and the amount of money in your purse.
I live in an Ice storm prone area so for me, lots of backup makes sense.
Hope this helps.
Randy

Out of curiosity i did a little math.
To get close to 4000 Watts a person would have to buy about 21 Enphase
inverters (perhaps 22.)
At Northern Arizona Wind and Sun they cost $227.50 a piece for a cost
without shipping: $4777.50
They list a Xantrex GT Series 4000 Watt Grid Tie Inverter for $2542.50
Yes you would need a combiner box and a few other details but I believe
the enphase would be more economical in a smaller system.
Hope this helps
Randy

 

[Randy]

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)