SolarEdge 10k HD Wave - Grid Tie - want to set up emergency solar backup option in case of outage

dcbourdcbour Registered Users Posts: 2
To start with, I'll begin to say I'm new to all of this.  Just put solar in this past December and didn't realize at the time that when power goes out, the inverter shuts down.

Looking to set up some type of backup should power go out - House typically runs between 2 - 3kw at any given time, if electric vehicles plugged in either another 3.4kW or 7.7k depending on which vehicle plugged in.  I can control via web interface the power available to the vehicle charger.  Given the house has a single 240 8gauge that runs from one side of the house (panel) to other side (garage where space to mount inverter, batteries, etc) in finished basement, wondered about something like Aims 24v 4kW pure sine inverter, a minimal set of batteries to run inverter to handle 6kW (for startup surge of ac, etc) at 24v, switch from input on inverter to output should power go out so can run over same wire across the house, a simple 120v charger to keep batteries running since can't have input on same line as output on inverter according to the Aims user guide.

When power goes out, manually shut down house utility breaker, switch the inverter switch from input to output and have it backfeed the house, the solar should come back up in 15m providing adequate power on most days to run most of the house, as well as 2/3 the time, able to support charging the vehicles too.  

I know there are issues with back feeding - thinking maybe get a manual transfer switch instead - will manually throw that when power fails.  Most of the transfer switches want to set up subpanels - trying to find option to take whole house but haven't found any at 200amp input - the house power input.  

My other concern is what happens in the case of SolarEdge inverter given it puts 400+ volts dc down to inverter via their optimizers at each panel, should the load be less than power generated, do they "discard" the excess like most other inverters or do I need a dump load.

Given this is for that rare case when power goes out for extended period, don't want to spend a ton on it but would love to have the basics covered if it means manually shutting down breakers and choosing the minimum choice of what is on/off via the breaker panel itself.  

I'm in the city on a reasonable decent grid which has had growth problems a few years ago resulting in frying pool pumps (2), refrigerator, and a few ups's already.  The past two years have been not bad, with brownouts reported weekly by my ups and  summer outages a couple seconds to couple minutes averaging every other week.  Other seasons have been fine with the last outage lasting several seconds long this past November.  To date, haven't had an outage over an hour in the past 10 yrs and even the major 2003 Northern Eastern US/Eastern Canada outage was back online in about 8 hrs.  That's not to say it won't happen hence me wanting an option.

Talked to 2 electricians locally and since my power configuration more complex than usual and they didn't have any feedback or suggestions for me.  I've got a Generlink (direct "connector" that sits between the meter and the meter mount at the side of the house to plug generator in to house directly) so I have switch that allows either solar or generator.  Inspector said was the first he'd seen of it when I put in the solar.  

I know I have the generator but want a solar option should the outage extend beyond a couple days - my gas supply I have available today.

Thoughts, comments please.  

Comments

  • DanS26DanS26 Solar Expert Posts: 255 ✭✭✭
    "To date, haven't had an outage over an hour in the past 10 yrs"


    .......and you want to spent up to $20k for a battery based backup system......sorry......does not compute......
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring with PVOutput.org
  • dcbourdcbour Registered Users Posts: 2
    That's my point, don't want to drop 20k for a full battery backup solution.
    If I look at my community's emergency preparedness documentation, one of their top 5 items is an extended power outage hence I'd like to be prepared for that.  Given I've got the potential, there has to be a cost effective (ie, less than $1000 max $2000) way to keep some power up and available for at least part of the day.  
    I also run a home based computer business with servers that I'd like to keep running as well as the infrastructure which currently have about 3 hrs of run time now as well as the rest of the house would like to have power, even if only for part of the day.  I've got what I need to boost the ups's to 12 hrs now, just haven't taken the time to put that in place.  
    Having the solar and since can't sell it back to the grid, would like some type of option to get the solar back running after the power goes down to benefit me and would let me charge the server ups's back up as well . 
    So back to my original question, any thoughts, comments on my ideas?
  • DanS26DanS26 Solar Expert Posts: 255 ✭✭✭
    Convert your generator to LP...then bury a 500 gal. (better yet a 1000 gal) tank next to it.  LP will store a very long time.  Now you're all set for months long outage for under $3k.
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring with PVOutput.org
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,348 ✭✭✭✭✭
    I do not like the Edge system for many reasons. I helped a friend install one and I told him I won't say I told you so at the end. He now agrees about the drawbacks.

    There are grid inverters that will output some power during an outage in the hours the sun is out, like the SMA TL and up series.

    There are ways to make an outdoor propane tank safe (wildfires and earthquakes) without burying it. If you have the space install a propane tank large enough for a week or a month.

    One can buy a dual fuel  7 -9 Kw genset at costco for 700 dollars for a spare.

    Good Luck! You are smart to want to solve this problem!

    Our town almost burned to the ground 2 summers back. Once they shut power down there was no gasoline supply and all of those folks with gasoline gensets left during the summer heat. This went for 7 days. The people who leave can't get back in with the sheriff blocking all the roads. Piles of refrigerators at the dump from all the spoiled food. 
    "we go where power lines don't" Sierra Nevada mountain area
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • bill von novakbill von novak Solar Expert Posts: 891 ✭✭✭✭
    dcbour said:
     . . .wondered about something like Aims 24v 4kW pure sine inverter, a minimal set of batteries to run inverter to handle 6kW (for startup surge of ac, etc) at 24v, switch from input on inverter to output should power go out so can run over same wire across the house, a simple 120v charger to keep batteries running since can't have input on same line as output on inverter according to the Aims user guide.

    You are talking about AC coupling.  I don't think the AIMS supports that.  (Has to be a bidirectional inverter.)  You'd need something like a Radian if you want 240V.  And with the minimum battery size for the Radian you're looking at ~6K total cost.

    Your most reasonable option is a generator, as others have mentioned.

    Other options:

    1) Install a second small system that uses an SMA inverter with Secure Power.  That gives you some power during an outage.

    2) Switch to a StorEdge plus a battery.  You'll also need an autotransformer and lots of rewiring to support a subpanel.

    3) Convert your EV to allow it to power your house.  Instructions are available on-line; there are several ways to do it.
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