Enphase IQ7Plus-72-2-US with Enphase Combiner and Transfer switch

[bhoth]

Hi All,

I am brand to having a system installed and just learning as I go. My system was just installed yesterday with 22 REC360AA Black panels with Enphase IQ7Plus-72-2-US micro-inverters and an Enphase combiner.

In the event of a long term power outage, I want to be able to unhook the power coming out of the combiner and connect it to the transfer switch and have power from the panels off grid.

Has anyone attempted this? I gather this is not legal but again in the event of a long term power outage, I want to know if this is possible.

Thank you,

 

[FilterGuy]

That line of micro-inverter is designed as a grid-interactive inverter and will shut down if it does not see the grid power being on. Consequently, you can't get power from them when the grid goes down.

Some folks have been able to fake out grid-interactive inverters with an off-grid inverter pretending to be the grid.... but that discussion definitly takes us well into the danger zone.

 

[Herb]

So here is what I have done, please make sure you understand that this is not a guide or a recommendation, but it is a simple solution with all legal precautions. We had a 4 day outage not long ago. I have an Enphase IQ PV system. It will not work during a power outage we all know why, it is for safety of the repair crews. But, what I do, is I disconnect 4 of the panels from the micro inverters since they are dead right, and then use the panels as any other panel. I connect those 4 panels to my charge controller and my small 5kW DIY Power-wall, the panels charge the batteries and I can use the power (limited) during day and night for essential needs only, like coffee maker, fridge, PC, small electronics, fans, etc.... rinse and repeat the next day. I need to figure out how to cool the house some during hot summers in case of an extended outage, maybe some window units but they use quite a bit of power the house uses a 3ton AC and it would require 13kW of storage with soft start to get it going. In the winter the furnace works fine and keeps the house a lot warmer than space heaters or a gas log. Input is appreciated. I would stay away from using Inverters to feed the micro inverters just my 2 cents.

 

[Ampster]

I would stay away from using Inverters to feed the micro inverters just my 2 cents

I would add that a properly configured hybrid inverter can safely AC couple to a grid tie inverter. That process is a lot more commplicated than just feeding the microinverters.

 

[Herb]

That would be the proper choice, IMO, a nice hybrid inverter, safety first and always.

 

[newbostonconst]

As Ampster said there are many Hybrid inverters that can do this. They fake out the Enphase inverters to think they are connected to the grid and then when the inverters produce to much power (power has to go somewhere - if you are producing 5k and only using 1k something has to be done to the power) the hybrid inverter changes its frequency and the micro inverters see this as a fault and start shutting down power.

You will at the least need a hybrid inverter and a large battery. Guessing around $10k to do this and it really isn't DIY.

 

[Herb]

I have looked at their new Enphase battery backup solution but the cost is way up there for me, so I'm looking at other alternatives hopefully on the more economical side, power outages here are not a big problem so far but I like to be ready just in case, as long as I can have the basic needs covered on a daily basis we will OK, we do have grand kids and that is worrisome. My guesstimated budget for a hybrid inverter is around 5K, the house has a 3 ton AC unit so I have to take that in consideration. A 13kW battery backup system including inverter will most likely be double if not triple my budget!

 

[frosa04]

As Ampster said there are many Hybrid inverters that can do this. They fake out the Enphase inverters to think they are connected to the grid and then when the inverters produce to much power (power has to go somewhere - if you are producing 5k and only using 1k something has to be done to the power) the hybrid inverter changes its frequency and the micro inverters see this as a fault and start shutting down power.

You will at the least need a hybrid inverter and a large battery. Guessing around $10k to do this and it really isn't DIY.

Any recommendation for a hybrid inverter that works with the Enphase IQ7 for a 4.5kW AC coupling system?

 

[newbostonconst]

Solark (many sizes but all very similar)
Outback (GS4048 or GS8048 or Skybox)

Here is a list of others.

Hybrid Inverter | Hybrid Solar Inverter | altE

Hybrid inverters, mostly used in grid-tie solar systems, can provide backup power when the electric grid fails. Call 877-878-4060 to size your system today.

www.altestore.com

 

[Hedges]

Assuming those IQ7 do have "frequency-watts" function, varying power output when the line frequency varies, what you want is a battery inverter designed to control them by adjusting frequency. Some of those are hybrid (have both PV and battery inputs) and some are not.

Here's the original frequency-shift battery inverter (or rather latest model of the original series which implemented it)

SMA Sunny Island 6048-US Inverter

The SMA Sunny Island 6048-US inverter has a maximum efficiency of 96 percent and can be used in off-grid and grid-tie battery back-up systems. 6048-US

www.altestore.com

Not inexpensive, but some are available from liquidation sales, such as this pre-wired bundle of two for $5000. I use Sunny Island in a large AC coupled system for whole-house backup.

SMA Sunny Island 6048-US Inverter

The SMA Sunny Island 6048-US inverter has a maximum efficiency of 96 percent and can be used in off-grid and grid-tie battery back-up systems. 6048-US

www.altestore.com

A few forum members have Enphase microinverters AC coupled to a battery inverter (At least one Schneider, others Enphase Encharge)

A battery large enough to be useful is not cheap either. It is included in Encharge, but for most others you have to buy it separately. It is easily $2000 (DIY LiFePO4) to $5000 (AGM) or over $10,000 (commercially assembled lithium) for about 14 kWh of usable storage.

Larger systems would have enough surge power from battery (about 10kW) to start the motor in a central air conditioner, after which power from PV keeps it going.
A smaller system could power refrigerator, phone/internet, and the like. (Not sure there are any small, inexpensive AC coupled systems.)

For a more economical approach, what you could do is rewire PV panels from microinverters to an offgrid hybrid inverter. The PV wires shouldn't be unmated while operating. What I would do is wire in extension MC4 PV cables from the panels to a DC rated switch or breaker panel. They could be switched off, then swapped to offgrid system by unplugging and plugging in to other wires. With a typical disconnect switch, it has to be turned off before the box can be opened, which prevents you from accidentally unplugging while turned on. (Run cables to connectors inside the box.)

SquareD HU361RB 600V DC 30 Amp 3-Pole Disconnect Switch

SQUARE D HU361RB Non Fusible Safety Switch, 30 A, NEMA 3R Rainproof, single throw 3 wire, 3 pblades

www.altestore.com

Multi-Contact 8' MC4 Connector Extension #10 AWG 600V

Click here for Multi-Contact Multi-Contact 8' MC4 Connector Extension #10 AWG 600V from altE® - Making Renewable Do-able since 1999.

www.altestore.com

But considering retail price of the switch (they're cheaper used on eBay, but that's the lowest I've seen retail), you would probably spend less buying a few solar panels locally (no shipping) and adding them to a hybrid inverter.

 

[Ampster]

Solark (many sizes but all very similar)
Outback (GS4048 or GS8048 or Skybox)

I had an Outback Skybox AC coupled to a 3.8 kW Solaredge GT inverter and 4 IQ7+ inverters. I am in the process of moving the Skybox to another home.
That installation will have the Skybox AC coupled to approximately 18 IQ7+ inverters.

 

[Herb]

Hello everyone, since the last post I have added an AIO inverter and a 12kW LiPo4 battery bank, so now I can run a mini split in case of an emergency, I still use the older backup system for lighting and small appliances so is a great combination and for extended power outages performs really well.

 

[Ampster]

Hello everyone, since the last post I have added an AIO inverter and a 12kW LiPo4 battery bank, so now I can run a mini split in case of an emergency, I still use the older backup system for lighting and small appliances so is a great combination and for extended power outages performs really well.