enphase IQ7+ vs SolarEdge with optimizers

[Coach v]

I am planning a 6 kwh DIY grid-tie solar system for my home in Northern California. Most of the installers I have talked to prefer Enphase. The price is about the same between the two. I know I need to add the Enphase envoy for monitoring, but I assume monitoring comes with the SolarEdge HD Wave inverter? The SolarEdge StorEdge also seems interesting, especially with all the PG&E outages due to fire concerns that have been talked about (we do have a generator) .

What are your thoughts between the two products/technologies?

[jflorey2]

Do you have shading issues? If not a string inverter may be a cheaper/simpler solution.

The Enphase IQ8 line (just coming out now) also has a backup-power option, but I wouldn't choose them if you timescale is "soon."

Both work well. The Enphase system is a little simpler - one less piece of equipment.

[J.P.M.]

If you have no shade or slight shade, KISS and take Jeff's advice on a straight string inverter. Simpler, fewer parts to fail and if not less expense, probably no more.

If the application has enough shade to warrant micros/optimizers, I be careful about the economics of the project.

[ButchDeal]

I am planning a 6 kwh DIY grid-tie solar system for my home in Northern California. Most of the installers I have talked to prefer Enphase. The price is about the same between the two. I know I need to add the Enphase envoy for monitoring, but I assume monitoring comes with the SolarEdge HD Wave inverter? The SolarEdge StorEdge also seems interesting, especially with all the PG&E outages due to fire concerns that have been talked about (we do have a generator) .

What are your thoughts between the two products/technologies?

SolarEdge does include the monitoring for free. you just need to connect the inverter to ethernet.

on your price calculations did you include the cost of the proprietary buss cable for the enphase? it is not cheap.

Most of the installers are using these two products as the meet all the required rapid shutdown and safety requirements for California (and other states).

[Coach v]

SolarEdge does include the monitoring for free. you just need to connect the inverter to ethernet.

on your price calculations did you include the cost of the proprietary buss cable for the enphase? it is not cheap.

Most of the installers are using these two products as the meet all the required rapid shutdown and safety requirements for California (and other states).

Are these the buss cables you speak of? https://tandem-solar-systems.com/buy...e-q-12-20-200/

I am in the beginning phases of design and planning, but would like to get on it rather quickly. I understand the requirement for rapid shutdown, but not the details of it. Is this in addition to an AC disconnect? Is the rapid shutdown and safety requirements available on a straight string inverter?

[Coach v]

Do you have shading issues? If not a string inverter may be a cheaper/simpler solution.

The Enphase IQ8 line (just coming out now) also has a backup-power option, but I wouldn't choose them if you timescale is "soon."

Both work well. The Enphase system is a little simpler - one less piece of equipment.

It will be a ground mount system facing 180-200 degrees with little to no shading. What string inverter would you recommend I look into?

[ButchDeal]

Are these the buss cables you speak of? https://tandem-solar-systems.com/buy...e-q-12-20-200/

I am in the beginning phases of design and planning, but would like to get on it rather quickly. I understand the requirement for rapid shutdown, but not the details of it. Is this in addition to an AC disconnect? Is the rapid shutdown and safety requirements available on a straight string inverter?

yes that is the 72 cell version and you would need one section per optimizer.
If you are doing a ground mount then you do not need rapid shutdown. to meet the current rooftop requirements you pretty much need optimizers or micros.

for a ground mount I would suggest solaredge or SMA

[JSchnee21]

For ground mount, if using a string inverter (or Solar Edge) you will likely need to enclose the array with fencing due to the high DC voltage (350-600V DC). With Enphase, since each panel only puts our 120V AC, your AHJ may allow you to skip the fence. How far is the array from your house? How large will it be (DC kW?) -- I think you mentioned 6kW DC given that you're looking at a ~7600kW inverter.

Have you through about how you will run the current from the array back to your PoCo service feed? Are you trenching? HV DC requires much less current (string & SE), and thus, less copper than 120V AC (Enphase) for example. I'm assuming this is grid-tied since you mentioned PG&E.

There's nothing magical about the StorEdge. There are lots of AC coupled battery solutions these days. The biggest problem with most battery systems is that they cannot put out enough continuous current to run your AC. So you'll need to re-wire your home's load center to split the loads between that which is on battery backup and that which is not.

[Coach v]

For ground mount, if using a string inverter (or Solar Edge) you will likely need to enclose the array with fencing due to the high DC voltage (350-600V DC). With Enphase, since each panel only puts our 120V AC, your AHJ may allow you to skip the fence. How far is the array from your house? How large will it be (DC kW?) -- I think you mentioned 6kW DC given that you're looking at a ~7600kW inverter.

Have you through about how you will run the current from the array back to your PoCo service feed? Are you trenching? HV DC requires much less current (string & SE), and thus, less copper than 120V AC (Enphase) for example. I'm assuming this is grid-tied since you mentioned PG&E.

There's nothing magical about the StorEdge. There are lots of AC coupled battery solutions these days. The biggest problem with most battery systems is that they cannot put out enough continuous current to run your AC. So you'll need to re-wire your home's load center to split the loads between that which is on battery backup and that which is not.

Thank you for your thoughts!

You make a good point about fencing, but I have seen a few dozen ground mount residential systems in my county without fences. I am unsure what they are running as far as inverters (AC vs DC). All the commercial solar systems do have fencing though.

I will be running an overhead wire from the ground mount solar, into my shop and over to that sub panel inside the shop, then to the main panel and down to the meter.

We do not have Air Conditioning in our house. We live at 3500' elevation and have never felt the need. We already have a a generator panel with our most needed circuits (fridge and freezers, power vent water heater, router, smoke detectors, reef aquarium, plus a few others) and a backup generator. PG&E is facing massive lawsuits from wildfires and is planning on large blackouts during Red Flag Fire Warnings. I am leaning toward not going battery backup, but thought I would look into it, especially with SGIP.

[JSchnee21]

Approximately what distance will your overhead run(s) be? Inverters have issues if your line voltage is too high, and there is too much resistance to current flow from the inverter back to the street. This can create a localized increase in line voltage of 10-15 or more volts (e.g. 245V + 15V = 260V) which can cause the inverter to shutdown if the conditions are right (full sun, high production, limited self consumption, increased resistance to current flow, and elevated line voltage)

This is usually more of a problem with larger inverters that put out 30 or 40 amps @ 240V.

If you already have a decent generator, especially a large static one with NG, Propane, or Diesel, and an ATS. There's no need for a battery solution unless you want to load shift for a TOU plan.

[Coach v]

Approximately what distance will your overhead run(s) be? Inverters have issues if your line voltage is too high, and there is too much resistance to current flow from the inverter back to the street. This can create a localized increase in line voltage of 10-15 or more volts (e.g. 245V + 15V = 260V) which can cause the inverter to shutdown if the conditions are right (full sun, high production, limited self consumption, increased resistance to current flow, and elevated line voltage)

This is usually more of a problem with larger inverters that put out 30 or 40 amps @ 240V.

If you already have a decent generator, especially a large static one with NG, Propane, or Diesel, and an ATS. There's no need for a battery solution unless you want to load shift for a TOU plan.

The ground mount array will be about 20-30' from the back of the shop. Then the wire will run the 30' of the shop to the sub-panel. The shop sub-panel to the main panel is approx 15'. The main panel to the meter is about 500'.

Our genset is just a decent construction generator that we use while building the house. We do have the wiring hooked up to go from the generator panel through the wall to the small generator pad (we just put the generator out there when we need it). We have ran it 5 times in the 11 years at the house, but think we will use it more this year with POCO plans on shutting down power in fire warning weather.

[bcroe]

You might check your line voltage and see it it runs pretty during the solar day. That
condition tends to cause inverter trip out when your array is pushing it even higher. If
all your long runs are made with high voltage DC, and inverters are close to your PoCo
input, you would buy a bit of margin besides decreasing system losses. Bruce Roe

[Mike90250]

> With Enphase, since each panel only puts our 120V AC .....

Odd, I thought they ran 240V ?

[Coach v]

You might check your line voltage and see it it runs pretty during the solar day. That
condition tends to cause inverter trip out when your array is pushing it even higher. If
all your long runs are made with high voltage DC, and inverters are close to your PoCo
input, you would buy a bit of margin besides decreasing system losses. Bruce Roe

You lose me with your first sentence?

Would increasing or having the proper gauge wire help with line voltage/resistance?

My longest run is by far the main panel to the meter. I built the house and I know we used the proper guage wire for that run and my electrician friend said my feed was clean? I figure the run from the solar panels to the sub panel they will be feeding is around 60'.

[bcroe]

If your line voltage is around 220VAC you should have no problem. If it is already 240+
you might have a problem when solar pushes it even higher. Your smallest wire size is
determined by the current that must be carried and the circuit breaker. But sometimes
over sized wire is advantageous to reduce the voltage shift. The other way is arrange
things to keep wire as short as possible, such as having the (AC voltage sensitive) solar
inverter as close to the AC breaker as practical (by making as much of the run with the
DC wiring as practical). Bruce Roe