In A Pickle, Need Options

[AGDorsum]

Located in Tri-valley east of San Francisco. In 2012 we self-installed an Enphase system comprised of 20 250w Canadian Solar panels, 20 M215 GT inverters (2012 vintage so no throttling, on/off only), and an Envoy. In 2018 we upgraded our Envoy to an Envoy-S (with combiner box)and added a 1.2Kw Enphase battery. Panels are configured in 2 strings, 5 on garage and 15 on house.

Production/consumption are as follows:
Annual - 6.6Mwh/11.3Mwh
High Month - 781.6Kwh/1200Kwh
Low Month - 288.1Kwh/802.3Kwh
Avg/Day - 18.1Kwh/31Kwh

Our major issue is PG&E. We buy our electricity from a co-op, flat rate at $0.11 per KWh for the past 3 years. PG&E delivers the power through their infrastructure, for a fee. In 2020 we paid $0.235 for tier 1 and $0.296 for tier 2 per KWh net delivered. Fast forward to today, $0.282 for tier 1 and $0.355 for tier 2.

My question to this forum is:
What additional equipment/configuration is needed to increase production thereby reducing transmission costs Without breaking the bank. An added benefit would be to keep solar alive during grid outage.


Additional considerations:
Cannot reduce consumption, divorce will cost more than any upgrade.
No Enphase upgrade (cable, inverters, panels, and Envoy). Not an upgrade but a replacement of everything except mounting rails. Considering partial upgrade to 5 panels.
No room for additional panels.


With my (very) limited knowledge I came up with the following options:

1. Replace 5 garage inverters/panels with IQ8 inverters and 390+ watt panels. Add Enphase Q-Relay-3P-INT (if I can find it in the U.S.) to disconnect grid. No reporting to Enphase. Trying to find out if grid forming IQ8 inverters will keep M215 inverters alive while grid down.
2. Add inverter (grid forming) to AC-Couple existing Enphase, replace garage panels with 390+ watt panels DC connected to inverter. Battery required to keep inverter alive, not enough production to charge/discharge daily.

I would appreciate alternatives, options, suggestions, food for thought.

Lots of creative, resourceful folks on this forum, let’s see what you have.



Thank you for reading if you made it this far.

 

[svetz]

...What additional equipment/configuration is needed to increase production ... No room for additional panels.

Given that you have no room for additional panels you are in a pickle. There are some things you can do that will have minor impacts, e.g., keep them clean, remove anything casting shade on them, use SAM to optimize the panel tilt.

Personally, I suspect looking for creative solutions to add more panels is the best bet (e.g., vertical on the south wall, a deck roof made of panels, possibly stealth options like a shed or gazebo (panels out of sight on its roof). I suppose you could replace them with bifacials, but for them to get more power/area they need elevation and a high albedo (easier to do with a ground mount system).

... An added benefit would be to keep solar alive during grid outage....

IQ8s on your panels (you might only need 1) and installing an Enphase compatible ATS should do it. I'm not familiar with the "Enphase Q-Relay-3P-INT" you mention, but "3P" probably means three-phase so it doesn't sound like what you'd want. I have Enphase's Enpower (aka IQ System Controller), it's an ATS and neutral forming transforming and works well. I'm not sure how the older Enphase AC batteries work in the system vs the new IQ Batteries, something to check into.

today, $0.282 for tier 1 and $0.355 for tier 2

Yikes! I'd say at a minimum make sure you have enough battery to get you through tier 2.

Is natural gas available? If so, it might be cheaper to run a compatible generator through tier 2 periods via the Enpower when you don't have enough battery.

If you've an EV, Will has a video using his to power an inverter (which could also be fed to the Enpower as if it were a generator) to get you through "bad" days.

Replace 5 garage inverters/panels with IQ8 inverters and 390+ watt panels.

Efficiency has improved a little since you bought your panels. But most likely 390W panels will be physically larger than 250W panels, so this might not work.

... find out if grid forming IQ8 inverters will keep M215 inverters alive while grid down.

It will, but you need an ATS that Enphase controls (e.g., Enpower) for the IQ8s to switch modes.

Add inverter (grid forming) to AC-Couple existing Enphase, replace garage panels with 390+ watt panels DC connected to inverter. Battery required to keep inverter alive, not enough production to charge/discharge daily.

@GXMnow does this, he has a detailed thread discussing everything he's done.

 

[AGDorsum]

@svetz Thank you for the response! After reading @GXMnow and @Ampster (and yours) threads, I have made a decision on the direction to take. A lot of holes but it’s an iterative process.

AC-couple current Enphase system with 6-8kW GT inverter.

Inverter wish list: grid assist, grid forming, flexibility when to charge/discharge battery, LF a plus, 240v SP.

DIY 48vdc battery. 230-302Ah depending on $ per KWh.

Move current garage panels (5) to area that experiences 3-4 hrs partial shade.

Install new 410w panels (6) on garage, use to charge battery thru inverter/CC.


My goals.

1) Minimal reduction in current production.

2) Keep entire house energized during grid outage.

3) Use frequency shift to shutdown Enphase system if production exceeds consumption (during outage).

4) Use battery to supplement solar, if needed. Run house after sunset.

5) Charge battery from solar even if Enphase system is off.


Will what I’m proposing accomplish my goals? Oversimplified but it’s a first pass.

 

[svetz]

Install new 410w panels (6) on garage, use to charge battery thru inverter/CC.

Don't forget the 410W panels are physically bigger than your existing panels, so if there's no additional space with what you have then exchanging them for 410W panels won't do you any good unless it happens to fit roof geometries better.

AC-couple ...[existing]... Enphase system with 6-8kW GT inverter.

Rather than just decide based off the forums, I'd say build up a few scenarios and post them so you hear about some of the gotchas you might not otherwise expect.

One such scenario should be to price to compare against the Enphase solution (one IQ8 replacement and an Enpower). The Enpower looks pricey, but often times its because there are missing gems that you might really want and not know about or understand.

For example the Enpower has an neutral forming autotransformer (also has grid sensors, relays, and a generator input that can autostart the generator when needed and run maintenance). One of the unexpected gripes people have with some inverters (e.g., Sol-Arc) is that 8k inverter is only 4k per leg (example video, their solution (a later video) was to add on an autotransformer at a loss of efficiency).

Other advantages of a "full" Enphase solution might be better than AC coupled is that for large power startup during the day the system can draw from both battery and panels simultaneously (not all solutions can). You also get one-stop monitoring and support (you don't become Malcolm in the middle of two companies).

But run the scenarios, look at the prices and what you really get so you can make an informed decision based on your needs.

2) Keep entire house energized during grid outage.
4) Use battery to supplement solar, if needed. Run house after sunset.

During the day the panels will have a good shot at this, but at night you'll need a battery or generator. Battery prices are falling and the technology is making leaps and bounds.

The IQ battery prices have come down, but I suspect they'll come down a lot more. I bought a 3 & 10 planning to hook my generator up later...but found out my generator won't work in concert (too dirty, needs to be an inverter generator).

But, you might be able to swap a single existing microinverter for IQ8 microinverter, add on an Enpower and generator and have what you need at a good price that allows you an upgrade path for when battery prices drop more.

5) Charge battery from solar even if Enphase system is off.

An AC coupled system setup to work with Enphase will either turn Enphase's panels on/off or throttle control them. The latter is preferable but with even a moderately sized battery either should work well enough. But, turning the panels back on takes 5 min, so you can't get "combined" power of panels and batteries with those solutions.

Hope that helps some!

 

[AGDorsum]

Don't forget the 410W panels are physically bigger than your existing panels, so if there's no additional space with what you have then exchanging them for 410W panels won't do you any good unless it happens to fit roof geometries better.

Replacement 5 panels are each 1.5 inches wider and 18 inches longer. My restriction on the garage is width so these will fit. 6th panel will be installed on a west facing rooftop.

Rather than just decide based off the forums, I'd say build up a few scenarios and post them so you hear about some of the gotchas you might not otherwise expect.

One such scenario should be to price to compare against the Enphase solution (one IQ8 replacement and an Enpower). The Enpower looks pricey, but often times its because there are missing gems that you might really want and not know about or understand.

I did run a couple of scenarios with just Enphase to see what the cost would be. First option was to replace existing system (not panels) with IQ series - damn expensive and toss investment in existing Enphase equipment.
Second option was similar to your suggestion, i called Enphase support to find out what was required. Basically IQ components not compatible with any of my existing components. Per support, I would need an IQ8 inverter ($189), IQ Combiner ($695), Encharge 3 ($2980)+Encharge 10 ($8935), IQ Cable ($17). Monitoring 2 systems would be required ?
Expectation for new system is 280Ah battery ($3000), Inverter ($3500-$4000), 6 replacement panels @ $125 ea ($750), misc (monitoring app, etc.) ($400).

Hope that helps some!

Absolutely, makes me think (getting more difficult every day). Thank you

 

[onokai]

How about a bigger battery to get thru a longer dark period

 

[AGDorsum]

How about a bigger battery to get thru a longer dark period

Hopefully a 14KWh battery will get us through the night. Wife has agreed to limit water/dryer use and to leave the water heater in heatpump mode.

 

[Hedges]

Canadian Solar 250W panels appear to be around 155W/m^2
Other panels are 200W/m^2 or a bit more.
So by replacing them you could boost output by a third, maybe more.

Canadian Solar CS6P-250PX (250W) Solar Panel

 

[Hedges]

Hopefully a 14KWh battery will get us through the night. Wife has agreed to limit water/dryer use and to leave the water heater in heatpump mode.

That's how much usable I have. Several old refrigerators are hogs, consume that much. Simply letting them coast until sunup would use much less.

Per support, I would need an IQ8 inverter ($189), IQ Combiner ($695), Encharge 3 ($2980)+Encharge 10 ($8935), IQ Cable ($17). Monitoring 2 systems would be required ?
Expectation for new system is 280Ah battery ($3000), Inverter ($3500-$4000), 6 replacement panels @ $125 ea ($750), misc (monitoring app, etc.) ($400).

Your system predates UL-1741-SA. I think also RSD.

I think you could substitute any older model inverter. For instance, Sunny Boy which can AC couple to Sunny Island (which isn't so cheap). Many newer UL-1741-SA inverters can AC couple with many battery inverters.

There are some hybrids which use batteries (optional for some models).

Battery is useful to keep critical loads running. It can't compete with utility, trying to avoid higher priced tiers or times of use, with big-name batteries. Maybe bargain brands and DIY. Batteries usually cost 10x to 20x what solar panels do, so more PV is the best way to combat utility costs. That with a small battery can power major house loads during the day if grid is down.

 

[svetz]

...Per support, I would need an IQ8 inverter ($189), IQ Combiner ($695), Encharge 3 ($2980)+Encharge 10 ($8935), IQ Cable ($17). Monitoring 2 systems would be required ?

Might try calling them again, sounds like they were somewhat confused.

Do you already have a whole house ATS?

Ask why they didn't quote an IQ System Controller (aka Enpower) and if you really need IQ Batteries (Encharge 3/10) for daylight power? That you can plug a generator into the IQ System Controller for nighttime use (so why spend the money for batteries when it's only for occasional emergency nighttime use and they can be added in two years when prices come down?).

Ask why they say you need 2 monitoring systems when you already upgraded to an Envoy-S. Ask why you need an IQ Combiner when you have empty breaker space in the Envoy's existing combiner box.

Ask why, if you do buy an Encharge 3, you need to buy an additional IQ8 or change any of the existing roof wiring (e.g., IQ cable, IQ Combiner).
(my roof is all IQ7s, the IQ8s are in the Encharge 3 and very capable of turning the roof microinverters on).

...Encharge 3 ($2980)... [whereas a new] 280Ah battery ($3000)

A single $2980 Encharge3 is 3.6 kWh. A $3000 12V 280 ah battery is (12x280=) 3.36 kWh and doesn't come with monitoring, tech support, or probably as good a warranty (also sounds way expensive, pretty sure you can do better). On the downside, the Encharge3 has a 1.28 kVA continuous inverter, so it'll power the fridge and lights, but probably nothing else. The flip side is buying a hybrid inverter big enough to power everything is pricey upfront and a single point of failure. Every Encharge 3/10 you add on later is another 1.28/3.84 kva of inverter and they can be added on as you can afford them.

... so these [410W panels] will fit.

Sounds like you'll want IQ8s for them, the old microinverters won't be able to handle them. So, with an Enpower you wouldn't need their IQ batteries for daylight power. You can probably run the panel output directly to the Envoy's IQ combiner box (bet you have an empty breaker slot). As you undoubtedly read above you can plug a generator into the Enpower...but theoretically you should be able to plug in an off-grid inverter ( haven't actually heard of anyone who's done it, probably because a generator makes more sense with battery prices the way they are).

Sorry if I sound so pro Enphase, it's just the system I have and know. Hopefully, when you put all the different scenarios together without fluff stuff the price is comparible. But I can't say that it will be. Anyway, hope this is of some help!

 

[AGDorsum]

Canadian Solar 250W panels appear to be around 155W/m^2
Other panels are 200W/m^2 or a bit more.
So by replacing them you could boost output by a third, maybe more.

my existing panels are CS250W connected to M215 MI. During best conditions I am generating between 206-214W per panel. M215 is only rated to 215W and will clip at 225W. After 9+ yrs they are performing quite well. I do clean them every spring but wife says I have to curtail my rooftop adventures now that I am a septuagenarian.

Your system predates UL-1741-SA. I think also RSD.

Correct. Micro inverters shutdown, no throttling.

 

[AGDorsum]

Might try calling them again, sounds like they were somewhat confused.

Do you already have a whole house ATS?

Good idea, first contact was when they recommended the relay instead of the MID. I did find the relay, it’s only sold in 50hz markets and supports 1-3 phase. Too bad, WAY cheaper than the switch if you only need to disconnect from grid.
I will see what support says about adding just the Encharge batter. Previously, both techs said IQ devices do not talk to Envoy-S, hence the need for IQ Envoy and switch.
No ATS.

A $3000 12V 280 ah battery is (12x280=) 3.36 kWh and doesn't come with monitoring, tech support, or probably as good a warranty (also sounds way expensive, pretty sure you can do better).

$3k was for 48V DIY (51.2*280=) 14.33 KWh. I was looking at Solar Assistant or the homegrown solution by @BarkingSpider for monitoring.

Sounds like you'll want IQ8s for them, the old microinverters won't be able to handle them. So, with an Enpower you wouldn't need their IQ batteries for daylight power.

The 410W panels will be DC connected to a charge controller and feed the battery.

 

[AGDorsum]

After multiple calls to Enphase support they have confirmed no backwards compatibility from IQ to previous versions. In effect you will either have two separate systems or completely replace existing.

Moving on, we have decided on the following:
1. Move 5 garage panels (Enphase M215) to less desirable location (partially shaded 2-4 hrs)
2. Install 5 410w (Znshine Solar ZXM6-NHLDD144-410/M) on garage, DC connect to SCC to charge battery.
3. DIY 14 KWh 48vdc battery.
4. AC-Coupled 6-8kw GT inverter

Starting threads for battery build and inverter selection.

 

[svetz]

After multiple calls to Enphase support they have confirmed no backwards compatibility from IQ to previous versions. In effect you will either have two separate systems or completely replace existing.

Sounds like they're giving you the "safe" answer rather than the best answer... from the support site:

Brian Messinger (Moderator)
Yes, you can mix IQ microinverters with non-IQ microinverters (like the M series). The only extra item you would have to do would be to purchase an IQ Envoy (North America only) so that the microinverters can communicate their production, receive updates, etc.

All 240V 60 Hz GT inverters have to synchronize to the grid, so you can match anything from any vendor and have it generate power. As Brian said, the problem is getting reporting on them and as the Envoy can communicate with both M & IQs, I don't see any issue. The off-shore tech support has never been great, sounds like it might be spreading. The self-training/certification on their website would probably serve you better.

But, you're right to go elsewhere if their support has become so bad they don't want to work with you. Look forward to your new threads and adventures.

 

[AGDorsum]

I wouldn’t go so far as to say Enphase support is bad or they didn’t want to work with me. More like their product line could not support my requirements at a reasonable (to me) cost. Basically they said M-series equipment talks to M-series inverters and Envoy/Envoy-S, IQ-series equipment only talks to other IQ compatible equipment (not compatible with M-series). The way I understood it was its no different from trying to combine two totally separate products, you can parallel them but not mix them (hope that makes sense).
The Envoy’s (M-series and IQ) only do reporting and use different protocol, do not control GTI’s. To have the system functional during an outage you have to incorporate an IQ-switch to disconnect grid and allow IQ-series GTI’s to operate. Not what I was expecting or wanting to hear.

 

[svetz]

I had to look a little deeper, sure enough, I was wrong and tech support did steer you right:

Can an IQ Envoy work with M-Series microinverters?​

No. An IQ Envoy can only communicate with IQ6/7 microinverters. IQ Envoy cannot communicate with M-Series microinverters. You must use an Envoy S metered to communicate with M-Series microinverters. Note that an Envoy S metered cannot communicate with IQ6/7 microinverters.

I was confused in that I thought the different Envoy models all did the same thing. Sorry about that!

 

[AGDorsum]

No worries, all’s well