Need advice on Solar Expansion and Battery Backup (Currently Enphase IQ7 solar system)

[VictorBurgos]

Hi all, I hope you’re all doing well. I rushed into solar in 2021 without doing enough homework soon after I moved into my new home in Northwest Florida. The solar guy was convinced that it would bring down my electric bill and even give me back some at the end of the year (net metering).

The issue is, it never has They didn’t give me enough panels, which I thought they didn’t, we didn’t have enough electric bills in the house and they made a guess, I felt it was wrong and pressured them to give me a few more panels, but even then, it wasn’t enough to offset usage. Let’s not even get into the pricing.

It’s been two years, and I’ve since then I’ve remodeled the home a bit, and I did my best to be as energy efficient as possible, but I also work from home as a game developer (so I’m definitely sucking up a lot of energy from the PC usage)

Current solar system:​

• One IQ Gateway (IQ Combiner 3)
• 46 IQ7 Microinverters
• Hyundai Panels (not sure model)
• 3 Arrays. 28, 5, 13
• PV Size looks to be 14.49
• Solar production on the Enphase app says it’s produced 15.77 MWh over the past year.

PV Shutoff
There’s another PV panel, not sure what that is, but it says Warning “Dual Power Supply” Grid and PV Solar Electric System. Seems to be connected to the shutoff.

Electric Situation:​

Net Metering
Standard Residential Rate (RS-1) (not on Time Of Use, because we currently don’t qualify because of summer highs, but once HVAC is not much in use, we’ll try to get that, we don’t know the exact rates for TOU since they didn’t want to disclose that with us unless we qualified)

Current Rates:

• Non-fuel energy charge: $0.09564/kWh up to 1000 kWh, $0.10563 above 1000.
• Fuel charge: $0.02670/kWh up to 1000 kWh, $0.03670/kWh above 1000.

Feb-May and Oct seem to be very low usage (only the base charge + taxes + fees, so ~$26), but every other month blows because of the heating/cooling.

According to FPL bills:

• Over the past year, we have used: 17920 kWh
• Over the past year, we have produced: 9417 kWh

Home Details:​

• Size: 3100 sqft
• HVAC: Goodman AVPTC426014 w/ heat pump using a Google Thermostat 4200 (12.4-17.5 kW)
• Lights: All LEDs
• Water Heater: AOSmith 50-Gallon Electric (used to have a hybrid, but it broke) with recirculation pump
• Pool Pump: Pentair IntelliFlo VSF
• Home Appliances:
  • Samsung Smart Flex Washer and Dryer
  • Samsung Dishwasher
  • Samsung Microwave
  • Samsung Family Hub Smart Fridge
  • Samsung Stove (which because of this, now I know is on recall!)
  • Multiple Alexas and Alexa Light Switches
  • 4 Air purifiers
  • 2 Dehumidifiers

I may be missing some things, but I think that takes care of the big items.

Goals:​

1. At minimum start seeing “$0 electric bills year-round”, now with that ~$25 minimum charge, I guess I’d need to see a check at the end of the year to offset that.
2. Have a battery backup in case of short-term outages, preferably auto-switch.
3. Have a long-term solution when the grid is down (in case of a hurricane), where solar and batteries can do their thing for a few days.
4. Offset the cost of the current solar payments.
5. See a ROI at minimum 2 years, maximum of 5 years, but flexible.
6. Maybe allow for a propane tank generator connection, to help solar/batteries.

Requirements:​

• DIY-friendly solution (duh!) with electrician check-up and final connections probably. But if adding panels is suggested, and if roof-installed, probably get someone else to do it.
• Batteries will most likely have to go in my garage, I have space on the inside wall that the main breaker and other solar connections are on, although my in-home breaker is actually on the opposite wall.
• Low maintenance.
• A good app to customize things if needed/check on things.
• Scalable preferred. If I need to add a battery, I’d like to.

What I’ve Done:​

I have done a bit of research already through YouTube, Reddit, and other forums. But it’s a bit hard to wrap my head around what my actual needs are and how to get that ROI.

I know there are Enphase batteries (3T/10T and 5P), and even did a quick work up with Enphase Installer App

Misc:​

In a power outage, especially long-term, I would stop non-essentials, like the pool pump and dryer. I could also go without the stove/oven, I have a propane wok burner and charcoal grill. I thought about maybe having another breaker for just “emergency items” like the fridge and HVAC.

Questions:​

• What options are available to achieve my goals? (it doesn’t need to be all of them)
• What kind of setups would you recommend for the actual design of the layout of things?
• How much battery storage do I need exactly?

Thanks for your time!

 

[DIYrich]

Enphase says it produced 15,770 kWh over the year
FPL says you consumed 17,920 kWh (I'm assuming over the same period as Enphase).
FPL says you produce (net) 9,417 kWh.

17,920 + 15,770 - 9,417 =24,273 total consumption, of which 15,770 was produced by Enphase, leaving a net purchase of 8,503.

So, you need about a 50% larger system. About 8kW, assuming same orientation (facing same direction, same tilt, etc.)

Suggestion:
On average, you are consuming 43kWh per day. Wild guess: 60kWh on a peak day.
If you want 1 day of battery, that is 60kWh, or about $12,000 worth of battery. Cheaper to add an 7kW generator for extended outtages (recommend combining the generator with a chargeverter). Propane powered generator with a 100# tank (about 5kWh per pound of propane, 5 days?)? Natural gas is better if reliable during hurricane.

Pick your favorite All-In-One. At the above level consumption, you may need:

• 2 EG4 18k
• 2 Sol-Ark 15k
• EG4 Gridboss with 2 Flexboss16
• 3 Growatt SPH 10000-TL-HU-US
• 2 Midnite Solar Rosie or The One

Did I miss any?
Add the new 8kW as DC PV into the AIO
Wire the Enphase into the AIO as AC PV

 

[Quattrohead]

First thing you should do is get yourself an Emporia energy monitor system to find out who the energy hog is. You think you know that it's your AC system and indeed it is but, how about that hot water researculation pump system ?
Also with your existing solar system, make sure they are not going to start getting grumpy with you if they are not seeing energy return. Check the verbiage of your contract for that.
I personally I'm running a whole home off grid in Central Florida with seven wall mount power pro batteries and two 18K inverters, currently have around 13 KW of panels and it is generally enough except for extended cloudy days, so I'm adding another 6 to 7 kilowatts soon.
The upcoming grid boss would be ideal for your situation, it can parallel up to three inverters, has grid connection, generator connection and shut offs along with four smart ports that can be used as inputs or outputs and controlled based on conditions, perfect for load shedding and AC coupling.

 

[VictorBurgos]

First thing you should do is get yourself an Emporia energy monitor system to find out who the energy hog is. You think you know that it's your AC system and indeed it is but, how about that hot water researculation pump system ?
Also with your existing solar system, make sure they are not going to start getting grumpy with you if they are not seeing energy return. Check the verbiage of your contract for that.
I personally I'm running a whole home off grid in Central Florida with seven wall mount power pro batteries and two 18K inverters, currently have around 13 KW of panels and it is generally enough except for extended cloudy days, so I'm adding another 6 to 7 kilowatts soon.
The upcoming grid boss would be ideal for your situation, it can parallel up to three inverters, has grid connection, generator connection and shut offs along with four smart ports that can be used as inputs or outputs and controlled based on conditions, perfect for load shedding and AC coupling.

Yeah, I was hoping they would have gone on sale for Prime Day, but since they aren't, I'll just be grabbing the 16-kit today and figuring things out. The HVAC is definitely the biggest culprit though, I had used it way more this summer than last.

And yes, the new water heater and that pump is definitely going to be on my list to analyze, it's a small pump though. https://www.amazon.com/Grundfos-GRU-595916-595916/dp/B000JG81AQ/ref=asc_df_B000JG81AQ. 25W. But I actually just went to look at it, and I should have looked after the new water heater was installed, but it looks like they set it to always on. I have it set to timer again with only a few hours a day when we're likely to take showers.

Do you have a link to the "grid boss" ? It sounds like it's what I am looking for. Basically something to use with my existing system, then add new system (maybe IQ8 array with Aptos 370W panels?), along with battery backup, and then have them all tied into the house.

Thanks for the reply btw.

 

[VictorBurgos]

Enphase says it produced 15,770 kWh over the year
FPL says you consumed 17,920 kWh (I'm assuming over the same period as Enphase).
FPL says you produce (net) 9,417 kWh.

17,920 + 15,770 - 9,417 =24,273 total consumption, of which 15,770 was produced by Enphase, leaving a net purchase of 8,503.

So, you need about a 50% larger system. About 8kW, assuming same orientation (facing same direction, same tilt, etc.)

Suggestion:
On average, you are consuming 43kWh per day. Wild guess: 60kWh on a peak day.
If you want 1 day of battery, that is 60kWh, or about $12,000 worth of battery. Cheaper to add an 7kW generator for extended outtages (recommend combining the generator with a chargeverter). Propane powered generator with a 100# tank (about 5kWh per pound of propane, 5 days?)? Natural gas is better if reliable during hurricane.

Pick your favorite All-In-One. At the above level consumption, you may need:

• 2 EG4 18k
• 2 Sol-Ark 15k
• EG4 Gridboss with 2 Flexboss16
• 3 Growatt SPH 10000-TL-HU-US
• 2 Midnite Solar Rosie or The One

Did I miss any?
Add the new 8kW as DC PV into the AIO
Wire the Enphase into the AIO as AC PV

Oh, this must be the grid boss

But yeah, I think this year was an outlier. I did more math, and the first year of solar was an overage of 5044 kWh. Last year it was 3896 kWh (I used the HVAC less, had the Hybrid Water Heater still, but used a small Midea Window AC for my office, which is the hottest part of the house). This year was the high 8503, with the new all-electric water heater (and looks like the pump was put on always on), and barely any use out of the window unit because I was doing pre-cooling with the HVAC (and in hindsight, since only one room needed the constant cooling, that was a grand mistake)

I don't have natural gas here. I don't even have propane, have to source the tank and propane. It's just electric here.

So, with this Gridboss, I should just be able to tie in both the existing IQ7 46 panel system, with the new array? I'm thinking IQ8 with Aptos 370W, but I'm open to other suggestions. I do have room for ground mounting probably an additional 5 panels as well (maybe more if I clear some bushes/trees)

Thanks for the reply!

 

[DIYrich]

So, with this Gridboss, I should just be able to tie in both the existing IQ7 46 panel system, with the new array? I'm thinking IQ8 with Aptos 370W, but I'm open to other suggestions. I do have room for ground mounting probably an additional 5 panels as well (maybe more if I clear some bushes/trees)

If you add IQ8 to IQ7, it doesn't help with "Have a battery backup in case of short-term outages, preferably auto-switch." You need an inverter to convert battery power to AC.

You need enough inverter to supply power needs when the sun is not shining. Guessing that you need more than 12kW, so 2 Flexboss 21.
If you are going to add an inverter (flexboss 21), you might as well add the new panels to the inverter, and not IQ8.

 

[AntronX]

What options are available to achieve my goals?

Turn up your AC thermostat.

 

[Quattrohead]

There is no official documentation or sales info for the Grid Boss yet, but search on here and you'll get a few ideas.
If you are adding more panels the first question is permit or not? Then shading or none. Then full monitoring or just basic fireman safety on off.
Your least expensive option is the latter, use Tigo TS4-A-2F safety devices and the built-in signaling on the EG4 inverter and that is all you need.

 

[VictorBurgos]

If you add IQ8 to IQ7, it doesn't help with "Have a battery backup in case of short-term outages, preferably auto-switch." You need an inverter to convert battery power to AC.

You need enough inverter to supply power needs when the sun is not shining. Guessing that you need more than 12kW, so 2 Flexboss 21.
If you are going to add an inverter (flexboss 21), you might as well add the new panels to the inverter, and not IQ8.

So you're saying that it'd be better to just find and Enphase IQ7 panel inverters with the expansion instead of trying to upgrade them to IQ8 with the new arrays?

When I was doing research I notice that while it's not possible to use IQ7 and IQ8 on the same system, it'd be possible to run 2 separate systems. Would it be possible to tie those 2 separate systems into an appropriate inverter for PV source/battery charging? Source

But, someone did suggest to just swap out all the IQ7s to IQ8s. Or just run the 2nd system with only battery back to critical loads, which is appealing. I just feel like if the grid went down, then all the IQ7 system (the largest bunch) would be wasted since they won't be doing anything.

It seems like the only way to get the sunlight backup is with IQ8 though. While I don't mind not having sunlight backup as long as the batteries can keep up with the demand for an outage I suppose.

Overall what is everyone's opinion on sunlight backup + battery? Is it worth it, stretch out the batteries/power over time?

I don't want my way overpriced panels to be sitting doing nothing when the grid goes down.

 

[VictorBurgos]

Turn up your AC thermostat.

Done

 

[VictorBurgos]

There is no official documentation or sales info for the Grid Boss yet, but search on here and you'll get a few ideas.
If you are adding more panels the first question is permit or not? Then shading or none. Then full monitoring or just basic fireman safety on off.
Your least expensive option is the latter, use Tigo TS4-A-2F safety devices and the built-in signaling on the EG4 inverter and that is all you need.

Yeah, I was able to find an article on it. It does look nice.

Because of the possibility of selling the house in the future, I'd probably go the permit route. I already did my own permits when renovating the inside of my house (turned open dining room into closed off office, new half-bath, remodeled other baths and kitchen and new flooring, so I am not adverse to DIY work!)

There is a bit of roof space left, and no shading. And I do have ground area as well without shading, and a few other areas I'd have to cut some trees down to make unshaded throughout the day.

I don't go on my enphase app as much as I used to, but I don't mind simple monitoring to ensure input/output is working as intended, but most inverters have something like that from what I see. But IIRC, if the grid is down and no internet, I wouldn't have access to that enphase app anyway, probably same with most other apps. If there are apps that can be Bluetooth or ethernet mounted, that'd be the way.

The question is, how to ensure that I can use the existing IQ7 system and possibly/probably tie stuff into the IQ8 (or use something else entirely I guess, I'm adverse to that either, I'm just more familiar with my own system)

 

[Quattrohead]

Your Enphase IQ7 system can be AC coupled to the EG4 18K and will continue to run because the inverter will become it's "grid"
If you love the IQ 7 system they are very easy to find used if you don't want to buy new but conversely the Tigo safety modules are inexpensive and the signaling is already built into the inverter.

 

[DIYrich]

So you're saying that it'd be better to just find and Enphase IQ7 panel inverters with the expansion instead of trying to upgrade them to IQ8 with the new arrays?

No.
If you want battery backup power, you need an inverter to convert the battery power to AC power you can use.
Most inverters that provide backup power also have String MPPT to convert the PV power to battery power.
Why buy IQ8's (or even IQ7's) for the new panels when you have a perfectly good String MPPT that could be used.

 

[Arob]

I added 2 Enphase 5P batteries and a Controller 3 to my system a year ago. This is a system with IQ7X inverters and a Combiner 3. In order for the 5P's to be used with the Combiner 3, we added the comms kit. This adds the wired communications capability that the 5P has. The 5P requires this and no longer uses the Zigbee protocol the 3T/10T use. Apparently the wireless comm was/is problematic.

The controller 3 is not required but adds functionality I wanted. I recently added an array to the system and was able to set a grid export limit so I don't run afoul of the local utility.

The cost of the 5P has dropped over $1k since I bought them last year. I may add a third, jury is out right not on need. As for the DIY aspect of this I have engaged an installer that knows his stuff. I'm lazy and for gods sakes don't want to haul panels up a ladder so using a pro is money well spent.

When we added the 5P's and controller we also installed a Span Smart Panel. That has been great for knowing exactly what circuits are using up the power.

There are much cheaper solutions, you can use 3rd party batteries with Enphase but I think for functionality the 5P is worth a little more if you already own Enphase.

 

[GXMnow]

I have a smaller Enphase system with just 16 iQ7 inverters. My usage is also far less than yours. No pool and natural gas for the big heating items. I know we get very good sun in in Southern California, but your production numbers still seem a bit low. Do you get shade on your panels? My 16 iQ7's with 300 watt panels produced 8,000 KWHs each year. Divide the production of 8,000 / system panel kilo watts 4.8 = 1,666 sun hours for the year. In your system, even dropping to 250 watt panels x 46 = 11,500 watts of panels 11.5 KW. 15,770 KWHs / 11.5 KW = 1,371 sun hours on the panels. And if the panels are any bigger, the numbers look even worse. Do you get a lot of clouds, that would do it as well.

I have a crazy long thread about my journey to add battery storage to my Enphase system. As good as my results are, it is tough to recommend due to the challenges of controlling my Schneider XW-Pro inverter. The newer "All in One" systems like the EG4 18K-PV look like a much smoother path.

When I did my system, there was no All in One that could do it, and Enphase did not have off grid capable batteries so no backup power. Things have changed a lot in 4 years.

Enphase is certainly going to cost more, but going with a system controller and the 5P batteries will be the best integrated system. They also have an EV charging unit if you go there. If cost was not a big concern, that is the smoothest route. With your consumption numbers, I would think you need about 4 of the 5P batteries.

If you go with an All in One like the 18K-PV you need to make sure it is enough power to manage the AC coupled solar. The battery inverter power must be more than the solar inverter power capability. If yours are the same base iQ7 as mine, that is 240 watts per inverter. Other models are more powerful. 46 x 240 watts = 11,040 watts of grid tied inverters. That is right at the limit of one 18K-PV as the battery to AC inverter is 12,000 watts. Will you backup everything in the house during a grid failure? I would recommend a separate backup loads panel and only backup things you need after the hurricane. That will greatly extend how long you can run on the batteries. During my last outage, I don't have my clothes washer dryer on the backup panel, but it was no big deal to run an extension cord over and do a load. My system backs up the refrigerator, computer gear, basic lighting, the furnace and gas stove igniter, cell phone chargers, and the main TV and Dish Net box to be able to watch news etc. I don't even think about backing up my central A/C. The Schneider inverter I have will run it, but it will suck the batteries down way too fast. I have 36 KWHs of battery capacity. If you do want to just backup everything, I would say you need 2 of the 18K-PV inverters. Each one can supply 50 amps at 240 volts. My Schneider XW-Pro is smaller at 6,800 watts or just 28 amps at 240 volts. But it can handle huge surge power without an issue where most of the All in One systems are a bit more limited for surge loads.

"Time of Use" is a whole different story. You should be able to go on the FPL web site and find the rates, it should not be a mystery. In most cases, "Time of Use" works against you with grid tied solar. The time you produce power, the power rate is cheaper, and when you need power in the early evening, they jack the rate way up. I wish I was back on the 2 tier billing, but all PV solar customers here were forced to ToU with solar. So even though my solar panels made 70% of my power in the first year, my total bills only dropped 30% as the power I still needed to buy at night was being charged at over double what I was paying before I went solar on the old tiered power plan. That was my main reason for adding the batteries. I store up my extra power and run on batteries all night. I cut my remaining bill to less than half. Then I added another 2,000 watts of panels with a DC charge controller to directly charge the batteries, and now I have zeroed my electric bill for nearly 2 years. But as I said earlier, my consumption is far less than yours. I only used about 11,000 kilowatt hours for the whole year. 8,000 from the Enphase panels and the other 3,000 from the DC coupled panels. I net exported a tiny bit to the utility and got a $30 credit at the end of the year. During the year, if I export and then import, it is 1 to 1 pricing at any given time block. Currently, my cheapest rate is 25 cents when the sun is up, 29 cents overnight, and 41 cents in the evening peak time, 4 pm to 9 pm. But the year end net export was bought off at just 2.5 cents to give me the credit. Last year they paid me 6 cents, and I was looking forward to that. Getting less than half was a slap in the face. I used to do a bit of extra battery charging overnight as it was easy, but now I am trying to make sure I do it at 8 am to 4 pm to save that extra 4 cents per KWH when I need to do it. Currently I have to do that manually as I don't have it programmed into my system yet.

And that is my issue with the Schneider XW-Pro that I am using....
The internal programming sucks. It is a great backup power system and the inverter hardware is rock solid, but the logic in the programming is just plain dumb. Though, they did finally fix one issue. If the battery does run down to the low battery cut off, it used to just sit and wait, now it will finally start a charge cycle on it's own. I ended up programming a PLC (programmable logic controller) to tell my XW when to charge and at how much power, and when to discharge and again, at how much power into my system. It does work well, but it was a major pain to setup. The new AiO units have a lot of this functionality built in now. But I don't know how well they let you program it around the different ToU billing rates. My brother has a Sun Power system using Enphase micros as well, and he is now looking into adding batteries as well. We are looking into the EG4 8K or 12K unit for him. His system is even smaller than mine. Any extra panels for him would then DC couple into the AiO MPPT solar inputs. He will use a decent amount of battery though. He has an EV and he wants to be able to store up daylight power to charge his car at night when he is home from work.