sandhillfarm
New Member
I have a property with multiple buildings and some interesting constraints and wanted to get some input on potential approaches for a system. I have attached an image of the property with buildings labelled.
A - main residence
B - garage / shop
C - barn
Goals of the system
1. Need AC passthrough to guarantee available power in winter months with lower light - at least until the system is fully expanded. Location is Northern Ohio. Not intending to do net metering due to the ultimate goal of using very little from the grid anyway.
2. Want to reduce electric bills as much as possible and ultimately with enough battery storage and/or panels approach zero reliance on grid energy. Ideally the system would be fairly easily expandable.
3. Want to (eventually) have 3-5 days battery backup power for critical loads. Large storms are becoming more prevalent in this part of the country and we have had multiple multi-day outages in the past few years. I know battery sizing here is strictly based on my needs. I am assuming initially 4-5
4. I am mostly interested in an EG4 system for ease of setup, positive reviews and the loads of documented installs and configurations that can be referenced.
Problems / Constraints
1. Buildings A & B have their own 200A service. I think this would need to be consolidated to have a single system.
2. If I went to 400A service I think this would be problematic for running a single GRIDBOSS. Some info in this thread: https://diysolarforum.com/threads/400-amp-service-and-eg4-grid-boss.97361/
3. Batteries will need to be located in building B (or potentially C), but not in the main residence (A).
4. The main residence has the highest load utilization. Monthly peak demand for the last month was measured at 12kW per my Emporia Vue 3 monitor. The residence still has some baseboard heat that I am hoping to eliminate / replace with heat pump units this year which should significantly reduce demand in winter months.
5. I plan on adding an EV charger at the garage but so far peak utilization is only 2kW there. It may increase in the summer with AC running - cooled by 36k BTU heap pump.
6. Buildings A & B both have critical loads in them.
My initial thoughts
I think I should consolidate to a single 200A service at building B and build the majority of the system from here using a gridboss and initially a single flexboss unit expanding to 2-3 in the future. The gridboss would feed the main panel of building B and I would feed building A as a 150A subpanel. I believe I can mount ~18kW of panels on the roof of building B. I would eventually like to do another ~12kW on building C. Potentially even adding a ground mount array if needed down the line. The biggest drawbacks to this that I see are: main residence service is reduced from 200A to 150A but this should still be plenty. Also having to run from B to A to feed the sub panel will probably be pretty expensive in terms of the necessary wire as it is right around 100 feet.
Questions
- Are there reasonable alternatives to the 200A/400A service issue? Is the gridboss my limitation here and is there a way to provide 200A everywhere with some other combination of inverters? Should I build 2 systems (this seems like a bad idea). I feel like I can only see the solution above that makes sense to me and I am blind to alternatives that might work as well or better.
- Am I building a way overkill system if I do not intend for net metering? Should I be looking to go smaller on the PV side and just throw a ton of batteries at this? I feel like I still need the combined inverters regardless to be able to potentially supply up to 200A.
My budget for the initial system is around $60k. This would including permitting, mounting brackets, conduit, ancillary hardware and a lot of DIY work but also paying a master electrician for final review and hookup, etc.
A - main residence
B - garage / shop
C - barn
Goals of the system
1. Need AC passthrough to guarantee available power in winter months with lower light - at least until the system is fully expanded. Location is Northern Ohio. Not intending to do net metering due to the ultimate goal of using very little from the grid anyway.
2. Want to reduce electric bills as much as possible and ultimately with enough battery storage and/or panels approach zero reliance on grid energy. Ideally the system would be fairly easily expandable.
3. Want to (eventually) have 3-5 days battery backup power for critical loads. Large storms are becoming more prevalent in this part of the country and we have had multiple multi-day outages in the past few years. I know battery sizing here is strictly based on my needs. I am assuming initially 4-5
4. I am mostly interested in an EG4 system for ease of setup, positive reviews and the loads of documented installs and configurations that can be referenced.
Problems / Constraints
1. Buildings A & B have their own 200A service. I think this would need to be consolidated to have a single system.
2. If I went to 400A service I think this would be problematic for running a single GRIDBOSS. Some info in this thread: https://diysolarforum.com/threads/400-amp-service-and-eg4-grid-boss.97361/
3. Batteries will need to be located in building B (or potentially C), but not in the main residence (A).
4. The main residence has the highest load utilization. Monthly peak demand for the last month was measured at 12kW per my Emporia Vue 3 monitor. The residence still has some baseboard heat that I am hoping to eliminate / replace with heat pump units this year which should significantly reduce demand in winter months.
5. I plan on adding an EV charger at the garage but so far peak utilization is only 2kW there. It may increase in the summer with AC running - cooled by 36k BTU heap pump.
6. Buildings A & B both have critical loads in them.
My initial thoughts
I think I should consolidate to a single 200A service at building B and build the majority of the system from here using a gridboss and initially a single flexboss unit expanding to 2-3 in the future. The gridboss would feed the main panel of building B and I would feed building A as a 150A subpanel. I believe I can mount ~18kW of panels on the roof of building B. I would eventually like to do another ~12kW on building C. Potentially even adding a ground mount array if needed down the line. The biggest drawbacks to this that I see are: main residence service is reduced from 200A to 150A but this should still be plenty. Also having to run from B to A to feed the sub panel will probably be pretty expensive in terms of the necessary wire as it is right around 100 feet.
Questions
- Are there reasonable alternatives to the 200A/400A service issue? Is the gridboss my limitation here and is there a way to provide 200A everywhere with some other combination of inverters? Should I build 2 systems (this seems like a bad idea). I feel like I can only see the solution above that makes sense to me and I am blind to alternatives that might work as well or better.
- Am I building a way overkill system if I do not intend for net metering? Should I be looking to go smaller on the PV side and just throw a ton of batteries at this? I feel like I still need the combined inverters regardless to be able to potentially supply up to 200A.
My budget for the initial system is around $60k. This would including permitting, mounting brackets, conduit, ancillary hardware and a lot of DIY work but also paying a master electrician for final review and hookup, etc.
