Building a new house -- What would you use?

[Phone_Harold]

Will,

First time posting to the Forum!

I am in the process of building a new house, and I want to install solar day one with battery backup. So I want to get some opinions about the build.

The House I have faces west. The only clear view of the sky is south and west. The system has to be roof mounted as I do not have a place for a ground mount system. The house is 2,600 square feet and is located in Northeast Oklahoma. I estimate no solar exposure until 11 am. Our summer electric rates using time of day pricing are $ 0.15 peak and $ 0.09 off-peak.

I will have one Main Panel at the Minimum Point of Entry for the electrical system. On it, I will have breakers for 3 220 Outlets in the Garage for future EVs, 1 breaker for Electric Dryer, 1 breaker for the 'Medium' loads, 1 breaker for 'Protected' loads, and 1 breaker for Protected Loads bypassing Inverter. At the Inverter, there will be a switch to bypass the inverter. For the Furnace, I will have a light switch so it could be fed off the 'Medium' loads panel in the summer or the 'Protected' load panels for Natural Gas heat in the winter. I want Solar to work in the case of power loss as we can have multiday power outages

1 -- Small System with a 3KW inverter, two EG-4 batteries for 10KW of backup. The inverter will cover Lights, TV, Freezer, Residential Frig, and limited outlets. No 240v capability. May have a manual interlock for energizing the 'Medium' loads panel. Shooting for 2 to 4 KW of solar.
2 -- Medium System with a 6KW system with 220v for one or two 'Mr. Cool' like heat pumps to use when power is out, and all outlets covered. I will have the manual interlock for energizing 'Medium' loads panel. Shooting for 4 to 6Kw on the roof. Plan to have four EG-4 batteries for 20KW of backup.
3 -- Large System with 12Kw Inverter covering the entire house and 5 tons of AC. I would exclude EV charger and Dryer. Plan to have 6 to 8 KW on the roof. Plan to have four EG-4 batteries providing 30KW of backup.

For the Small to Medium system, I am looking at Victron with the flexibility and management of all the components.

I would like to use a Sol-ark in the medium or large system, and use the 'back feed' option to cover the high loads and possibly do net metering with the Utility. My utility requires time-of-day pricing with peak between 2 pm and 7 pm with all other hours as off-peak. Not sure I want to cycle the batteries to shave off-peak pricing with a pricing delta of 8 cents. Because of my orientation, I would like to have more than two charge controllers so I do not have to put the panels in series. I could do series-parallel, but having 30 amps, I do not know the size of wire I will need.

I do like the 'David Poz' solution of two 240v 5K inverters with an autotransformer, however, the Growwats are not very efficient nor can I do back-feeding and/or net metering, and I do not know if I can pass electrical inspection. Would MPP be a better choice?

If you were to build a system like this, what would you do? Are my systems too small or too large? (I do not have good usage data on my loads, so one's experiences would be helpful!) Any input on Solar Panels since the available roof area is limited is also appreciated?

It is not often one can install a Solar System on day one on a new house!

Harold.

 

[TRW]

This would be a fun link to follow, even better would be if Will could tell us precisely what he would do with his own home system if he started over. He has so much experience and knowledge and he updates every day! He is able to power everything, including direct charging his Tesla. No matter what I hope this link takes off. Even more fun would be links where he would purchase.

 

[TRW]

There are many on this forum, that can answer your questions, but you addressed it specially to Will, so others are not weighing in.

 

[Phone_Harold]

I meant to say Will and Company so anyone can chime in.

 

[TRW]

Here is a new video from Will, that will tell you a bit of interesting info that is brief and simple.

 

[Phone_Harold]

TRW, thanks for the recommendation.

 

[Hedges]

Grid-tie PV can be done for about $1/watt not including labor (e.g. DIY). That works out to $0.05/kWh over 10 years, $0.025/kWh over 20 years if nothing need replacement.
Battery systems will cost more. DIY LiFePO4 cells will cost $0.05/kWh by the time they wear out, if they last as long as hoped. Add inverter, etc. to price.

I like AC coupled PV, oversize PV and undersize battery (in my case, grid backup so rarely depend on battery.)
I'm using SMA, which works well. Battery inverters surge to almost 200% for 3 seconds, and PV inverters deliver power during the day.

From what I've read, SolArk is good, and supports AC coupling to GT inverters which would be a way to go beyond its 9kVA inverter capability.

 

[TRW]

Will Prowse has done many videos, but I still think he could endorse a grid-free system that includes 100 percent of the package exactly how he would do it for himself. That alone would be so helpful to us handy people who are striving to get a good system, and Will's insight into reliable equipment.

If any of you know who to get this suggestion to Will, please do it!

 

[time2roll]

I would go big and get a solar roof system. Kills me a bit to buy a roof and cover with panels. There are some options besides Tesla.

 

[Phone_Harold]

Got one here in town advertising non-Tesla roof shingles.

I thought there were very inefficient, and a pain when they fail.

Is there anyone with experience with roof shingles?

 

[OzSolar]

Got one here in town advertising non-Tesla roof shingles.

I thought there were very inefficient, and a pain when they fail.

Is there anyone with experience with roof shingles?

Yes they are inefficient and a pain when they fail.

My opinion.... I'm old school so keep that in mind.

Roofs should be roofs and solar panels should be solar panels. EG: When your solar shingled roof leaks do want to call the roofer or your solar guy? What about when your solar shingle does something that makes your inverter fault out and crash the whole system? Again, are you calling the roofer or the solar guy that didn't install it?

I've been in the trades for a fair bit and can state that any chance one trade gets to blame the other for the problem they'll take it. The customer loses big time is the main result.

 

[Phone_Harold]

I understand that. It is a big issue in the Telecom world too.

 

[TRW]

If you have not got a roof in place yet, a standing seam metal roof is the way to go if you are willing to put panels on it. That would be my choice.

 

[Calsun]

I looked into the cost of a Tesla power wall for my house and the cost was roughly the same as installing a standby generator. Key difference is that the power wall would provide power for at most two days whereas the natural gas powered generator can run indefinitely.

Spec out the batteries that will work with whichever new generation of inverter you buy. My Solis 5G has a limited number of batteries that are compatible.

Be aware that the electric and fire codes are out of date when it comes to lithium battery backups. A Tesla Mega Bank caught fire last year at Moss Landing and the area was evauated as the fumes are toxic and the highway was shut down. The only safe approach with something like the Tesla power wall is to have it outside the building envelope and enclosed with fire proof material. Good idea to have a gas detector inside the house and to block and subfloor vents near the power bank (same as is required for a gas generator).

I have a natural gas source that is reliable but if that had not been the case I would have got a propane powered generator and had the local propane dealer install a large LPG tank. Want the tank at half full amount to be able to run the generator for 3-5 days.

Many companies are making inverters that have 4 MPPT charge controllers which allows for a lot more flexibility to have multiple arrays of different outputs. For a new house I would check one of the online calculators to determine the best tilt angle for the panels and then have the pitch of the roof set to match that angle. It will make is easy to get maximum output from the panels.

I would look for a good electrical contractor with solar experience to do the wiring layout for the house and not use a sub from the general contractor or builder.

 

[Johneb]

Outback inverter.

 

[kendive]

Key difference is that the power wall would provide power for at most two days whereas the natural gas powered generator can run indefinitely.

I know it's an old post but I would have to disagree with this statement. I worked in the oil field as an chief electronic tech for a very long time and even the 11kV MAN, CAT, Wabtec, etc... Diesel Engine Generators we ran all the time need to be shut down for maint. Those cheap air cooled junk whole house generators are not going to last very long on continuous use.

I would rather have solar and batteries. But each there own. But I would not own anything from Tesla.

 

[hautions11]

I am far from an expert on any of this, but I am 8 months in to building a house and this is what I did.

1900 ft upstairs 100% spray foamed
1100 walk out basement, ICF foundation

I wanted to power the whole house, grid tied. Indiana gives zip for selling power, so I skipped it.

Solark 15k runs one 200 amp panel
400 amp service
2nd 200 amp panel is mostly non essential 220 and a few random 110 circuits.

My electricians installed it all for 5-6 hours. Fully inspected and bought off

30 kWhr server rack

South and SW standing seam room will have 20 450 panels. I may add 8 more in a ground mount. I do not get sun until 10:30 in the summer. Winter will be shaded through leafless trees. Again I am no expert, but my experience is similar to yours. Fire away!!

 

[hautions11]

Maybe I should start a thread in this area, rather then general discusion

 

[Madcodger]

I am far from an expert on any of this, but I am 8 months in to building a house and this is what I did.

1900 ft upstairs 100% spray foamed
1100 walk out basement, ICF foundation

I wanted to power the whole house, grid tied. Indiana gives zip for selling power, so I skipped it.

Solark 15k runs one 200 amp panel
400 amp service
2nd 200 amp panel is mostly non essential 220 and a few random 110 circuits.

My electricians installed it all for 5-6 hours. Fully inspected and bought off

30 kWhr server rack

South and SW standing seam room will have 20 450 panels. I may add 8 more in a ground mount. I do not get sun until 10:30 in the summer. Winter will be shaded through leafless trees. Again I am no expert, but my experience is similar to yours. Fire away!!

Looks great! Does the Ronk switch allow you to select either grid or Solark to that first panel? And if so, does the large box/panel on the far right just provide a means of connecting the grid back to the SolArk? Thanks.

 

[hautions11]

Looks great! Does the Ronk switch allow you to select either grid or Solark to that first panel? And if so, does the large box/panel on the far right just provide a means of connecting the grid back to the SolArk? Thanks.

Yes the Ronk bypasses the Solark if it has an issue. The large box on the right is just space to take the incomming service and split it. I have a picture.

I am setting up the batteries this week.