Help wrapping my head around my home's current wiring and options for battery backups

[json2001]

Hello - I've been watching and reading about the various solar systems everything from EG4 to Anker to Ecoflow on Will's channel and on other creator's sites and videos. Only mention that to say that everything's on the table at this stage I'm very interested in some emergency backup solutions for my home, but I need some help wrapping my head around the possible options as my home has (what seems to me at least) a more complicated than many electrical system.

I made this little diagram to show my best understanding of how my home is wired between my 3 electrical panels. To note..the "Old Main Panel" is almost completely full and is the original home's panel. The garage and basement subpanel were added with an addition to the home. The home does not (yet) have any solar panels or backup generator.


My initial questions:

1. Is it reasonable to think I would power up everything from the main panel that recieves the 2x 200amp grid service in my garage? It seems like I would lose a lot of control to prioritize certain loads at the other panels during an outtage, but maybe I just don't understand how this could potentially work between "smart panels". If this is possible it seems like it would be the most ideal as it's out in my garage, I have a ton of space, it doesn't need to look super pretty, it's right at my meter and I could hook solar and a generator input into the system from this single location. This is really the central question I'm trying to understand before moving on to any other firm plans.
   • While re-running a lot of high voltage wiring between these locations would likely be cost prohibitive, I can EASILY run CAT5 between locations.
   • Totally get that the 2 AC units would be MASSIVE energy hogs and may not end up making the "critical" cut or maybe only one of them makes the grade?
2. Is it more realistic to think I would have some kind of inverter and battery at each panel with a smart panel? For example, I would might break out a critical load sub panel at each box and then have a battery and inverter stack plugged into a transfer switch at that location?
   • If I did it this way...would I be restricting my ability to charge all batteries from solar during an outtage (given that I might not want to run solar connectors to multiple locations?)
3. For the basement subpanel - I've thought about just sticking an ecoflow or one of the anker units to plug in my network/server equipment and the chest freezer to serve as a UPS for those 2 systems. Nothing else at that panel is "critical"

I would greatly appreciate any help in understanding how to think through a system for my home's existing wiring and possible products I should look at!

 

[CaliSunHarvester]

Do you really have TWO times 200A 240V service?

 

[json2001]

Do you really have TWO times 200A 240V service?

I believe I do (at least that's what the electricians told me). It _seems_ like when they put the addition on, they just doubled the service and put the existing main panel on it's own disconnect. There's a real chance I have misunderstood the electricians, but I believe that's correct.

 

[CaliSunHarvester]

Do you have 1 or 2 meters?

 

[json2001]

Do you have 1 or 2 meters?

I have 1 meter

So maybe it's 400 amp service with each panel having 200amp?

 

[CaliSunHarvester]

I don't know.. it's probably not critical for the planning of your system. I found it's best to go by actual consumption of circuits, both peak and average per day or week.

E.g. my kitchen has 3 separate ceiling lights (3 cans, 4 cans, and another type of big fixture). With 3 separate switches, on 3 separate 15A circuits. This doesn't include under cabinet lights, which is circuit 4, but it also includes backsplash outlets.

Thanks to LED technology, those 3 ceiling circuits each consume between 30W and 60W .. that's less than an 1A each. Total overkill to have 3x 15A breakers. I sized my solar according to actual consumption, it's a lot less than I thought.

Obviously the ACs are a different animal.

 

[json2001]

I don't know.. it's probably not critical for the planning of your system. I found it's best to go by actual consumption of circuits, both peak and average per day or week.

E.g. my kitchen has 3 separate ceiling lights (3 cans, 4 cans, and another type of big fixture). With 3 separate switches, on 3 separate 15A circuits. This doesn't include under cabinet lights, which is circuit 4, but it also includes backsplash outlets.

Thanks to LED technology, those 3 ceiling circuits each consume between 30W and 60W .. that's less than an 1A each. Total overkill to have 3x 15A breakers. I sized my solar according to actual consumption, it's a lot less than I thought.

Obviously the ACs are a different animal.

That's very helpful! I think you're probably right that I can work up my exact needs for each circuit in more detail as well as even just getting some base usage info from my power bill. Thanks!

I think the heart of my question is around the fact that I have 3 panels. Is there even a reasonable way to keep the invertor (and batteries) in the single location at the garage? Or would I need units at each breaker if I needed to automatically shed some loads? I think that's the biggest current gap in my understanding.

 

[CaliSunHarvester]

I have a similar situation actually. An old main panel and cascading sub panels.

The utility input is in the upper left "POCO" and I have an offgrid solar powered panel next to it, but the output is only 10kW.

I was thinking about the same question.

Option 1) have multiple/ bigger inverters there for something like 30kW output with one centralized battery bank. That could feed not the entire property but more than half. The 3 boxes in the middle (garage, pool house, house 2) would remain on-grid.

Option 2) a second small system of 10kW output in the red marked location, which would feed the well pump and "house 3". The 2nd small system would need a separate battery bank. I found 25kWh in the 1st location adequate in recent weeks. So, another 25kWh would be needed there.

Benefit of (1) - save on batteries as maybe 40kWh would be enough for houses 1 and 3.

Benefit of (2) - decentralize things, if there is a problem with one installation, the other one probably still works.

I haven't placed orders yet, but I think I may go with (2).

 

[CRenner]

I have 1 meter

So maybe it's 400 amp service with each panel having 200amp?

Do both 200A services go through the Main panel in Garage, or does one go straight to the Old Main?
Is the main breaker in the garage a 200A or 400A?

 

[json2001]

Do both 200A services go through the Main panel in Garage, or does one go straight to the Old Main?
Is the main breaker in the garage a 200A or 400A?

Just went to verify. I have one box that is labeled "Main B" and it only has one 200A breaker - I'm nearly certain this is the disconnect that feeds the "old" panel in my home. It's right next to the Garage panel that has lots of circuits and a main 200A breaker at the top.

I have a similar situation actually. An old main panel and cascading sub panels.

The utility input is in the upper left "POCO" and I have an offgrid solar powered panel next to it, but the output is only 10kW.

I was thinking about the same question.

Option 1) have multiple/ bigger inverters there for something like 30kW output with one centralized battery bank. That could feed not the entire property but more than half. The 3 boxes in the middle (garage, pool house, house 2) would remain on-grid.

Option 2) a second small system of 10kW output in the red marked location, which would feed the well pump and "house 3". The 2nd small system would need a separate battery bank. I found 25kWh in the 1st location adequate in recent weeks. So, another 25kWh would be needed there.

Benefit of (1) - save on batteries as maybe 40kWh would be enough for houses 1 and 3.

Benefit of (2) - decentralize things, if there is a problem with one installation, the other one probably still works.

I haven't placed orders yet, but I think I may go with (2).

All good considerations! TY!

 

[CRenner]

One way of testing is to go out to the garage and turn off the main breaker, if the house stays on it is a separate system.
The basement should be off.

 

[DougfromdaUP]

I’d start gathering information with your power bill. That will tell you average usage.

My power company will also provide useage in kWh per 15 minute period. That will tell you the peak usage and maybe give you some insight into your power consumption.

 

[CaliSunHarvester]

if OP is looking to put only selected circuits on a solar powered panel e.g. with a transfer switch, then the information from the bill is not detailed enough. OP will need to measure circuit by circuit. Maybe not every light, but definitely the big appliances like AC, furnace, water heater, pumps, fridges, ovens. There's a big difference between old and new appliances. I read just a few days ago that someone's fridge pulls on average 300w which came to 24*0.3 = 7.2kWh per day.
In contrast, our side-by-side 36" fridge from 2016 only consumes 1.5kWh per day, and it does get opened many, many times every day.
I measured the fridge with a kill-a-watt type plug over a 7 day span.
For big appliances there are power meters like this:

https://www.amazon.com/Current-Amperage-Voltmeter-Multimeter-Transformer/dp/B07JB9B2QL/ref=mp_s_a_1_6_sspa?adgrpid=57596298404

There's a complete solution from Emporia, but it didn't fit in my panel, and also, I thought it was overkill for me.

 

[wsaharem]

I’m doing something similar. I have 1 main panel and 3 sub panels. In Texas, new homes have 240 breakers outside, so all our big loads including the 3 sub panels are all served from the main. So I’m creating a new critical load panel just for the backup and moving just some key things to it. (2 of the sub panels and 1 5 ton AC and one mini split for the garage which will house the inverters). I’m assuming your sub panels are served from your main also? I’m spending a lot of time watching my usage on Emporia Energy (interesting stuff) so that I can truly balance the load correctly. I’m also adding bypass switches for the inverters just in case. My backup will be batteries plus generator, maybe solar added later.

 

[CaliSunHarvester]

So I’m creating a new critical load panel just for the backup and moving just some key things to it.

That's what I did initially. Then I realized how little power most circuits use.. I ended up moving everything from the old main panel except electric floor heaters, hot tub and double wall oven. My solar panels generate more than enough to add one of these 3, perhaps 2, but it would/ could be a strain for my 10kW inverter:



(Those spikes in the chart are the old style water heater which I will replace with a heat pump model.)
Floor heaters haven't been used in over 10 years, electric oven only 1x since installing it in 2016 - and I burnt that pizza, so it's back to the gas oven. Remains the hot tub. Which is currently off. Unfortunately demand for the hot tub is mostly in winter, not exactly peak solar time.

Yeah, I should have gotten a 15kW inverter. Maybe when the wh is replaced, I can add the hot tub.

 

[CaliSunHarvester]

I’m doing something similar.

Just saw your charts. 27A for the dryer!!
I replaced our 1980 dryer with a heat pump dryer. It pulls only 2A (two Amperes) per leg. That's about 500W. In fact, most of the time I saw a number under 2A.

Just imagine how much more you can put on solar if you cut that dryer from 27A to 2A. It runs a bit longer, as much as 2x as long, but the savings are still huge.

 

[wsaharem]

Just saw your charts. 27A for the dryer!!
I replaced our 1980 dryer with a heat pump dryer. It pulls only 2A (two Amperes) per leg. That's about 500W. In fact, most of the time I saw a number under 2A.

Just imagine how much more you can put on solar if you cut that dryer from 27A to 2A. It runs a bit longer, as much as 2x as long, but the savings are still huge.

View attachment 202179

Yep, wasn’t happy about that, so it clearly stays out of the critical load! LoL. (We debated gas versus electric heater when we bought the house. Regretting the electric choice!

 

[CaliSunHarvester]

Yep, wasn’t happy about that, so it clearly stays out of the critical load! LoL. (We debated gas versus electric heater when we bought the house. Regretting the electric choice!

Just do the math how long it takes for a heat pump dryer to pay for itself. We save something like 15kWh a week or 780kWh a year.. that's almost $500 saved per year in our area. The unit cost $1000. A conventional dryer is $500.

Slower break-even outside California.