diy solar

diy solar

Dual Socket Meter with two different rates


New Member
Mar 17, 2024
Hello, sorry for a long post, just trying to provide background info.

I'm planning out a new build for an all electric cabin with solar, battery, and generator backup. Currently, I’m trying to choose a main power service option that will be the most economical, while meeting my needs.

This build will be in northern Minnesota and Minnesota power is the electric company for my area.

The number one concern with going all electric is an extended power outage in the winter leading to freezing pipes. I will not be living there but will be going up often on weekends and don't live too far away. The cabin will also have plumbing that can be winterized, so in the event of a power outage, I should be able to go up and clear the lines before any damage is done. The concern is if that happens during one of the few times I am out of town or otherwise unable to go up.

So this is why I would like some kind of extended backup capability, lets say for at least 3-4 days, even though this is a pretty unlikely scenario. We have decided to not go with a gas/propane heat backup system, that decision is not entirely mine to make, there are others involved in helping fund this project who feel strongly that it should be “all electric”

For backup, I am interested in a solar system with a battery for short term backup and a propane generator to help stretch that out for longer term outages. It’s a pretty rural area so the power can end up being out for extended periods after bad storms.

The cabin will have an electric boiler, which heats the entire slab of the structure with multiple electric circulating pumps for different zones, also supplemental mini split electric heat pumps. There will be an electric induction stove, electric oven, electric water heater, well pump, dryer, steam shower, a rarely used welding outlet plus all the normal electrical appliances, etc. I don’t have an electric car but plan to at some point in the future. Given all of this, I am thinking a larger 400A total service is the way to go for my situation.

Hopefully that’s enough background just to get started with this meter decision.

Option 1: A single 400 amp meter supplying two 200 amp panel circuits. This would have one rate, seems pretty straight forward, and is something that multiple people have already discussed on the forum.

Option 2: Dual socket meter with two separate 200 amp services. Doing this lets me take advantage of the power company's dual fuel program. One of the meters will be charged a significantly lower rate than the other in exchange for the power company having the option to cut power to that meter during high peak usage times.

They offer a 25% discount on power for the ability to cut power up to 4 hours at a time, which they can do up to twice a day with a minimum of 2 hours on-time in between cuts and a maximum of 300 hours per year of cut time. The second level allows them to cut 20 hours at a time with 2 hours in between and a max of 1000 hours a year in exchange for a 50% rate cut. The standard, undiscounted rate is $0.09403 per kilowatt.

Here is the question: Is it possible to take advantage of that dual fuel setup with a hybrid solar system + battery backup + generator tie in where my heat and critical loads will be tied to the lower rate meter, while the rest of the home will be powered from the main meter, And:

  1. During normal operation when there is power being supplied to both meters and the sun is shining, The solar will charge my battery and supply its power at the higher rate meter panel, with any excess solar backloading through that higher rate meter.
  2. When the dual fuel meter cuts power to the other panel, which will have my critical loads, the battery backup will support those critical loads on that meter for the shutoff time.
  3. During an extended power outage, when both meters/panels are down, the solar, battery, and generator all support only the critical loads on the lower rate, dual fuel panel, not the main, regular rate panel.

Essentially, I would use the lower rate meter panel as my critical loads panel, even though the power company can cut power to it intermittently. But I would prefer the solar to cover power use at the more expensive rate panel and any excess solar going through the grid tie-in to be credited at that higher rate.

What I don't want is any connection between meters, I'm pretty sure it would be illegal to have it wet up where power from the higher rate meter supports the lower rate meter when they shut it down, since that would defeat the whole purpose of the dual fuel program. That is not my goal here.

I know I could just use a Powerwall style battery setup, without connection to the solar, on the low rate meter to cover those short 4 hour cutoff periods, and I could set the generator up on that system as well. But, I am hoping to find a way to let the solar panels also help keep that battery going longer in an extended outage so I don’t have to entirely rely on the generator. Reason being, I will probably only have a small propane tank for this generator and can’t necessarily count on it to keep everything going for multiple days by itself. Also, I don't necessarily need to cover those periods where they intentionally cut power, our slab heat system will hold heat for those 4 hours without issue.

I hope the question makes sense, I get that there are a lot of specifics and unknowns right now in terms of start up power and actually covering the need for critical loads, and sizing the system etc, but the solar probably wont go in until next year and the meter has to go in soon.

If it helps, the plan is to have a solar system sized to cover as much of the total home power needs as possible. Ideally, I would like to just pay a financing bill for my complete solar system and minimal electric bill on top of that.

I appreciate any advice or insights you guys have.
How much of it are you wanting to DIY and how much do you plan to farm out? Do you have any background with pushing trons?

There is a ton there in the first post and you can do as much or as little as you want. Just takes a lot of reading and learning.
Is that your total cost per KW including delivery and taxes of 9 cents? You can get that rate cut to 4.5 cents with split metering?

Get a propane generator for backup and forget solar. You will not pay off your investment for 20-25 years. Solar makes "cents" for folks in California paying 50-60 cents a KW. or for those with extra money who want a hobby.

Just my 2 cents