Solar Panels and Battery Backup

[Fmc]

I know there are heaps of variables. But I am considering solar at my house. La has no time of use and net metering is at wholesale and not retail price. I drive roughly the equivalent of 10 powerwalls. Is battery backup for solar necessary for outages when you have a Rivian to get through an outage for a day or two?

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[ndmiller]

If you have natural gas connection get a home generator, cheaper and more reliable, especially since the use case is small.

 

[SANZC02]

I know there are heaps of variables. But I am considering solar at my house. La has no time of use and net metering is at wholesale and not retail price. I drive roughly the equivalent of 10 powerwalls. Is battery backup for solar necessary for outages when you have a Rivian to get through an outage for a day or two?

Without a battery backup your solar will not work during a power outage.

As of today, the only way to use the Rivian is the 1500 watt 110 outlet, probably not enough during an outage. They are working on VtoH but no timeline has been provided.

 

[Khaneric]

So one thing you could do is use an intermediate battery system that can output 240v and charge with 120v at the same time. This way you could hook your battery (batteries) up to to the house and plug the battery charging cable into your Rivian and limit the charge rate to 1500w.

You really have to read the fine print of each battery system though as some don't let you do 240v and 120v at the same time.

You would also need a separate non grid tied solar system if you wanted to use any solar.

In theory though, you could charge the battery with solar during the day, and run off the truck via the battery at night until the truck dies.

 

[Mathme]

I live up in the Bay Area and have solar with a Battery Backup..battery backup is the way to go. Although you can have enough battery packs (they come in 9.9kWh bundles) you typically won't for cost reasons (they are still pretty pricy). The general recommendation is to go with one bundle for your 10kWh and then when the prices drop over time, it is easy to add extra batteries.

When the power goes off, you essentially become your own little power grid and the general idea when with a battery backup is to have enough electricity to run critical services over night . Once the sun comes up, the solar panels will recharge the battery and then any outlets that are on the backup systems.

When you install the system, the electricians will add another panel to your existing house...and only those circuits in that panel will run on the backup power. When we installed our system, we had our Refrigerator upstairs, and some outlets in the kitchen put on the system. When we remodeled (and since the walls were open), the electrician added our spare refrigerator all overhear lights in the house, instant hot water, and furnaces (water and furnaces are gas and only need electricity for the electronics and the blower).

You'll hear a lot of noise about Tesla Systems in the solar industry - they are an outspoken leader. Whatever system you go with, you'll have inverters on the back of each panel, the brains to the system, and then the battery and associated brains. Tesla usually out-sources these different components to different vendors and when there's an update to one system, there's a chance it may affect another (think a Windows update on a computer). We went with a company called Enphase (also a big one in the industry) that's based in the Bay Area and they make all of the main components involved in the systems, so when you update, they all work together (think a software update on a Mac as a difference).

Since we got our system 4ish years ago, Enphase has also come out with a Level 2 EV charger. If/when our current charger dies, I'll go with the Enphase EV charger as it is designed to talk to the overall system and once the solar system is fully charged, the system will use excess energy (that you would have otherwise sold to your electric utility) to charge your EV. In our system with 23 panels, we make a max of about 6kWh of energy an hour on a bright sunny day...in that case I'd rather take my excess solar energy to charge my car, than sell the power to the utility, only to buy it back again.

About 1.5 years ago, we lost power for three days and with battery backup, we had lights, heat, hot water, ice cold refrigerators, the built0in coffee machine (there are priorities), outlets in the kitchen, and because of the way the kitchen is wired we even can use the dishwasher. Not too bad overall

There are lots of ways to go solar and I highly recommend it. Check Around for some solar brokers as we also found a financing plan that was:
$0 down,
0% interest, with a 25 year term
25-year warranty on system components.

We decided to use their money for the major upgrade to our house.

 

[MDH]

I know there are heaps of variables. But I am considering solar at my house. La has no time of use and net metering is at wholesale and not retail price. I drive roughly the equivalent of 10 powerwalls. Is battery backup for solar necessary for outages when you have a Rivian to get through an outage for a day or two?

I have a 12kW Tesla Solar and 3 Powerwalls. I drive a R1T and Y. I suggest you purchase the largest solar system you can afford and your roof will allow. However don't go solar without battery back-up. Selling power back to the grid at wholesale is no bueno. Rivian and Tesla are supposed to have V2H this year but who knows when it will actually materialize. I want more storage but will wait to go V2H.

Approximately nine months a year my power bill is $19/month, the grid tie-in minimum. When it snows or an outage lasts more than a few days, I'm stuck. Then a nat gas generator has a big advantage.

You will love home-charging the Rivian for free. Vampire drain will be of little concern.

 

[Fmc]

Thanks for all the input. I have been creating my own V2H using an Anker battery plugged in to the R1 and the other end plugged into a transfer switch on my house.

 

[iansriv]

It all depends on how much you want to spend. The cheapest solution is to just get a grid-tied system without batteries. I read that Rivian is close to a V2H charger. That would make the R1 a standby for emergencies. The next solution is what others have pointed out which may be an off-grid system with batteries. This would allow you to be fully functional during an emergency and tie the Rivian in (as you are doing) through the battery system. I am in the first category and waiting for a proper battery system to go off-grid. My system generates enough for the house and R1 but I lose the value because of the buyback rates. Cheers.

 

[PaythePiper]

I have a 12kW Tesla Solar and 3 Powerwalls. I drive a R1T and Y. I suggest you purchase the largest solar system you can afford and your roof will allow. However don't go solar without battery back-up. Selling power back to the grid at wholesale is no bueno. Rivian and Tesla are supposed to have V2H this year but who knows when it will actually materialize. I want more storage but will wait to go V2H.

Approximately nine months a year my power bill is $19/month, the grid tie-in minimum. When it snows or an outage lasts more than a few days, I'm stuck. Then a nat gas generator has a big advantage.

You will love home-charging the Rivian for free. Vampire drain will be of little concern.

19/month, but what did your system cost you?

 

[R.I.P.]

If you have natural gas connection get a home generator, cheaper and more reliable, especially since the use case is small.

Natural gas backup power in earthquake country... ?

 

[Dave Cundiff]

Natural gas backup power in earthquake country... ?

It's possible to get "earthquake valves" which shut off the gas flow when earthquake-type motion occurs. I know they put them on propane tanks. I don't know if they fit into natural gas lines.

Best wishes!

 

[Mark_AZR1T]

I have a 12kW Tesla Solar and 3 Powerwalls. I drive a R1T and Y. I suggest you purchase the largest solar system you can afford and your roof will allow. However don't go solar without battery back-up. Selling power back to the grid at wholesale is no bueno. Rivian and Tesla are supposed to have V2H this year but who knows when it will actually materialize. I want more storage but will wait to go V2H.

Approximately nine months a year my power bill is $19/month, the grid tie-in minimum. When it snows or an outage lasts more than a few days, I'm stuck. Then a nat gas generator has a big advantage.

You will love home-charging the Rivian for free. Vampire drain will be of little concern.

This is solid advice. We have 20kW of Tesla solar and three (3) Powerwalls. Living in AZ we produce enough energy to keep both Rivian's charged to 70% and the house off-grid power 24/7. About 45 days in the summer we will have to use 50% solar and 50% grid to keep vehicles charged (11pm 6 cents kWh).

We're huge solar proponents with battery back up. If you're not staying in your home for 7+ years, then the ROI doesn't work, but for us it's a no-brainer. Our electricity price will remain fixed for the life of the system (give or take). We almost never use our central AC, as the house is fully inverter mini-split units, including the garage and storage. Modern tech.!

 

[md2023]

We have a 12.96 system with one powerwall battery. It works well, but we would benefit from another powerwall (and I am told adding another battery is not particularly easy). The system produces about 70-75% of our power (in Massachusetts) yearly - great May-Sept, not so good Dec-March (our house positioning is good but not great). It will take about 8-10 years for pay back but worth it to us from an environmental perspective. The battery wall has worked seamlessly during outages (and can be manipulated to reserve power for upcoming storms) - though we don't have many.
If I want to charge the R1T at top speed (at 48 amps), I need a full powerwall and bright sun.

 

[R.I.P.]

It's possible to get "earthquake valves" which shut off the gas flow when earthquake-type motion occurs. I know they put them on propane tanks. I don't know if they fit into natural gas lines.

Best wishes!

... exactly. Because gas lines break during significant seismic activity.

No gas, no backup power. Not a great backup plan for earthquake country.

Done properly, a good battery+ solar is more likely to survive to continue providing power.

 

[BigSkies]

I’m in the process of getting solar myself in Colorado.

Solar seems very worth it with CA utility rates. I suspect a battery is also worth it given my surface-level understanding of CA’s new net metering rules.

The battery is less for outages and more for managing net metering pricing. Although it would be nice for outages as well.

Talk to installers about the cost of a system with and without batteries. The new version of Tesla’s Powerwall comes with a built-in string inverter, so it avoids some other system costs. My system designed with and without a battery involved different design decisions around inverters, panel size, and panel manufacturer.

The battery version of the solar system actually ended up being about the same price as without a battery. Although there were some other differences in the system, and my utility is heavily incentivizing batteries.

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