How many additional solar panels to charge the Cybertruck?

[Sdpluth]

We need to add additional solar panels and trying to get an application in before the new net metering changes here in California. I want to try to future proof our needs and I am not sure if there is a way to estimate how many additional panels will be needed for the Cybertruck. Without knowing the actual specs it is a WAG but I was hoping someone could lend some expertise that might get me in the ballpark.

I found the calculation guide below for estimating, does it sound reasonable (assuming 2 motor version and 12,000 miles driven annually)?


A good rule of thumb to use is that an EV will use about 1 kWh per 3 miles driven. For example: if you drive 12,000 miles per year, and you charge up primarily at home, the EV will need about 4,000 kWh/year.

(12,000 miles/year) x (1 kWh/3 miles) = 4,000 kWh/year

Once you figure out how much electricity you need to produce, let’s convert that to solar panels.

Under ideal conditions, 1 kWdc of solar panel capacity will produce about 1,478 kWh per year in the San Diego area.

So here’s how to calculate how much solar we need to produce 4,000 kWh in a year:

(4,000 kWh/year) / (1,478 kWh/year/kWdc) = 2.7 kWdc

Rooftop solar panels these days have a capacity of about 330 Watts each. In conclusion, you would need about 9 extra 330W panels to get 2.7kWdc of extra capacity.

(2,700 Watts) / (330 Watts/panel) = 8.2 panels = 9 panels

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[Ogre]

I think your calculations look good, might be a few kWh more or less, but close enough anyhow.

I assume the Cybertruck will be replacing an ICE vehicle? Because if you are replacing an EV or adding an additional car calculation is off. Because the number of miles you drive won’t increase in either case.

 

[SolarWizard]

In san diego we go with 3.5kW per ev driven 15k miles and it works out great unless they are north in which case, 5.5kW
Am I right in assuming you’ve already had your contractor out and have a one line diagram done?
If not you should dm me on how to beat the deadline because odds are XYZ solar company wont. SDGE has to have your system in at least stage 2 review by close of business 4-15

 

[NJturtlePower]

We need to add additional solar panels and trying to get an application in before the new net metering changes here in California. I want to try to future proof our needs and I am not sure if there is a way to estimate how many additional panels will be needed for the Cybertruck. Without knowing the actual specs it is a WAG but I was hoping someone could lend some expertise that might get me in the ballpark.

I found the calculation guide below for estimating, does it sound reasonable (assuming 2 motor version and 12,000 miles driven annually)?


A good rule of thumb to use is that an EV will use about 1 kWh per 3 miles driven. For example: if you drive 12,000 miles per year, and you charge up primarily at home, the EV will need about 4,000 kWh/year.

(12,000 miles/year) x (1 kWh/3 miles) = 4,000 kWh/year

Once you figure out how much electricity you need to produce, let’s convert that to solar panels.

Under ideal conditions, 1 kWdc of solar panel capacity will produce about 1,478 kWh per year in the San Diego area.

So here’s how to calculate how much solar we need to produce 4,000 kWh in a year:

(4,000 kWh/year) / (1,478 kWh/year/kWdc) = 2.7 kWdc

Rooftop solar panels these days have a capacity of about 330 Watts each. In conclusion, you would need about 9 extra 330W panels to get 2.7kWdc of extra capacity.

(2,700 Watts) / (330 Watts/panel) = 8.2 panels = 9 panels

Close enough it sounds to me, but ultimate solar output and efficiencies vary greatly by your physical location, climate and panel/array orientation.

Does your current inverter (or inverters) have available capacity or would this require adding a new one?

That's where costs between hardware and install can be cost prohibitive for add-ons for some systems.

My inverter is a SolarEdge 11,400w singe unit which can occasionally peak out on the best of spring days with our 12,350w total max output panel arrays, so we could add very little without an extra inverter at very least. 38x 325w panels = 12,350w or 12.35kW

Here in NJ the other factor would be what are you ALLOWED to install based on utility rules. They only let you install up to a certain estimated percentage above your typical annual usage basically so you don't make your home a massive income power plant between both net metering and state solar credits. They did allow some estimation at the time as I had already taken delivery of my 1st Model 3 in 2018, but hadn't had it for a full year when we finalized our solar plans.

The incentive were and still are pretty good here. You double dip by offsetting your usage month-to-month but also earning what were called SREC's (Solar Renewable Energy Credits) for every 1,000 kWh generated which you then sell at a market rate at your discretion. This program continues for the first 10-years of operation under my program...used to be as good as 15-years.

As mentioned we have a 12.35 kW non-Tesla solar system that went live Sept. 2019. We generate 14,000+ kWh annually and earn 14 SREC's which I've been selling at an average of $220 EACH. You can see how the ROI comes quick in this scenario... 100% offset and banking kWh's with my utility 7-8 months a year where we get only a $3.25 customer connection charge monthly, burn up our kWh bank another 2-3 months and get a small bill of $40 or less usually in Dec. to Jan. during our worst solar months.

Our current setup offsets our home (2,400sq. ft.) and my Model 3 charging for about 10k miles a year. So if and when I swap to the CT I don't expect much of a change in usage, although we still have one ICE, a 21' Telluride that might get swapped for a Kia EV9 if I can convince the wife.

 

[S.H.Peterson]

Maybe Im talking out of school here, forgive me if I am.
I would also have a LNG/propane backup genny system like Generac.
The sun wont always shine and at least you would have the backup of instant power on demand.
Yes, its more $, but I was thinking of TOTAL independance options.

 

[Jhodgesatmb]

It doesn’t seem right to me. We have a 4 Kw array for the home and on a good day it produces 30 KwH of power. The house uses 22 KwH on average. Per day.

Our cars both use, on average, 80 miles per day, which is about 25% of the battery pack size (-75 KwH). Let’s say 20 KwH per day to be conservative. Let’s say that a CT is half as efficient overall so that it needs 40 KwH to go the same 80 miles. Then you would need a 6 Kw array just for the CT and, for us, an additional 3 Kw for our house. That Assumes ideal conditions, which do not exist where I live. Our array uses older panels and is 27 panels for 4 Kw. I am spitballing that you would need more like 30 additional oanels

On top of that, you cannot charge a car directly from solar (unless you want to charge and not drive, or you drive at night), so you need a battery to store the power and you need to be able to store all of that 40 KwH in a battery. If the batteries can store around 10 KwH you would need 4 batteries and they would fill and discharge every day that you use the truck.

This is an off-the-cuff evaluation but is wildly different than what you say, so where am I mistaken? I keep telling friends and family that you cannot effectively charge BEVs from solar but I appear to be in the minority.

 

[Jhodgesatmb]

Maybe Im talking out of school here, forgive me if I am.
I would also have a LNG/propane backup genny system like Generac.
The sun wont always shine and at least you would have the backup of instant power on demand.
Yes, its more $, but I was thinking of TOTAL independance options.

We have a 22 KwH whole home Generac. We sized it so that we could charge the cars (one at a time) if the power cuts (which it has, a lot, this year). I think it is a good option but quite different from the original question,

 

[NJturtlePower]

Maybe Im talking out of school here, forgive me if I am.
I would also have a LNG/propane backup genny system like Generac.
The sun wont always shine and at least you would have the backup of instant power on demand.
Yes, its more $, but I was thinking of TOTAL independance options.

My ONLY regret in my solar journey has been not adding Tesla Powerwalls along with solar. Especially now that the Federal energy incentives are back up to a 30% credit, Powerwalls come out likely cheaper than whole home gas or propane options dependent on sizing and needs.

https://www.energystar.gov/about/federal_tax_credits/battery_storage_technology

We don't lose power often, but its super frustrating when its a sunny clear day and the solar is completely dead when the grid power is down.

We have Natural Gas for heating, cooking, dryer, etc. so a whole home generator on gas is an option, but that also comes with added expenses and permitting issues that are not in play with Powerwall's such as where they can be installed, a concrete pad, annual maintenance and operation expenses.

I would love to throw a pair of Powerwall's in my basement next to my solar hardware and have a self sufficient eco system.... charging PW's during the day off solar, using them for offsetting usage at night on TOU energy plan or during outages, all while being able to keep my solar active regardless of the grid status.

Tesla discontinued PW sales without a full solar install for years now, but just opened orders back up so now I'm impatiently waiting for my number to get called.

https://electrek.co/2023/03/10/tesla-opens-direct-powerwall-orders-again/

 

[S.H.Peterson]

I very MUCH hope it works out for you and you can get it !

 

[SolarWizard]

It doesn’t seem right to me. We have a 4 Kw array for the home and on a good day it produces 30 KwH of power. The house uses 22 KwH on average. Per day.

Our cars both use, on average, 80 miles per day, which is about 25% of the battery pack size (-75 KwH). Let’s say 20 KwH per day to be conservative. Let’s say that a CT is half as efficient overall so that it needs 40 KwH to go the same 80 miles. Then you would need a 6 Kw array just for the CT and, for us, an additional 3 Kw for our house. That Assumes ideal conditions, which do not exist where I live. Our array uses older panels and is 27 panels for 4 Kw. I am spitballing that you would need more like 30 additional oanels

On top of that, you cannot charge a car directly from solar (unless you want to charge and not drive, or you drive at night), so you need a battery to store the power and you need to be able to store all of that 40 KwH in a battery. If the batteries can store around 10 KwH you would need 4 batteries and they would fill and discharge every day that you use the truck.

This is an off-the-cuff evaluation but is wildly different than what you say, so where am I mistaken? I keep telling friends and family that you cannot effectively charge BEVs from solar but I appear to be in the minority.

Not sure where you live but there are places around san diego that get as much as 1700 sun hours a year with good roof orientation

And there are definitely direct solar charging solutions on the market. The solar edge energy hub system offers pv only smart charging (even in a grid down scenario) and if he beats the deadline, SDGE offers 1-1 net metering under NEM 2.0 so at least the credits would be solar based for overnight charging.

 

[Gurule92]

I have a relatively small roof so I just maxed out the amount of panels lol. My net metering is pretty good and we dont have any peak rates yet, but my bottleneck is my inverter.

My solar journey is one that couldve turned me into a solar supervillan but it worked out eventually.

Man, I rly wish we got the kinda sun you guys get though lol my roof faces north/south so im extra unlucky.

I'm about at the end of my billing cycle and have a net use of about +226.19 kwh. A good sign overall considering we still arent getting a whole lot of sun.

 

[JBee]

If you want a half decent calculation of what extra solar you need for your specific location, you can use this to draw a rectangle around your house, then orientate the PV and calculate what you need.

https://pvwatts.nrel.gov

ABRP has dual motor at 450Wh/mile, so you will need around 5500kWh per year, excluding losses, for 12,000miles.

 

[Ogre]

Maybe Im talking out of school here, forgive me if I am.
I would also have a LNG/propane backup genny system like Generac.
The sun wont always shine and at least you would have the backup of instant power on demand.
Yes, its more $, but I was thinking of TOTAL independance options.

Meh. On those days, you can always stop at a supercharger and plug in on those days. That’s a big investment to avoid stopping at a super chargers once every couple of years.

OP is in California, not Seattle.

 

[RandyS]

I think your calcs look reasonable, but since you are trying to beat the deadline for NEM 3, I would go a step further. Within reason, why not install more panels if you have space on your roof and fill it up or at least maximize the "Good space"? You won't have a second chance to do this under NEM2 in the future, so if you add another EV or anything else that consumes more energy I would look forward a little bit and install a bit more than what the CyberTruck will consume. I went from 24 panels to 41 panels a couple of years ago, and I wish I had a few more panels now...Maximize it!!!! This is your chance!!!

 

[S.H.Peterson]

Meh. On those days, you can always stop at a supercharger and plug in on those days. That’s a big investment to avoid stopping at a super chargers once every couple of years.

OP is in California, not Seattle.

I was angling more at TOTAL energy indepence. You have the capacity to not rely on ANYONE for electrical power.

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