Tesla Hacker Jason Hughes Reveals His Impressive Solar/Battery Home

SEP 15 2016 BY MARK KANE 60

Jason Hughes, also known also as wk057, who from time-to-time uses his hacking skills to experiment with Tesla cars, shared his insights after the first year of owning a 44.4 kW off-grid solar system.

44.4 kW off-grid solar system - wk057

44.4 kW off-grid solar system – wk057

Earlier Hughes discovered sign “P100D” embeded in the Tesla 7.1 firmware and also works on Tesla drive units in his spare time.

The solar PV system is combined with an energy storage system – perhaps not surprisingly build from Tesla Model S batteries.

Electricity is used both for the house and for two Tesla Model S.  It is clearly not an economical option, but rather a proof of concept.

Despite the installation was designed to be off-grid, sometimes there still was a need to use electricity from the grid.

Some details on the project (via: wk057’s SkieNET)

“As of noon today my house has been powered primarily by my off-grid solar setup for one full year (a leap year, too).  In celebration, I figured I would share some aggregate stats from the past 366 days. :)

  • 43,929 kWh generated by solar array and utilized (Average 120 kWh/day, usable AC power)
  • 20,576 kWh discharged from the batteries
  • 114 equivalent cycles on the storage batteries
  • 11,259 kWh used for Tesla Model S charging (over 33,000 miles)
  • Best production day: 2016-03-21 @ 260.7 kWh (Charged three Model S that day)
  • Worst production day: 2016-01-22 @ 0.02 kWh (All panels covered in several inches of snow)
  • On 222 out of 366 days (60.7%) the storage batteries reached full capacity before sunset and some amount of incoming power was wasted.
  • 703 kWh bought from the grid (1.6% of total usage) :( Some reasoning behind the switch-to-grid events:
    • November 2015 – First shortage due to 9 straight days of bad weather.  Power needed for driving.
    • December 2015 – Two grid usage events needed for driving power. Cold weather caused significant power usage.
    • January 2016  – Snow and bad weather caused little to no generation for an extended period.  Preemptively switched to grid power for a couple of days to keep reserve in battery bank in case of grid outage.
    • February 2016 – Above average driving power needs during moderate bad weather period.
    • May 2016      – Error in custom predictive algorithm caused a switch to grid power with 25% SoC remaining, resulting in about 40 kWh of unneeded grid use.
    • July 2016     – Error in custom predictive algorithm caused a switch to grid power with 25% SoC remaining, resulting in about 30 kWh of unneeded grid use.

Suffice it to say, it’s been a great year.

Something to keep in mind is that my generation numbers can not take into account power that would have been generated on the 222 days where the storage batteries reached full capacity and all incoming power was not utilized.  A goal for this year is to put that excess/wasted power to better use.  Rough estimates would say that I’ve wasted somewhere around 15 MWh of power over the last year due to this.  This is not a bad thing, generally, since it means I’ve made enough power for my needs and is part of having an off-grid system.  Would be nice to do something productive with that power, though.

The cycle wear on my storage batteries comes out to the equivalent of about ~29,000 miles of driving in a Model S.  It worked out to a bit more cycling than I would have preferred.  Some of this is due to needing to charge one or both of my household’s Model S in the morning before sunrise in order to have power for driving during the day when the car isn’t going to be at the house to charge.  Also, some of the cycling happened prior to the creation of my interface that keeps the Model S charge rate equal to incoming solar power when a fast charge is not required… resulting in no cycling of the home storage pack.  Overall, I expect the next 12 months to have less cycling.

Also, my home is fully electric.  Electric heating and cooling (air source heat pumps).  Electric cooking.  Electric vehicles.  No natural gas, oil, etc.

For year one, I think having 98.4% of my power come from my own little power plant definitely makes it a successful year.”

source: wk057’s SkieNET via Teslarati

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60 Comments on "Tesla Hacker Jason Hughes Reveals His Impressive Solar/Battery Home"

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Wow. Just wow.

Nice! where does he live exactly?

I saw Duke Energy on the bill and thought NC as that is where I live but the link on top of the bill confirms it.

My HOA prohibits solar panels on roofs…

“My HOA prohibits solar panels on roofs…”

Many states have laws that make such terms unenforceable. You might want to check if your state has such a law. And if it doesn’t, ask for one.

HOAs suck. I would hate live in a place subject to one. They always get cranky little Nazis running the thing.

Nearly sure NC has a law prohibiting that.

Your HOA may prohibit solar, but they can’t prohibit huge radio equipment that you’d put up if you can’t do solar. Just give them the choice – intentionally ugly radio tower, or solar panels you try to make look good.

New Jersey.

He actually moved to from New Jersey to North Carolina.

Pretty damn cool! I get that this is a off-grid thing and all but I was just wondering if it’s possible to sell energy back to the grid in the US?

Yes, in some states you can sell power back to the grid, but you usually buy at retail rates and sell back to them at wholesale (lower) rates. It helps offset some of the install costs.

Yes, with a grid tied system, you sell electricity to the electric company when you overproduce and buy it back when you need it. For Southern California, there are three time periods, Peak, Off-Peak and Super-Off Peak. Selling to the power company during Peak and using during Super-off Peak (like charging your car) works really well. I have two electric cars, a 3000 square foot house and a 5kW system. I settle with Southern California Edison once a year. For the second year in a row they sent me a check for $65. So no electric bill.

Who did you buy your panels from? I would love to do the same.

Yes, but it generally doesn’t make much financial sense since they’ll pay you rates that are really low unless there is some special rate due to RECs (renewable energy credits).

Where I live, they’ll pay you retail rate up to what you consume. After that it is like 4 cents/KWH. Some places are down at 2.x cents.

That’s a crazy amount of power! I guess he’s aiming at winning the neighborhood Christmas decoration competition this year 🙂

Also, why not use a combination of wind and solar? They would probably complement each other quite nicely and probably mean needing fewer batteries.

What to do with the excess power? Hmm maybe invent a residential pumped hydro storage device?

“excess power” occurs with any solar system. On a grid tied system, you watch your meter send the power to the outside grid, and what happens after that is not your concern. But in reality, if the grid load cannot accept the power, then it is effectively wasted. Having an “off grid” system (I add quotes here because that term is more typically used for a rural system and not city based), simply illustrates what happens in any system graphically. IE., you meter where all of the power goes, so you see the “waste”. Here, because you are making more power than the batteries can use, it is wasted. This is going to be true by definition. Wait what? Yes, think of the contrary. If you generate less than the batteries can hold (on a frequent basis), then you have undersized the solar array with respect to the battery array. Put another way, you won’t be able to bridge those times when the sun does not shine as much as the battery capacity you paid for will provide. With an off grid array, you are managing all of your own power, and there are trade offs. The right way is… Read more »

Wind doesn’t work for us here in NC

Hey Mark,
If you go thru the math, it looks like he’s only averaging 2.7 hours a day charging at rating plate power. Out here in AZ my system averages 5 hours per day so he must be somewhere where it’s cloudy alot.

The other thing that blows me away is he uses 120 kwh/day. whew boy that’s a lot of kwh.

anyway cool install!! I wonder if he made his own battery storage out of salvage Tesla packs.

2 Tesla’s. Relatively rural area so long driving.

120 is not a lot for heating, cooling and driving. Winter is tough. His house isn’t that new and heat pumps are not particularly high efficiency if I remember correctly.

I have a bigger house in the same climate with 2 EVs. I use a bit less but I use some NG. Newer house though. Solar hot water too.

A good way to go towards zero fossil:

1)Replace all fossils by electric counterparts. Heater by ground heat pump. Gas cooking by induction cooking. Gas car by ev. Etc…
2)Reduce use of all by increasing efficient. Passive housing or very high insulation. Shower waste water heat recuperator. Low energy lighting by using LED.
3)Increase electric auto production. PV on the roof. PV on car port. Wind generator.
4)Energy storage for night time.

He’s not using micro inverters!! must be a central inverter system which makes more sense if you are doing batteries

Small scale wind is really inefficient and generally doesn’t pay back. It works much better at large scale and that that’s why the wind turbines are getting MASSIVE.

But for a small off-grid cabin, it would be nice to have just for the fact that it can generate power at night and during storms when solar is pretty useless.

It is harder to get permits for wind too due to noise and danger of it tipping over. And as a mechanical device, it will eventually require maintenance.

“…why not use a combination of wind and solar?”

Because most home installed wind turbines only generate, even at best, 1-2% of a home owner’s needs; not to mention wind power is entirely unreliable, and not likely to deliver power when needed the most. In other words, a home wind turbine is nearly always more for show (or for making the owner feel good) than for anything practical.

In practical terms, wind power isn’t worth bothering with for most home owners. There are of course exceptions, in rare areas where wind really does blow more or less steadily nearly all the time.

On a house, additionally to standard wind generators, you can use the roof slope as a wind booster for an horizontal wind generator on the roof ridge.


There are some new possibilities in micro pump storage too like this adapted system:


98.4 % is pretty good. 99.9% may be possible!

Yeah, he needs to add a wind mill to his power grid. They complement the solar power in cloudy days.

“It is clearly not an economical option”

Why is that?

If we use my install as an example, I have a 10kWh installation and it cost about $42,000. Since his install is about 4.4 times larger, his install probably cost more than $180,000 if his costs were similar to mine. $180,000 will buy you ALOT of electricity from the grid.

Thats pretty expensive. My 5kW system cost me $6500 after the 30% tax credit. I didn’t use a contractor and bought the panels myself though.
This is a great place to see current panel prices:

Yep, this is the way to go if you are an electrician, an electrical engineer, or a talented DIYer. It is basically free money.

He installed it himself. If you install yourself, that knocks about half the cost of a PV system. The PV equipment is pretty cheap these days . . . but designing a system, getting permits approved, installing, getting it inspected, etc. costs a lot of money.

But seriously, anyone who owns a home and has DIY skills, they are CRAZY not to install their own system. It really is free money falling from the sky every day.

44.4 kW off-grid solar system . . . HOLY CRAP.

That is a massive system for a house. OK, he does live in New Jersey so he doesn’t have the sun I have. But I have a 6.1KW system and it generates more electricity than I use. Then again, I don’t drive much.

Well he needs it for charging two full electric cars.

The 44.4kW of solar panels is not even the crazy part. He has 191.25 kWh of Tesla battery modules connected to 8 Outback Radian inverters for a total of 64kW AC output to power his house.

If you really want the nitty gritty details, check out his old thread on TMC.

That is one crazy system. Where I live in California, I get great sun . . . I could power all the houses on my street with that system!

But I noticed that he really went all out . . . he said “my home is fully electric. Electric heating and cooling (air source heat pumps). Electric cooking. Electric vehicles. No natural gas, oil, etc.” I have natural gas for cooking, hot water, and heat. I would need a much bigger system if were to try to get rid of my gas heat and gas hot water. It would be do-able though, especially if I added hot-water solar and installed a heat-pump system.

But I would still keep my gas stove because I like cooking with gas.

Agreed. I have nat-gas hot water and central heat. I could get by with one 8kW inverter and 40kWh of battery and run my house for a week except EV charging. That would also allow me to shift all my grid draw to off-peak and self-consume most of my solar during the evenings.

I wonder if home developers will start considering providing “common” solar power installations in their developments, and market their homes with “free” (or massively lowered) electricity costs.

(I’m sure the power utilities will lobby for laws prohibiting such systems.)

This is a great idea and you can bet the utilities will pull out all the stops as soon as it’s suggested.

This is actually not that complicated. If you were building a large subdivision that was going to have a HOA, it could be structured so that the HOA owned all the electrical distribution within the subdivision and it could register itself as a small municipal utility. They could buy electricity as needed from the utility at higher distribution voltages. Solar and batteries could be deployed as needed to minimize what is paid to the master utility. In addition, it could use a mix of capitalized cost built into the initial purchase prices of the houses and monthly fees. However, it would all be a big hassle to set up within the regulatory framework of wherever it is located. Large builders could streamline the process by re-using the legal documents and engineering from one project to the next.

Thx for the link. It will take a while…75 pages long!!

There is also a lot of discussion in those 75 pages about energy efficiency improvements that he could apply to his house and what he could do with the surplus energy when he has it. Even heating the pool would not absorb all his surplus.

One other interesting detail is that he ducted his heat pump water heater so that it would absorb the heat from the electrical equipment room, boosting the efficiency of the water heater and cooling the equipment room. However, he still needed a mini-split HVAC to control the temp in that room in the summer.

I am really struggling to understand why he ever needs to draw from the grid, even 1% of the time. I get that he has multiple EVs to charge, and a big house, but still. That’s an insane amount of electricity to use.

Impressive project but it should be more than apparent why most people cannot afford the space or cost of a hundred panels.

They also don’t need them. That system is massive overkill. It is a hobby for him.

WOW…instead of spending TRILLIONS OF $$$$ on invading and bombing Iraq and Afghanistan…a trillion dollar solar panel install loan program for American homes and businesses would create jobs, wealth, and clean air.

Absolutely, but then the poor armament company would lay off by thousand.
Sad, but this is the way thing is working around.

Unless armament company makes some other stuff like rockets, space vehicles, Moon habitats, -Moon rovers, Mars habitat, Mars rovers, Mars tunneling machine, Venus cloud city, Venus mining tele operated rovers and diggers, Venus space vehicles, all paid on the new space invasion budget financed by a 50% portion of the behemoth military one.

Exactly . . . I wish everyone would buy plug-in cars so that the value of oil just crashed. That would cut off the money supply to a lot of shady characters like African dictators, Comrade Putin, Sheiks that quietly give money to Jihadists, etc.

Let’s not commit the fallacy of false dichotomy here. We could have both avoided those optional wars AND continued to rely on predominantly fossil fuels for energy.

You’re assuming that the wars in Iraq and Afghanistan were for oil. More likely, they were wars of empire (control) and as you pointed out, to sell more weapons. Oil is the excuse not the reason. The fact is we don’t need the oil from the Middle East. The US had the option to not engage in either of those disastrous, ruinous wars and to go about our energy policy and fight against terrorism in completely different and far more productive ways.

The wars in the Mideast involving Western powers, over the last century plus, are all a result of conflict over control of oil fields, period. That’s the only reason we’re even involved in the Mideast, aside from our commitment to Israel. Sure, some conflicts have spread to regions with little or no oil, such as Afghanistan and Syria. But it was the conflicts over oil that created the tribal warfare which has spread to other areas of the Mideast. If oil wasn’t there, we wouldn’t have any military bases in the Mideast outside of Israel. If we didn’t have any military bases there, then there wouldn’t be any motive for radical jihadists to aim their wrath at Westerners; it would be strictly Arab-on-Arab violence, or Arab vs. Israel. Don’t make the mistake of thinking that the excuses that people use for making war are the actual causes. Wars are always group struggles for resources… including land as one resource (which is the basis of the Arab-Israel conflict). When there aren’t enough resources to go around, people divide themselves up into “us” and “them” and then fight over those resources. The various reasons given for dividing people up into “us” and… Read more »

Shame they ruined such a nice piece of property next to the pool with a ground mount system.

Should have put in a solar perch instead and would have a nice shaded spot next to the pool. Just say’n.

Clearly Jason is more into engineering than aesthetics.

It is true that the panels could as be used as the top of a large solar patio next to the pool. All it takes is somewhat longer vertical poles. No real extra cost but an added value as a patio.

Here are a few examples:

(link 1, link 2, link 3)

SparkEV-Fiat500-Leased - M3 Reserved - Bolt- TBD

Land and costs of that system. Kudos for green and off grid — that’s nice!

ROI–wise, very different for most urban/metro applications. Rooftops is primary the max — Most states CANNOT prohibit rooftop PV.

With Netmetering, our ‘puny’ 3.8kw system was able to power our 2 EVs for 36,000 miles and home for $1200 at TrueUp—granted this is sunny San Diego with minimal AC needs and Gas cooking/heating which averaged about $40/month.

A 44KwH system would power our entire street effectively. Very nice!!!!

I wouldn’t call using 120 kWh per day as being green. My use was 110 kWh per month before SparkEV and 250 kWh now; if it’s too cold, climb on the exercise machine; if it’s too hot, go to the beach.

As a hobby project, it’s great. But being green is doing stuff with less.

Great to see details on a home solar installation that actually provides nearly all the electricity. Other than installations in wilderness cabins (not full sized homes) where a grid hookup isn’t available, that’s pretty rare.

But this also contains a useful caveat: Even someone who planned to use no electricity at all from the grid, is occasionally forced to do so. Those who claim that entirely disconnecting your home from the grid is a practical plan, are in most cases not being realistic.

Exactly. He spent a quarter million or so and still needs the grid at times. I think it’s great that he and others are going all out – they help show what’s possible. But they also show the limitations.

This also shows how much those with much smaller systems need (and should pay for) grid services.

Instead of batteries, I wonder how it’d work out with hydrogen and fuel cell stack. Not for vehicle use, but for in-situ home use.