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Discussion Starter #1
Hey guys,

Anyone here also into home energy? What are the good dc/ac inverter options out? EVTV has some for sale but they are $15k! Its hard to believe there arent cheaper and better options out yet.

I have a Tesla pack and I am looking to install an inverter so it can power my home.
 

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grid tied or not? non-grid tie is more diy friendly, just an inverter (some igbt and inductors and control logic). but grid tie you might be able to offset your existing bill.

Even if I was off grid solar, I'd still have some sort of generator handy, could even be the motor/generator out of an old prius or something that already makes enough bus voltage for the inverter.

edit, don't forget about mppt and battery management.
 

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Discussion Starter #3
grid tied or not? non-grid tie is more diy friendly, just an inverter (some igbt and inductors and control logic). but grid tie you might be able to offset your existing bill.

Even if I was off grid solar, I'd still have some sort of generator handy, could even be the motor/generator out of an old prius or something that already makes enough bus voltage for the inverter.

edit, don't forget about mppt and battery management.
Hello Steve, thanks for your post. I am currently grid tied. From what I have heard, it is illegal to disengage from the grid in my area. I am not sure if its a nationwide thing or just shitty NY. I want to install a switch to go back and forth myself.
 

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Hey guys,

Anyone here also into home energy? What are the good dc/ac inverter options out? EVTV has some for sale but they are $15k! Its hard to believe there arent cheaper and better options out yet.

I have a Tesla pack and I am looking to install an inverter so it can power my home.
OH hell no. Steer clear of his stuff unless you happen to be a multimillionaire and can just willy nilly go buy shit for what ever someone wants.
 

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Hello Steve, thanks for your post. I am currently grid tied. From what I have heard, it is illegal to disengage from the grid in my area. I am not sure if its a nationwide thing or just shitty NY. I want to install a switch to go back and forth myself.
If its illegal then fight to make it legal. In the mean time you can have one thing connected to show you use the power and then disconnect everything else. You end up paying a minimum bill to cover paper costs but it keeps you legal. Nothing illegal about having an OFF GRID system that does not connect to the GRID.
 

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Discussion Starter #6
If its illegal then fight to make it legal. In the mean time you can have one thing connected to show you use the power and then disconnect everything else. You end up paying a minimum bill to cover paper costs but it keeps you legal. Nothing illegal about having an OFF GRID system that does not connect to the GRID.
True, can you recommend an inverter that is designed for a whole house? I would have to check my breaker box but my guess is that I have at least 200 amp service. I live in the US so it is 240 volts.

My battery pack is made by Tesla with a peak voltage of 386 volts. The fuse on it is 350 amps.
 

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In the mean time you can have one thing connected to show you use the power and then disconnect everything else. You end up paying a minimum bill to cover paper costs but it keeps you legal.
If you are going to have all of the overhead costs of having a connection, why not use it? Sell excess energy to the grid, and keep the ability to buy as much as you need for anything you have in case you need it. This is a hybrid system... and to be fair it is the most expensive (due to complexity) of the choices (which are off-grid with battery, grid-tied without battery, grid-tied with backup, and hybrid).

Also, since the only reason for a requirement for power grid connection is to ensure habitability of the residence, a grid connection to some token device may fool power company administrators, but wouldn't pass any inspection.
 

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Hi Jim
You need to do some planning
I have a 5Kw inverter for my solar system - I think they are now about $1500
http://www.goodwe.com/
I have one of these - seems to be a very nice solid object with lots of features that I'm not using

What do you want to do?
Where is the power coming from?
What eats the power?

An average New Zealand home eats about 20 kWh per day - so on average less than 1 Kw continuous

200 amp at 240v is about 48 KW - I would be very surprised if you could draw that much!

Plan it out - do a daily plan thinking about what is switched on and when - and if they need to be on at the same time

Then see how much you need
 

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200 amp at 240v is about 48 KW - I would be very surprised if you could draw that much!
Decades ago, much lower capacity service was normal; my first house was built in 1954 and I think it had 60 amp @ 240 volt service. That was not enough for everything that a typical family would have, and by the 1970's 100 amp service was normal in Canada. Since then it has escalated, and 200 amp service is typical, at least for electrically heated houses. One problem might be that the total of the all of the circuit breaker capacities in the panel must not be more than some defined multiple of the panel and service capacity, to minimize the chance of overloading the service. Since there is much more branch circuit capacity than would ever be used at once - largely to provide outlets where ever they might be needed - the numbers are large.

I agree that the residence is unlikely to ever use 200 A @ 240 V even momentarily, but some components will need to be sized for that.

Actual peak draw is an interesting question. Typical North American homes have an electric kitchen range with multiple stovetop elements plus the oven, with 50 A @ 240 V service. The clothes dryer is typically electric: 30 A @ 240 V service. Kitchens have multiple 20 A or even more 15 A circuits, to handle appliances such as toasters, kettles, and other cooking appliances. Air conditioning is common - no idea offhand what that takes, but it's significant. While modern LED lighting is no big deal, the incandescents of a few years ago can easily be a kilowatt over the whole house, and peaks can be much higher with stuff such as outside floodlights. The piles of electronics are small change compared to heat-producing appliances. The really variable part is what is plugged into outlets - maybe next to nothing, maybe multiple 1500 watt portable heaters, large woodworking power tools, and a 5 horsepower air compressor in the garage. While most people here use natural gas for both space heating and water heating if gas is available, millions of people in Canada have electric heat and even more have electric water heaters; space heating alone is over 20 kW for a typical house, and whole-house water heaters run about 6 to 9 kW. With unfortunate timing, a 20 kW peak in a home even without electric heating wouldn't be implausible.

Of course a solar user going off-grid likely won't use plain resistance electric heat (more likely would use a heat pump or another energy source), and would likely be reasonable with other loads.
 

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Discussion Starter #10
Here is my energy usage.

https://photos.app.goo.gl/G537nac4zDHbA5zr1

I dont have solar panels yet but I plan on adding them soon. When I do I want to add an electric hot water heater and range. Currently both are propane.

An auto switcher that goes back to the grid once my battery is used up is fine too. As to the comment about selling back to the grid, Id rather use it myself from my battery than sell it back to the grid. Follow me here, if I make the power and sell it to the grid they give us pennies, something like $.06 per kw. Then when I need it, they sell it to me for $.12 per kw. Why bother with that? I like Jack Rickard's idea of "selfish solar".
 

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...

My battery pack is made by Tesla with a peak voltage of 386 volts. The fuse on it is 350 amps.
Is that an external fuse that you added, or is that internal to the pack?

It seems like most of the internal Tesla fuses that we have seen posted have been rated ~650 Amps and the datasheet shows I2T ratings could handle 1500 Amps for ~20 seconds.

Has anyone ever read or heard of a tesla main pack fuse blowing during operation--i had never seen that reported over a couple of years while following the tesla club forum.

i'm interested in the home solar/inverter technologies also and in what you find will work.
 

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Hi Jim
That was your monthly usage

You need to get down and dirty and into your usage by the hour to see what you actually need!

On a monthly basis you used a maximum of just over 2 Kw continuous - but that does NOT tell you what you need

Get a piece of paper or a spreadsheet and walk around your house looking at what's on and writing down the usage at that time

Lay it out and think about it

Maybe you can lock certain high power usage items out - and only use them at certain times so they don't get used at the same time as some of the other high power devices

Charging the car
Electric cloths dryer
Electric Hobb
Electric heating

If you want to use an inverter with it's limited output you need to understand what you are doing

OR you can use a grid tie system like the one I have where the solar inverter just feeds the system and the grid is there to cope with any large power calls
 

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Discussion Starter #13
Is that an external fuse that you added, or is that internal to the pack?

It seems like most of the internal Tesla fuses that we have seen posted have been rated ~650 Amps and the datasheet shows I2T ratings could handle 1500 Amps for ~20 seconds.

Has anyone ever read or heard of a tesla main pack fuse blowing during operation--i had never seen that reported over a couple of years while following the tesla club forum.

i'm interested in the home solar/inverter technologies also and in what you find will work.
It is the internal fuse. Rav4 EVs were detuned because its only front wheel drive. Its already a lot of power for the car as it is.

Yes I have heard of one Rav EV losing power on the highway due to a blown fuse.
 

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Discussion Starter #14
Hi Jim
That was your monthly usage

You need to get down and dirty and into your usage by the hour to see what you actually need!

On a monthly basis you used a maximum of just over 2 Kw continuous - but that does NOT tell you what you need

Get a piece of paper or a spreadsheet and walk around your house looking at what's on and writing down the usage at that time

Lay it out and think about it

Maybe you can lock certain high power usage items out - and only use them at certain times so they don't get used at the same time as some of the other high power devices

Charging the car
Electric cloths dryer
Electric Hobb
Electric heating

If you want to use an inverter with it's limited output you need to understand what you are doing

OR you can use a grid tie system like the one I have where the solar inverter just feeds the system and the grid is there to cope with any large power calls
Yes I do need to dig into it more. I dont have $15k for an inverter right now so it isnt a pressing task. I am interested to hear what you guys are using and how much you have spent. If it would only cost me a few thousand I might dive into it more.
 

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My inverter was about $2000 - 5Kw
But I have seen them for about $1500 - and that's NZD so about $1100 USD
So I would say that $15,000 is about a factor of 10 too high!
 

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Discussion Starter #16
My inverter was about $2000 - 5Kw
But I have seen them for about $1500 - and that's NZD so about $1100 USD
So I would say that $15,000 is about a factor of 10 too high!
How do I know how large of an inverter I need? Add up everything that could possibly be on at the same time? Seems like that would make it artificially large.
 

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That why you need to sit down and do your "plan"

You will need the input power - solar?
The battery
The Grid

You need to "Game it" - try lots of possibilities on paper - or spreadsheets!

I'm using a simple system - the solar panels feed the inverter and it makes AC - which it delivers to my house
I'm also connected to the grid
Basically I use power as I want - if I'm using more than Solar then it comes from the grid
Less then the surplus goes to the grid (and they only pay a pittance)
This is all automatic

The next stage would be a battery - a charger and an inverter - so that instead of dumping to the grid it would charge the battery - and instead of drawing from the grid it would draw from the battery
I could also take advantage of different night/day power charges

At this stage you need something with a bit more smarts - and you will need to tell it what to do

Get your paper and try some options - it's a lot cheaper than buying anything - and until you know what you CAN do
 

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I'm using a simple system - the solar panels feed the inverter and it makes AC - which it delivers to my house
I'm also connected to the grid
Basically I use power as I want - if I'm using more than Solar then it comes from the grid
Less then the surplus goes to the grid (and they only pay a pittance)
This is all automatic
Classic grid-tied system. This is optimal if
  • power during grid outages is not needed or important, and
  • the utility buys excess energy at or near the price of energy purchased from the grid.
This covers a lot of solar installations, but of course not everyone, depending on local factors. Here in Alberta utilities pay enough for "microgenerators" output and in most areas power delivery is reliable enough that a basic grid-tied system is a good choice.

Even this system without storage is not trivial to build correctly. A safety risk in this sort of system is that if not controlled properly it can create an electrocution hazard if the grid connection fails near but outside of the property.

Of course if using on-site storage (for any reason), this basic grid-tied system is not applicable.
 
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