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NanoCrazed

NanoCrazed

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After some bum luck and frustrations losing stuff during extended outages, feeling pretty good right now!

29 solar panels and 3 Tesla powerwalls...

Suppose to be enough to let me run off grid for about a week, factoring in my all my tanks and equipment! And assuming no input charge...

..if i run out of juice, then I likely have more urgent things to worry about than my tanks. Hah!
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Sweet!!!

Those power walls are nice. I have been tempted.
Especially since I think PG&E is really screwing me with the whole "True up" thing.

The problem: With recent non-discounted pricing, I am no longer sure it is cost effective over lead-acid.
That, and I my solar inverter is grid-tied only.
 
iani said:
Who did you use for the install?
Click to expand...
I used NRG Clean Energy... Despite my trial and tribulations with the initial installer they sent, decent outfit overall. The second install team was top notch.

The batteries were straight from Tesla. Solid experience and team...

@Oakland Evan
 
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rygh said:
Sweet!!!

Those power walls are nice. I have been tempted.
Especially since I think PG&E is really screwing me with the whole "True up" thing.

The problem: With recent non-discounted pricing, I am no longer sure it is cost effective over lead-acid.
That, and I my solar inverter is grid-tied only.
Click to expand...

If you go Tesla, you don't need a battery-ready inverter. I installed one though initially, as I didn't want to be tied to a single choice but wound up paying extra for the capability that I am not using now.

So, there are options... of course, you can always upgrade your inverter, too... :p
 
rygh said:
Sweet!!!

Those power walls are nice. I have been tempted.
Especially since I think PG&E is really screwing me with the whole "True up" thing.

The problem: With recent non-discounted pricing, I am no longer sure it is cost effective over lead-acid.
That, and I my solar inverter is grid-tied only.
Click to expand...

2019 is the latest year for credits... so there's still time.

On a per battery basis, the Tesla batteries are still cheaper than the next nearest option (LG) and higher capacity. The 13kW LG option isn't available in the US... so your limited to the 9.6kW LG option versus a 13kW Tesla Powerwall 2.0
 
13kWh powerwall x 3 = 39 kWh of power... so if your tanks, eleventy seventy of them, use 1000 watts of power (heaters, pumps, lights) and that's probably a very low estimate, you can go without power for about a day and a half. Or are the powerwalls simply tied to pumps? Maybe you don't have as many tanks as I think? Either way, your installer may have sold you some magic beans if they're promising a week without power. I mean ok, your panels add to that during the day, I'm guessing the powerwalls allow you to island yourself so you can still be grid connected and use your solar?
 
When I was approached last year about the power walls, they said that I would use Solar during the day and draw from the power wall at night until exhausted at which point I will switch to the grid. Then they will get recharged during the day with my Solar.
 
lol -- I never did the math... so thanks for that! I am sure it's somewhere in-between grid power and solar. My solar production average capacity is about 40 kWh / day so likely it's factored in there.

But yes, the system is set up for both grid and solar... and optimizing storage in between those.
 
Ah ok, didn't know the powerwalls allow you to still use solar during the day, guess I should have figured it had some magic that manages to isolate you from the rest of the grid to allow you to legally produce power if you're grid tied.
 
I was one of the first PW2 residential installs. They are great. I have 2 of them which is relatively under-sized for me, but it was the most I could get and still be eligible for the PGE rebate that almost paid for them.

There’s no way they will cover all of your home/tank usage for that long by themselves, clearly you need solar to regenerate the batteries during the day. At that point, there is no way to say how long you could go without grid power because it depends on the sun and how much solar panel capacity you have relative to usage. When it is sunny you could go indefinitely, when it’s winter or cloudy probably just a couple days at most.

If you have solar and power walls, PGE rules say that you can only charge them from solar, except in well-defined emergency-type situations (“Storm Watch”). Apparently they don’t want you charging up at night when electricity is cheap and discharging to the grid in the afternoon when it is expensive. They should allow this though, because it would help them cover these times of greater need, and reduce their reliance on expensive and polluting peaker-plants.

Regarding the invert question, that is not an issue because the extra hardware Tesla installs takes care of that.
 
The irony : The power-wall should actually be counter productive, both for the grid and economically for you.

The most expensive power is at peak during the day, when PGE turns all the extra generators on, to
handle all the air conditioners and so on. Which is exactly when your solar panels are at max.

Without powerwall, you would be sending excess solar back on the grid exactly when it is needed.
So you should get a better price, and it benefits the grid.
But with powerwall, you instead store that spare power to batteries, and only use power later at night, when
it is cheaper and more plentiful.
 
JVU said:
...
If you have solar and power walls, PGE rules say that you can only charge them from solar, except in well-defined emergency-type situations (“Storm Watch”). Apparently they don’t want you charging up at night when electricity is cheap and discharging to the grid in the afternoon when it is expensive. They should allow this though, because it would help them cover these times of greater need, and reduce their reliance on expensive and polluting peaker-plants.....
Click to expand...

Agree, they should actually be ENCOURAGING that.

But then, what helps profit, versus what helps the environment, are two entirely different things.
 
rygh said:
The irony : The power-wall should actually be counter productive, both for the grid and economically for you.

The most expensive power is at peak during the day, when PGE turns all the extra generators on, to
handle all the air conditioners and so on. Which is exactly when your solar panels are at max.

Without powerwall, you would be sending excess solar back on the grid exactly when it is needed.
So you should get a better price, and it benefits the grid.
But with powerwall, you instead store that spare power to batteries, and only use power later at night, when
it is cheaper and more plentiful.
Click to expand...
That’s not the full story of how it works in practice. For me, I leave 30-50% of the battery as backup just in case we lose power when the sun isn’t up.

So, my solar panels fully charge the batteries every day in the morning and early afternoon during intermediate rates, then by peak time they are full, and I’m back to selling electricity back to the grid.

Then during the late peak-time when the sun sets, I’m using battery power to keep from drawing from the grid, further helping PGE (and my wallet).

Then, by the time the cheap rates come at 11p, I’m back to grid power (by settings) for the house.
 
JVU said:
I was one of the first PW2 residential installs. They are great. I have 2 of them which is relatively under-sized for me, but it was the most I could get and still be eligible for the PGE rebate that almost paid for them.

There’s no way they will cover all of your home/tank usage for that long by themselves, clearly you need solar to regenerate the batteries during the day. At that point, there is no way to say how long you could go without grid power because it depends on the sun and how much solar panel capacity you have relative to usage. When it is sunny you could go indefinitely, when it’s winter or cloudy probably just a couple days at most.

If you have solar and power walls, PGE rules say that you can only charge them from solar, except in well-defined emergency-type situations (“Storm Watch”). Apparently they don’t want you charging up at night when electricity is cheap and discharging to the grid in the afternoon when it is expensive. They should allow this though, because it would help them cover these times of greater need, and reduce their reliance on expensive and polluting peaker-plants.

Regarding the invert question, that is not an issue because the extra hardware Tesla installs takes care of that.
Click to expand...

I didn't realized PGE had those rules... still learning all this energy biz stuff...
 
JVU said:
I was one of the first PW2 residential installs. They are great. I have 2 of them which is relatively under-sized for me, but it was the most I could get and still be eligible for the PGE rebate that almost paid for them.
Click to expand...


Please tell us more about how you got “almost free” power walls. I would love to know as I’m interested in getting a couple. Thanks!
 
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