Tesla Powerwall

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garsh said:
The new Powerwall 2.0 batteries include a built-in inverter for connecting to the mains. Along with the software for controlling it, this will automatically choose when to charge and discharge the battery. There will be no user-accessible "switch", other than a breaker (which is not something that a user should be flipping regularly).

Agree on automatic operation, but I can't believe there won't be a user-controlled timer you can set so that the charging of the pack only occurs at night at super-off peak rates, it sort of kills the whole time-shifting idea.
 
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LTLFTcomposite said:
So with powerwall 2.0 it sounds like a much more integrated solution. Just add panels?

As for backup, wouldn't that require an isolation/transfer switch? I guess since the powerwall would always be connected to the home's internal wiring (service panel) it wouldn't be a transfer switch per se, but there does need to be a disconnect to the utility, no?

Grid-tied solar inverters automatically stop sending power out when they sense power outage on the grid side. I suspect Powerwall will work similarly in a grid-tie configuration. There is also usually a manual disconnect as an extra measure. After all utility companies don't run to every home with solar to flip the switch when they need to work on a broken line or something.
 
Valdemar said:
Agree on automatic operation, but I can't believe there won't be a user-controlled timer you can set so that the charging of the pack only occurs at night at super-off peak rates, it sort of kills the whole time-shifting idea.
Yes, that will be user-controlled via software. I thought you were asking about a physical switch for this purpose.
 
So a grid tied system like powerwall stops producing if utility power is cut. For it to provide backup power it seems one of two things must be included in the installation:

-Whole house disconnect - this is expensive, 200 amp + contactor wired into the mains

-Moving selected loads to a subpanel so a lower amperage contactor can be used

That's similar to how home standby generators are installed here.
 
LTLFTcomposite said:
Moving selected loads to a subpanel so a lower amperage contactor can be used

I'm pretty sure this is the option Tesla will use:
1. Elon specifically mentioned that just a refrigerator, a TV, a few lights, and a couple outlets would be backed up, not the whole house.
2. This is the way most solar inverters are configured, like my Outback unit. You simply move all the above mentioned devices to a subpanel, install a larger breaker in the main panel to feed the Powerwall 2, probably a 40 amp, and then the output of the Powerwall 2 will feed the subpanel.
I haven't heard any mention of a transfer switch, or the ability to feed power back to the grid, but I sure hope so. My Outback has both, but details from Tesla have been very scanty, to say the least. I'm not in any real big hurry, now that I heard they have extended the Federal 30% tax credit for 3 more years.
 
smkettner said:
I am more inclined to go fully off-grid if I was to go power wall. Is this just a backup battery or designed for daily cycling?

Unless you have some philosophical reasons why you might want to do it going off-grid is pretty much guaranteed to be more expensive than grid-tied solar in CA because CA is a NEM state. For this same reason Powerwall doesn't make much sense in CA, except maybe for off-grid where it is really necessary (think cabin in the woods). I suspect Powerwall would mostly be used for time-shifting on TOU in CA in the observable future, you charge at night at super-off-peak rates and then avoid buying expensive energy during the day by using battery energy.
 
Valdemar said:
smkettner said:
I am more inclined to go fully off-grid if I was to go power wall. Is this just a backup battery or designed for daily cycling?

Unless you have some philosophical reasons why you might want to do it going off-grid is pretty much guaranteed to be more expensive than grid-tied solar in CA because CA is a NEM state. For this same reason Powerwall doesn't make much sense in CA, except maybe for off-grid where it is really necessary (think cabin in the woods). I suspect Powerwall would mostly be used for time-shifting on TOU in CA in the observable future, you charge at night at super-off-peak rates and then avoid buying expensive energy during the day by using battery energy.

=1
Although in my situation, in MN it makes perfect sense.
We already have solar, but have no backup heating/power source.
So with the Powerwall, even if there is a power outage we can heat our house in the winter.
Granted, it will be cooler than normal, but as long as it stays warm enough to keep the pipes from freezing I am happy:)
 
Zythryn said:
Valdemar said:
smkettner said:
I am more inclined to go fully off-grid if I was to go power wall. Is this just a backup battery or designed for daily cycling?

Unless you have some philosophical reasons why you might want to do it going off-grid is pretty much guaranteed to be more expensive than grid-tied solar in CA because CA is a NEM state. For this same reason Powerwall doesn't make much sense in CA, except maybe for off-grid where it is really necessary (think cabin in the woods). I suspect Powerwall would mostly be used for time-shifting on TOU in CA in the observable future, you charge at night at super-off-peak rates and then avoid buying expensive energy during the day by using battery energy.

=1
Although in my situation, in MN it makes perfect sense.
We already have solar, but have no backup heating/power source.
So with the Powerwall, even if there is a power outage we can heat our house in the winter.
Granted, it will be cooler than normal, but as long as it stays warm enough to keep the pipes from freezing I am happy:)


The worst thing to run on Powerwall is heating system.
Any heat should be stored in water tanks. You want to run water pump on Powerwall,
not heating elements. OK maybe heat pump, but it is very rare in US I believe.
 
arnis said:
Zythryn said:
+1
Although in my situation, in MN it makes perfect sense.
We already have solar, but have no backup heating/power source.
So with the Powerwall, even if there is a power outage we can heat our house in the winter.
Granted, it will be cooler than normal, but as long as it stays warm enough to keep the pipes from freezing I am happy:)


The worst thing to run on Powerwall is heating system.
Any heat should be stored in water tanks. You want to run water pump on Powerwall,
not heating elements. OK maybe heat pump, but it is very rare in US I believe.

Well, my heating system is a geothermal pump ;)
It is quite efficient, we have been designing this with efficiency in mind, both for its own sake and for backup power purposes.
 
arnis said:
The worst thing to run on Powerwall is heating system.
+1
arnis said:
OK maybe heat pump, but it is very rare in US I believe.
Not rare in the US, but certainly rare in MN. But even a heat pump uses a LOT of electricity. The big issue with the heat pump that we have here in VA is that we often do not need heat when the sun is out, only when it is dark.
Zythryn said:
Well, my heating system is a geothermal pump ;)
It is quite efficient, we have been designing this with efficiency in mind, both for its own sake and for backup power purposes.
That can be workable, but it still uses a massive amount of electricity. The smallest ones still consume over 5 kW but since you live in MN, it is likely higher. On cold days, you probably need to run that load about 24 hours per day.
 
RegGuheert said:
arnis said:
The worst thing to run on Powerwall is heating system.
+1
arnis said:
OK maybe heat pump, but it is very rare in US I believe.
Not rare in the US, but certainly rare in MN. But even a heat pump uses a LOT of electricity. The big issue with the heat pump that we have here in VA is that we often do not need heat when the sun is out, only when it is dark.
Zythryn said:
Well, my heating system is a geothermal pump ;)
It is quite efficient, we have been designing this with efficiency in mind, both for its own sake and for backup power purposes.
That can be workable, but it still uses a massive amount of electricity. The smallest ones still consume over 5 kW but since you live in MN, it is likely higher. On cold days, you probably need to run that load about 24 hours per day.

I'll let you know after we get into the colder season. :cool:
 
Geothermal heat pumps are not uncommon up here. We have a 4 ton heat pump with a 6 ton horizontal field which they over-sized becasue they thought we might need a 6 ton, which we don't. If our current heat pump ever goes out, I am getting a variable unit (or at least 2 stage), I would love to be able to use the 3kw of solar we have to run it, we can now, but running it pulls 4.5 kw and our inverter (XW6048) can only start it if nothing else is on, but most of the time we are grid tied so the grid picks up the starting surge. We do have natural gas as backup instead of resistance heat, and I watch the cost of natural gas vs off peak electricity taking in to account the COP (varies depending on field temp) and run which ever is less expensive, which right now is natural gas, but had primarily been geothermal in the past.

So for us when the power is out we use the natural gas instead of geothermal.

Back on topic, I like the compact size of the Powerwall 2 and the simplicity of it compared to our system. However I can power our house from, solar PV, the grid, one of two backup gensets, an idling vehicle or the Leaf :)
 
Geothermal stuff is awesome. BUT. What the heck.
Expensive machine is on/off type ?? :eek: :(

Whenever possible I would recommend inverter type heat pumps.
Like Nissan Leaf has - infinitely variable speed 100W to at least 2250W
(anybody knows the AC compressor electric motor power Leaf has?)


4.5kW input power makes at least 12kW of heat. Holy cow.
This pump should be off most of the time for average house :|
I live in a small-medium sized house (100m2), and at -15*C it needs 4kW of heat.
My inverter type split air-air heat pump can produce 3.5kW of heat with
1kW of electricity. And can handle the whole house down to -5*C.
Let's talk about insulation :lol: (nooot, way to awesome topic)


Inverter type heat pumps will level out once temperature has been reached.
For example 1500W of constant draw at xx outside temperature (and no hot water
used). It is possible to stop drawing power during peak electricity prices but that
needs large enough water buffer to keep house warm during that period.

This constantly slowly running compressor should last at least two decades
due to almost no cold starts. Also more efficient compared to on/off.

Interesting. Is Powerwall capable running in parallel with small gas generator.
 
BrockWI said:
However I can power our house from, solar PV, the grid, one of two backup gensets, an idling vehicle or the Leaf :)
To me, this is the key thing to have in place. I have a similar array of options for our home:

Heat:
- Air-source heat pump: Strictly grid-tied. I do not even have this set up to run from the generator.
- Wood pellet stove: We used to heat the entire house for the winter with this unit, but the price of pellets has doubled and we now have net-metered photovoltaic electricity that cover our heat pump's consumption. The fans and auger only consume about 120W of electricity when operating.

Cooking:
- Everything is electric except we have a propane cooktop (and a propane oven which draws about 300W for its igniter).

Water:
- We have a well pumped by a 1/2 HP submersible. The pump is 240VAC, but I added an autotransformer after the pressure switch to allow it to be run from 120VAC if needed. It has a high starting surge, but only draws about 1000VA when operating.

Hot Water:
- We have a heat-pump water heater that only draws 600W when running. It is also 240VAC, but I do not have it set up to run from 120VAC through an autotransformer since we sometimes (but rarely) use the 4.5kW resistive heaters. I have a couple of autotransformers kicking around here, so I certainly could wire it for 120V if needed.

Dryer:
- We have BOTH a propane dryer AND an electric dryer. We used to use propane when the house was off-grid, but I switched it for an electric unit when we decided to move to a grid-tied arrangement. The propane unit could be switched in if needed for emergencies (or we could simply hang the clothes to dry).

Electricity:
- Our house is powered by grid electricity with just over 100% of our consumption offset by net-metered, grid-tied PV.
- We have a 6500VA Honda generator which is connected to run everything except our heat pump and our electric double oven. It can simultaneously run the wood pellet stove, the well pump, the water heater and charge the LEAF.
- We have 800Ah (nameplate) of 12V AGM batteries. I got them for free because they were badly sulfated down to only 200Ah of capacity. My little BatteryMinder 1500 is dutifully pounding away on them to try to recover their capacity. Last time I tested them, they were up to 300Ah! Since there's no hurry, I just let that thing continue to do its work of recovering capacity.
- To go with the 12V batteries, we have a 2000VA Outback inverter that puts out 120VAC. This should be able to run any of the loads which the generator is connected to, although I have not tested it with the surges of the well pump or water heater yet. The most important load for these batteries is the pellet stove, which it should be able to run for a day with the current capacity of the batteries or three days if they ever get fully desulfated.
- In a pinch, I could rewire one or more PV panels to charge the 12V batteries.
- Then there is the LEAF. I have a couple of 120VAC inverters which work with it. Since there is a fridge and deep freeze in the garage, those are its primary loads, but I have used it to run the pellet stove in the past, since it is easy to set up.

Overall, we are set up to provide the essentials and more in case of an emergency.
 
I just got an invitation to a "Tesla Social" down in Boca Raton on Sunday. I've never gone to one before, but this time: " This month we are giving you an inside look into our newly launched Powerwall 2, Tesla’s next generation home battery solution."

So, hopefully I will get more detailed info on what the Powerwall can and can't do, as so far there have been few, if any, details. I was planning on adding some solar to the guest house that I built here for my parents, and if the Powerwall 2 can do everything an SMA inverter can do, plus add battery backup, I'm going for it. :D
 
keydiver said:
So, hopefully I will get more detailed info on what the Powerwall can and can't do, as so far there have been few, if any, details.
Thanks! If any of the covers are off, could you please snap pictures of what is hidden behind them? TIA!
 
Correct me if I am wrong, but it sounds like the box is a grid tie inverter, downstream UPS with batteries and a solar charge controller with a solar input.

So grid in, solar in and backup / solar out. Can it back feed the grid or is it only downstream?
 
BrockWI said:
Correct me if I am wrong, but it sounds like the box is a grid tie inverter, downstream UPS with batteries and a solar charge controller with a solar input.

So grid in, solar in and backup / solar out. Can it back feed the grid or is it only downstream?
From Tesla's website:
Tesla said:
Supported Applications
- Solar self-consumption
- Time of use load shifting
- Backup
- Off grid
Given this, the inverter should be both grid-tied AND autonomous. I seriously doubt that it would contain a solar charge controller and I doubt that it contains a transfer switch since that would seem to be a function which would not be required in every unit if they were paralleled.
 
Tesla Solar/Energy Storage Headed To 800 Home Depot Stores, Maybe Lowes, Too
InsideEVs said:
During the first half of this year, some 800 Home Depot locations will receive Tesla solar displays with Tesla employees on hand to talk about what’s on offer.
InsideEVs said:
The costs of Tesla products (average/typical):

Solar panels $10,000-$25,000
Powerwall: $7,000
Solar Roof: $52,000
Crossposting in the Tesla responsible for slide in U.S. home solar sales thread
 
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