Power Wall Pricing

[beowulf]

At the risk of derailing the thread - what sort of fan do you have? Our house has an effective fan, but it's in the hall right next to our bedroom and even with it on low (I have a dimmer-like switch which is appropriate for motor drives) it sounds like a hurricane. I'm definitely replacing it this spring, but wondering what to replace it with!

We have the noisy one as well - bought at a big box store. It is installed in our hallway ceiling. They make others - more expensive - baffle type and those are supposed to be quiet. Even though ours is noisy we find that we only need to run it for 10-15 minutes to push the stale hot air out of the house and out of the attic and bring in the cooler outside air. Also, I have heard of a system where the fan is in the peak wall of the attic with duct work to a vent in the ceiling. Supposed to be quiet but I am thinking that system would not push the hot air out of the attic - unless I am misunderstanding the set up.

 

[ponytug]

We have the noisy one as well - bought at a big box store. It is installed in our hallway ceiling. They make others - more expensive - baffle type and those are supposed to be quiet. Even though ours is noisy we find that we only need to run it for 10-15 minutes to push the stale hot air out of the house and out of the attic and bring in the cooler outside air. Also, I have heard of a system where the fan is in the peak wall of the attic with duct work to a vent in the ceiling. Supposed to be quiet but I am thinking that system would not push the hot air out of the attic - unless I am misunderstanding the set up.

Perhaps you are thinking of the "Quiet Cool" brand of attic fans that are suspended to lessen noise?



They work by removing the warm air from the living spaces and dump it into the attic, where you need a gable or eave vent. Using a suspended fan assembly and a flexible duct reduces the noise.

All the best,

Peter

 

[somber]

The thing about Power Wall pricing that I don't understand: For EVs, the battery pack price is dropping fast, approaching $100/kWh. Why are the Power Wall and Enphase packs more like $1000/kWh? Seems like for an EV, you'd have more expense trying to keep it light weight, but for fixed mount, weight isn't much of an issue.

 

[Carl_NH]

I ran our well on 4K generator. 500' deep, with pump at 450' 1.5 HP. I would love to have NG at the house, but they said i'd have to give them a deposit of 1,000,000 dollars to start the engineering.

We did the same with a 4500W generator on out 1.5HP well pump, but at 22 Amps starting it was pushing it hard - could only run fridge and oil boiler, and a few lights. We upgraded to a 7500W unit and it handles it much better.

I looked into the PW too, and Tesla confirmed it will not handle the load of the well pump, and we would need 2 PW minimum, so are staying with the generator for now or maybe a 12KW whole house generator in the future. But power outages are getting less frequent as a result of better tree/line trimming so in the last 8-10 years only had two outages more than a day, and usually only 3-4 hours.

 

[beowulf]

Perhaps you are thinking of the "Quiet Cool" brand of attic fans that are suspended to lessen noise?

Peter, that looks what was described to me as a better, and less noisy option. I did not understand that the fan was mounted that way so that hot attic air would also be evacuated. I was assuming the fan was in the attic gable wall and was a closed system between the house and the outside. I like this a lot and should lessen any noise substantially. I assume you would still have louvers on springs that would only open when the fan kicked on, but that noise would be minimal and only for a second or two on starting and stopping. I have a friend who has a tricky attic and house configuration that would not accommodate the kind of fan I have but this might work for him. I will pass it on. Thanks.

 

[ning]

The thing about Power Wall pricing that I don't understand: For EVs, the battery pack price is dropping fast, approaching $100/kWh. Why are the Power Wall and Enphase packs more like $1000/kWh? Seems like for an EV, you'd have more expense trying to keep it light weight, but for fixed mount, weight isn't much of an issue.

Battery packs for homes include the inverters to get to 120v (x2 legs), while the battery packs for cars don't have inverters at all (AFAIK). This probably has something to do with it, but I'm not sure how much.

Tesla Powerwalls are similarly cheaper than eg Enphase at least partially for the same reason - the Enphase battery is an A/C product complete with intelligent inverters, while the Tesla is "... compatible with solar inverters from [lots of manufacturers]".

 

[ning]

Perhaps you are thinking of the "Quiet Cool" brand of attic fans that are suspended to lessen noise?

My daughter installed one of these in her house and she says it's a lot quieter than ours, but they don't sleep right next to the wall vent (hers is mounted in a mostly finished attic which has some unfilled attic space to vent still). I'm contemplating getting one - or possibly two smaller ones and mounting one at the other end of the house to keep each one doing less for hopefully less noise (though a bit higher cost)

 

[ponytug]

The thing about Power Wall pricing that I don't understand: For EVs, the battery pack price is dropping fast, approaching $100/kWh. Why are the Power Wall and Enphase packs more like $1000/kWh? Seems like for an EV, you'd have more expense trying to keep it light weight, but for fixed mount, weight isn't much of an issue.

I think that the issues are scale and cookie cutter process versus not. There aren't as many home batteries being produced, and home battery packs are scaling up. There is also the issue that home batteries have to include inverters and chargers as well. There is also the efficiency of building something in a factory, over and over, and over again. When you stick a battery on a house there are lots of quirks and issues. Some are predictable, e.g. having a large enough main service panel bus bar, and some are quirks of the local "authority having jurisdiction", who wants extra switches, special stands, or impact protection, or specialty insurance. All add to cost. I have heard some horror stories that turned a two day job into eight months and counting due foibles of the AHJ and the local power company, and an inexperienced installer.

With time, I think that national standards will emerge, and home batteries will become more cookie cutter, and cheaper, but they are never going to get down to the cost of batteries in a vehicle. I think that too much about home installation aren't cookie cutter.

All the best,

Peter

 

[Grumpycat]

The thing about Power Wall pricing that I don't understand: For EVs, the battery pack price is dropping fast, approaching $100/kWh. Why are the Power Wall and Enphase packs more like $1000/kWh? Seems like for an EV, you'd have more expense trying to keep it light weight, but for fixed mount, weight isn't much of an issue.

I don’t think EV batteries are under $300/kWh yet. Used 75 kWh Tesla batteries ask $12,500 on eBay and are not in a useful configuration for anything but transplant into another under-warranty Tesla.

Used 4.5 kWh modules from Tesla batteries ask $900 which includes a BCM designed to work in series or parallel with other like modules.

A Tesla Powerwall has 13.5 kWh of useful capacity in a complete integrated package with 100% duty cycle AC inverter/charger/controller. $7000.

Claims of $100/kWh are coming from wishful thinkers and not from a quality supplier who is capable of putting real product in your hands.

 

[Grumpycat]

Battery packs for homes include the inverters to get to 120v (x2 legs), while the battery packs for cars don't have inverters at all (AFAIK). This probably has something to do with it, but I'm not sure how much.

Tesla Powerwalls are similarly cheaper than eg Enphase at least partially for the same reason - the Enphase battery is an A/C product complete with intelligent inverters, while the Tesla is "... compatible with solar inverters from [lots of manufacturers]".

That is wrong. The Tesla Powerwall is stand-alone with integrated charger and inverter. It needs to network to a Tesla Energy Gateway which is essentially a glorified electric meter with disconnect to tell the Powerwall when to do what. One Gateway will manage a good number of Powerwalls, monitoring the grid, the weather forecast, and solar production.