No 800v for Model 3/Y, but maybe for Cybertruck?

[ajdelange]

My comment was based on my recent experience with building a charging carport i.e. a shelter in which I could park and charge my BEV from the sun without any grid connection. It transmogrified into what the contractor starting referring to as my "garagemahal". It has 45 panels (13 kW) and 5 Powewalls (i.e. 5 hours full sun equivalent) backed up by a 20 kW generator. It's proving itself out as we move into the heavy A/C season and it's really nice but I am afraid to sit down and figure the total cost.

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[Deleted member 12457]

I currently have one residential rental unit. My plan is to do a big Reno when I can afford it and add two more. At that point I also want to go fully solar, and have every unit with its own private garage with ev charging. It will cost a bit extra, but I think it’s worth it to get better tenants. I also think it’s the right thing to do, and keeps you future proof as gas get phased out.

"Better tenants"? Does that mean tenants with more money? Why should richer people be the only ones who have things that others can only dream of? I assume all of us want to get rid of ICE vehicles--ok most of us. What's going to happen when our regressive 25% EV vehicle import duty is repealed and well made, reasonable priced Chinese built EVs finally reach the US? Shouldn't landlords design EV upgrades into their housing? Anacortes has been infiltrated by way too many retirees from Seattle and other states, paying cash for houses that has driven up housing by 50% in the last 3 years. My landlord grew up in Anacortes, knows all the old timers and is trying to provide good housing for people instead of simply getting rich. This is what Anacortes used to be. I am a great tenant but my life isn't what it used to be and I was extremely lucky to find a one bedroom house to rent that isn't costing me $3K/mo.

Sorry for picking on you but everyone deserves a good, safe place to live with features others have to help reduce carbon emissions allowing this world to survive. Solar and EV charging facilities don't have to be only for the rich. All of you who have installed solar and EV chargers should have run the numbers and found where the cost break even point is.

 

[Crissa]

Tenants looking for specific features tend to treat the place better.

Sometimes that's more wealthy, sometimes it's not.

-Crissa

 

[ajdelange]

Why should richer people be the only ones who have things that others can only dream of?

Because they are the ones with the money! (nod to Willy Sutton).

 

[TheLastStarfighter]

"Better tenants"? Does that mean tenants with more money? Why should richer people be the only ones who have things that others can only dream of? I assume all of us want to get rid of ICE vehicles--ok most of us. What's going to happen when our regressive 25% EV vehicle import duty is repealed and well made, reasonable priced Chinese built EVs finally reach the US? Shouldn't landlords design EV upgrades into their housing? Anacortes has been infiltrated by way too many retirees from Seattle and other states, paying cash for houses that has driven up housing by 50% in the last 3 years. My landlord grew up in Anacortes, knows all the old timers and is trying to provide good housing for people instead of simply getting rich. This is what Anacortes used to be. I am a great tenant but my life isn't what it used to be and I was extremely lucky to find a one bedroom house to rent that isn't costing me $3K/mo.

Sorry for picking on you but everyone deserves a good, safe place to live with features others have to help reduce carbon emissions allowing this world to survive. Solar and EV charging facilities don't have to be only for the rich. All of you who have installed solar and EV chargers should have run the numbers and found where the cost break even point is.

Seeing as you're on forum discussing a premium/luxury vehicle that 98% of the global population can't afford, I would suggest you already know the answer to your question. And unless your intent is to purchase your shiny new truck and then give it to the first homeless person you see, you can get off your moral soapbox.

As far as better tenants = richer, no, that's not the case, not entirely. My rental units aren't for the wealthy. But they are for people with a job, who aren't on drugs and who take pride in where they live. I've rented to a group of young guys fresh out of highschool and they wrecked the place, broke the fridge and left garbage to clean up. I rented to a single mom on social assistance - she was great until she got a new boyfriend, made a mess of the place, filled the basement with garbage and left without notice. Both experiences cost me more than I brought in from the rental unit. If you believe all people deserve the same level of housing, equally, do you want to cover the losses for me?

Since I purchased my current property I've rented to young working professionals and never had an issue. I put a lot of money and effort making the apartment the kind of place I'd like to live, and as such any time it comes up for rent there are multiple applicants within hours. That helps me to find someone who can pay the rent on time and will treat the place with respect.

Moving forward, it's my observation that people that care about the planet will likely care about things in general. People that don't care about he planet are less likely to have a problem with trashing their apartment. Call me crazy. I live on the property too, so they're my neighbors as well. And I like having neighbors that are sensible, professional and eco-conscious.

 

[TheLastStarfighter]

My comment was based on my recent experience with building a charging carport i.e. a shelter in which I could park and charge my BEV from the sun without any grid connection. It transmogrified into what the contractor starting referring to as my "garagemahal". It has 45 panels (13 kW) and 5 Powewalls (i.e. 5 hours full sun equivalent) backed up by a 20 kW generator. It's proving itself out as we move into the heavy A/C season and it's really nice but I am afraid to sit down and figure the total cost.

lol, love the name Garagemahal. I would have a sign made up with that.

I went on a bit of a ramble with my response, but I guess I was mostly just saying that a lot of the costs in building car-charging garages for rental units would happen anyway, or offset other costs, like snow clearing. My electric bills are huge, so solar is absolutely justified. If Solar roof comes here, again, even better, since I'll be building roofs anyway.

Was your system expensive? I've done several PV installs, the biggest was for a large hockey rink and was about $230k. A smaller one was around $75k. I expect my building draw would be somewhere in the middle, around $150k based on the prices for those installs. Keep in mind I'm in Canada, and those quotes were for Government, which is always inflated a bit. I believe the rink was a 100kW system. If I could get the system done for $100k, I'd be pumped. Expensive, but since I pay $20k a year in electricity, they payback is super quick. Adding EV charges for each unit would be relatively cheap but add a premium feature.

I do have a question on powerwalls. Do you really need 5? I was thinking 6 would pretty much do the job of what I'd be looking for, but maybe I'm way off. And were they expensive? The cost may be hard to justify with netmetering available.

 

[Crissa]

Actually, yeah, I do think we should support updating or maintaining rental stock, putting people in control over their living arrangements without needing a huge up front investment.

But, well, that's just because I can observe that the market doesn't produce the amount of housing and types of housing needed.

-Crissa

 

[ajdelange]

Was your system expensive?

Yes, it was. As I said in an earlier post I'm afraid to look at the actual bill but the average cost for PV in Virginial is 2.88/W and I've got a 13 kW system so that would be 37K USD before incentives. Powerwalls are $8,500 USD so 5 of them comes to $42K before installation and incentives so we've got close to $80K total.

I've done several PV installs, ...

I really don't see how you could compare my project to anything a sane person would undertake. The main requirement was to house, with a/c and heating, 3 BEV and charge them without connection to the grid.

I do have a question on powerwalls. Do you really need 5?

I don't really need any as my utility provides net metering. But as you said in an earlier post the utility is fighting tooth and nail (and losing at the moment) to get rid of it or neutralize it with extra fees. In this experiment I wanted to be completely grid independent. With functioning net metering I really don't see the powerwalls, expensive as they are, as being justified unless your tariff is such that load leveling or load shifting is beneficial. If you do want them the minimum order is 2.

I was thinking 6 would pretty much do the job of what I'd be looking for, but maybe I'm way off.

Maybe but maybe you are sufficiently close to being right. There really is no right answer. It is very much based on the statistics of the sun/weather, your utilization, how often you are willing to sit in the dark, what means you have for load shedding etc., etc., etc.

And were they expensive?

Yes!

The cost may be hard to justify with netmetering available.

If the utility is reliable, it its tariff is level (no TOD features) and if net metering is available I do not think Powerwalls can be justified.

 

[TheLastStarfighter]

Actually, yeah, I do think we should support updating or maintaining rental stock, putting people in control over their living arrangements without needing a huge up front investment.

But, well, that's just because I can observe that the market doesn't produce the amount of housing and types of housing needed.

-Crissa

"We" should, sure. But not I. Everyone should have access to safe, affordable housing. But we also can't ignore that there are challenges with providing it. Locally, there's a housing crisis in Halifax and quite a few homeless. The city opened up a facility to house them instead of camping in city parks. Most of the homeless didn't want to go there, because they didn't like the other homeless. Violence, crime, etc. No private property owner should be forced to provide shelter to people who will then destroy their property.

Personally, I think the government should make significant investment in public housing that also provides counseling, drug treatment, education and extensive policing for a safe environment for the homeless... not only for shelter, but to address the issues that got them there. But that's another story.

 

[Crissa]

No private property owner should be forced to provide shelter to people who will then destroy their property.

They only have 'private property' because we agree they do. If they're hired to provide shelter, they should provide shelter.

And yeah, shelters suck. We need apartments everywhere, not just pigeonholed. Shelters don't give space for safe keeping items, places away from noise, and schedules of your own.

Most homeless are employed. And many unhoused choose that path because it lets them get employment. (But it's really really bad on mental health.)

-Crissa

 

[Zabhawkin]

Using the above video as a reference, Mind these are the 2170 cells but I doubt they would change the overall concept. Teslas battery packs are in a series parallel format, and are connected in bricks of 46 cells tied together in parallel. Then 96 bricks are connected in series. Each of the little aluminum wires doubles as a fuse to protect the pack from a cell going bad. This configuration gives quite a bit of reliability as the loss of one cell gives a 2.1% loss in capacity, but if you lose another cell in another brick it doesn't degrade the pack any further. The only time another bad cell will cause further degradation is when it happens in a brick that already has a bad cell.

What would going to 800v mean as far as the pack. Simply put twice as many bricks half as big. Same amount of total energy storage, half as many amps that it is able to deliver.

The only real difference you might find would be with DC fast charging. Much of the limitation for charging speed is the cable size and connector at the charger. Doubling the voltage at the same current doubles the amount of energy that can be delivered in the same amount of time. It is my understanding that the V3 charging cables are water cooled to deal with the heating.

Assuming the 4680 cells hold 5x the energy that would put the bricks on a 400v system to 9-10 cells, probably 9. A lost cell would cause an 11% loss of range. If it was increased to 800v 20% assuming a brick of 5. This is due to the fact that the BMS will still have to limit range to the lowest capacity brick.

Household charging would not be affected as the limitation is in the capability of the AC-DC charger in the car and the circuit in the house.

The reason it may work in the cybertruck is the pack is also going to be significantly bigger. Definitely for the Semi.

 

[ajdelange]

I do have a question on powerwalls. Do you really need 5?

Realized I didn't really answer your question fully. Again, I don't think my experience is going to be helpful to you because you are planning a residential space and I built a garage designed to charge 3 BEV (MX, Rivian and CT) of which I have only the X at the moment with doubts as to whether I will see either of the other two in my lifetime. Five Powerwalls hold 2/3 of the charge of the X battery and 1/3 the charge of the CT battery. Using historical data on solar collection and energy consumption on the garage on the main house (Including EV use) I ran simulations on the state of charge of the Powerwalls over time against 3, 4, 5,6... Powerwalls. Each added Powerwall gave better performance (fewer depletions), of course, but I am not King Midas so i decided 5 would do.

Thus far the 5 have proven more than adequate. I have not discharged below 80% (meaning 4 would have been adequate) but I have not driven much recently and the data comes from the transitional season (light heat pump load).

 

[Zabhawkin]

Realized I didn't really answer your question fully. Again, I don't think my experience is going to be helpful to you because you are planning a residential space and I built a garage designed to charge 3 BEV (MX, Rivian and CT) of which I have only the X at the moment with doubts as to whether I will see either of the other two in my lifetime. Five Powerwalls hold 2/3 of the charge of the X battery and 1/3 the charge of the CT battery. Using historical data on solar collection and energy consumption on the garage on the main house (Including EV use) I ran simulations on the state of charge of the Powerwalls over time against 3, 4, 5,6... Powerwalls. Each added Powerwall gave better performance (fewer depletions), of course, but I am not King Midas so i decided 5 would do.

Thus far the 5 have proven more than adequate. I have not discharged below 80% (meaning 4 would have been adequate) but I have not driven much recently and the data comes from the transitional season (light heat pump load).

I am going about it a different way, due to not having a Tesla solar installer in my state. But my calculations come out very similar to ajdelanges. I currently have 5kw solar with a 5kw grid tied inverter. My plans are to gradually add in another 5-7kw of solar and 50kwh of batteries. It would cover my day to day driving in a Cyber, and the occasional trip to the nearest city with most of the larger charging being done on the weekends while we are home straight off of the solar.

 

[ajdelange]

..my calculations...

Tip: Reckon electrical energy in hours full sun equivalent (hFSE). One hFSE is the capacity of your solar panels. This if you have 10 kW of solar panels one hFSE is equal to 10 kWh. Think of everything in hFSE. Your 50 kWh battery's capacity then becomes 5 hFSE. The battery size in the Trimotor CT is 20 hFSE. The final step is to go to the NREL charts/models which tell you how many equivalent full sun hours you get in a day.

 

[Zabhawkin]

Tip: Reckon electrical energy in hours full sun equivalent (hFSE). One hFSE is the capacity of your solar panels. This if you have 10 kW of solar panels one hFSE is equal to 10 kWh. Think of everything in hFSE. Your 50 kWh battery's capacity then becomes 5 hFSE. The battery size in the Trimotor CT is 20 hFSE. The final step is to go to the NREL charts/models which tell you how many equivalent full sun hours you get in a day.

Already have in my own way... in summer I get 6-8 hours worth of power. In the winter 4-5 hours.

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