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PowerWall and "The Missing Piece..." Event

zibaji

Member
Apr 8, 2015
5
0
I have been offered by solar city tesla battery back up in California that is charged with your solar system. Cost is around 23k and PGE. Rebate is $8k plus. Solar city charge $1500 upfront for install and then $15/ mo for 10 years lease. I need to sign papers this week and I doubt Tesla battery will be any cheaper?
 

AnOutsider

S532 # XS27
Moderator
Apr 3, 2009
11,957
210
It will work until enough people start using this system. That could be a long enough time to get a payback. Life is full of gambles but that is one I will take.

Plus, for some like me, it's about becoming that much more self-reliant. We don't have TOU rates here, but it would be nice to have power during outages, and perhaps eventually go grid-less
 

beeeerock

Active Member
Mar 12, 2015
1,515
435
Kamloops BC Canada
Hydro-electric power generation is relatively good at absorbing demand changes day to night... modify how much water flows through and your generation power changes. However, with thermal plants (whether fired by coal, oil or even nuclear), you can't just spool them up in a matter of seconds or minutes. The result is an energy-wasting buffer being maintained at the low times to ensure high demand can be met.

If society can adjust their consumption habits, including installing 'shock absorbers' as the battery systems would be, peaks and valleys in demand could be flattened out, resulting in more efficient thermal generation.
 

kptesl

Member
Feb 22, 2014
50
11
US
I think it will be stationary battery pack but more. What could a battery pack offer?
1) backup power (nice but boring)
2) off peak power use (great but limited value, can't justify cost of pack)
3) rapid discharge for in-home SUPERCHARGING!!!!!

think about it- the car could support it, but home electrical systems can't pull that much load. A battery could and it would certainly be useful for people that might need to drive all day- like chauffeurs, realtors etc.
 

thegruf

Active Member
Mar 24, 2015
2,308
2,106
indeterminate
I think it will be stationary battery pack but more. What could a battery pack offer?
1) backup power (nice but boring)
2) off peak power use (great but limited value, can't justify cost of pack)
3) rapid discharge for in-home SUPERCHARGING!!!!!

think about it- the car could support it, but home electrical systems can't pull that much load. A battery could and it would certainly be useful for people that might need to drive all day- like chauffeurs, realtors etc.

3) - I was keeping that one to myself ;)
4) home based battery swap - lol

5) not telling :p

Somehow there has to be an ROI justification
 

SteveG3

Active Member
Supporting Member
Sep 21, 2012
4,013
15,450
US
I think it will be stationary battery pack but more. What could a battery pack offer?
1) backup power (nice but boring)
2) off peak power use (great but limited value, can't justify cost of pack)
3) rapid discharge for in-home SUPERCHARGING!!!!!

think about it- the car could support it, but home electrical systems can't pull that much load. A battery could and it would certainly be useful for people that might need to drive all day- like chauffeurs, realtors etc.

To this point Tesla has sounded disinterested in vehicle to grid use of the vehicles battery pack anytime soon. I'm not sure why... my best guess is they don't want all those extra discharge cycles muddying how resilient the battery is to degradation and messing up the growth of public enthusiasm for EVs with a distorted perception of the lifetime of the battery.

What if the home storage unit somehow allows Tesla to offer the use of the stored energy in the car for backup power in the event of an outage, but is designed to block use of the car's battery to do vehicle to grid. This would mean a modest costing 10 kWh battery in the home could actually offer 80 to 100 kWh of backup power (get you through a week or more of keeping essentials running in a blackout), but avoid accelerated battery degradation and public perception that EV batteries need frequent costly replacement. I don't know what other equipment/cost would be involved in setting it up, but a 10 kWh battery could sell for as little as $3K. If the other equipment were $2K or less, I'd say $5K would be a pretty good price for over a week's backup power vs. $10K I understand a backup generator to cost. If this would be possible, it would make the car and the stationary storage product both sell better.
 

MartinAustin

Active Member
Jul 21, 2013
2,857
13,266
Austin, Texas USA
The in-home rapid car charging is a great stretch-goal. I can't imagine it happening just yet, but I will be delighted to be wrong. The power transfer is very great, and the inefficiencies generate a lot of heat. The Supercharger's mechanism has massive fans and make a lot of noise when you're charging your Model S from it. Will this same noise be acceptable in a home? I suppose if it is outside the house, and it's no more noisy than an AC compressor, it might be OK. But I am still leary of the heat.

The Model S has fans to disseminate battery heat during supercharging. If you live in cold climates you won't have a problem, but in Texas, people's enclosed garages can often have 85 degrees ambient temperature during the height of summer - and that's before you start to charge! Once charging starts, and you have a car and/or home battery venting hot air into the garage, the ambient temperature in the garage will rise. This is the scenario that leads me to believe in-home supercharging from the Tesla Home Battery is not going to happen. But like I said, I'll be delighted to be wrong, and if there is one company that knows how to charge batteries under all circumstances, it's Tesla Motors.
 

ItsNotAboutTheMoney

Well-Known Member
Jul 12, 2012
11,187
9,061
Maine
I think it will be stationary battery pack but more. What could a battery pack offer?
1) backup power (nice but boring)
Expensive back-up, but would likely come with automatic switching which you don't get with a cheap generator.

2) off peak power use (great but limited value, can't justify cost of pack)
Depends on where you live.

3) rapid discharge for in-home SUPERCHARGING!!!!!

think about it- the car could support it, but home electrical systems can't pull that much load. A battery could and it would certainly be useful for people that might need to drive all day- like chauffeurs, realtors etc.

Tesla uses a max C-rate of C/2, so a 10kWh pack would only give you 5kW. You'd need a huge pack to get decent DC. Also, to be able to do DC charging from the pack, the pack would have to be located within a short distance of the car. And then having the separate connection would add cost.

Dear World,

Tesla is going to do a home battery solution, that could be used to provide outage back-up, and/or storage of solar, and/or peak shaving. Tesla wants more battery demand so it can persuade Panasonic and, more importantly, Panasonic's partners to invest aggressively in the Gigafactory.

Nothing more than that. No Supercharging. No V2G.
 

SteveG3

Active Member
Supporting Member
Sep 21, 2012
4,013
15,450
US
Tesla is going to do a home battery solution, that could be used to provide outage back-up, and/or storage of solar, and/or peak shaving. Tesla wants more battery demand so it can persuade Panasonic and, more importantly, Panasonic's partners to invest aggressively in the Gigafactory.

Nothing more than that. No Supercharging. No V2G.

do you think there is some possibility of tapping into the vehicles battery for outage back-up but not V2G (nor any other purpose)? it would be pretty awesome to pay for 10 kWh of back up capacity and access 80 to 100 kWh of back up capacity via your Tesla.
 

Cattledog

Active Member
Supporting Member
Feb 9, 2012
2,277
3,832
San Antonio, TX
Predictions in Order of Likelihood:

1. Stationary Storage - Best scenario: Announce deal at utility or large corporation level in addition to Solar City
2. E-Motorcycle/Scooter - Best Scenario: Announce manufacturing deal in China
3. Large Fleet Makeover to Electric - Best Scenario: Announce deal with UPS or FedEx (UPS has 100k vehicles)
4. Model X Reveal - Best Scenario: That's how we interpret "it's not a car"
 

Beckler

Member
Oct 22, 2012
607
595
Canada
I'm pretty sure I know what this will be. You'll note 'shop.teslamotors.com' is missing a category: Food. Pizza, in particular. Ordering a Model S is essentially like ordering pizza anyway, with delivery, so they're already set up for that. Also Design studio already talks about 19", 21" wheels, so they can just replace that one word.
 

MorrisonHiker

Well-Known Member
Moderator
Mar 8, 2015
10,475
10,408
Colorado
do you think there is some possibility of tapping into the vehicles battery for outage back-up but not V2G (nor any other purpose)? it would be pretty awesome to pay for 10 kWh of back up capacity and access 80 to 100 kWh of back up capacity via your Tesla.

The problem that I see with this is that it could cause people to abuse the use of Superchargers. If the power was out, many would try to use the Superchargers to recharge their car batteries and then power their homes. Software could probably be used to prevent or discourage this by tracking how the power was used (driving vs. power outage output).
 
I was out of power for about 18 hours after a thunderstorm swept through our area the other day. Had it been the middle of Summer I would have paid top dollar for a backup battery. From what I understand this battery will supply a house with power for a couple of days during an outage. I also read that the cost of the backup pack is going to be in the neighborhood of $3K. If so, I would definitely get one but I am afraid that the installation of the backup battery is going to be limited to those areas that are serviced by Solar City. I was looking into getting a residential solar system and was told that they do not service my area. So...this "news" that is going to be delivered by Elon on April 30th will more than likely be a non-event for me and many others.
 

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