Tesla Wants to Build a Battery for Your House

[donald]

I'm not looking to compare on-grid to off-grid; I'm looking at whether a generator-only off-grid is more cost effective than using a PV-battery system with a generator. I'm just curious how the numbers compare at current prices.

I wonder about this too. But I expect for this to work requires an expensive low rpm diesel that is amortized over many years. So large upfront costs. What they do in Alaska is always a good place to look at off grid without solar.

I wouldn't want to maintain and repair a Honda generator that runs four hours a day. "Cost Effective" can quickly become an undesirable situation. Batteries have undesirable characteristics. But moving parts (engines and windmills) are often worse.

[SmartElectric]

A good 5 year battery to give you 1 usable Kwh per day is going to cost you $1200

Or you could just buy the Tesla Powerwall, 7kWh costs you $3K.
Ref:

http://www.teslamotors.com/powerwall

The price of battery power for solar installations just dropped by >2x today.

[SunEagle]

Or you could just buy the Tesla Powerwall, 7kWh costs you $3K.
Ref:

http://www.teslamotors.com/powerwall

The price of battery power for solar installations just dropped by >2x today.

Before you start to push for that new battery you really need to get more details then just the price, kWh rating and warranty period.

Cycle count based on DOD % will give you a better idea on how long it will really last. Can it be used for deep cycling applications or is it really designed for brief discharge periods a few times a week. Big difference in the way it would be used by off grid people.

[Willy T]

Before you start to push for that new battery you really need to get more details then just the price, kWh rating and warranty period.

Cycle count based on DOD % will give you a better idea on how long it will really last. Can it be used for deep cycling applications or is it really designed for brief discharge periods a few times a week. Big difference in the way it would be used by off grid people.

The Voltage alone should tell you that it wasn't designed for Off-Grid.

[SunEagle]

The Voltage alone should tell you that it wasn't designed for Off-Grid.

That 350 to 450 range must be the DC voltage which means you still need some type of inverter to get your 120/240AC home power. That type of inverter will put the "system" cost a lot higher then using FLA batteries with a standard inverter making the cost/kWh much higher.

[donald]

That type of inverter will put the "system" cost a lot higher then using FLA batteries with a standard inverter making the cost/kWh much higher.

So what? Ten years of off grid for $10K with no maintenance batteries would be a godsend.

[SunEagle]

So what? Ten years of off grid for $10K with no maintenance batteries would be a godsend.

I seriously think they will not last in an "off grid" application for ten years.

[J.P.M.]

Being an early adoptor comes with risks. I'd wait at least 2-3 years after serious roll out and see what develops.

[donald]

These packs wont be warrantied for off grid either. But that not the point. The point is the cost of lithium based battery systems. I can order a sophisticated 30 kwh of battery system from a credible company for $10K. This is finally a fundamental change in the economics and practicality of home scale storage.

Plenty of companies will build inverters for 350v DC. Is there any reason these inverters will be more expesive to build than todays standard inverters?

What voltage does tesla's dc motor use?

[SunEagle]

These packs wont be warrantied for off grid either. But that not the point. The point is the cost of lithium based battery systems. I can order a sophisticated 30 kwh of battery system from a credible company for $10K. This is finally a fundamental change in the economics and practicality of home scale storage.

Don't forget the cost of that inverter which accepts 350 to 450 VDC which might not be cheap. You might find that they are only sold by Tesla since they make them for their cars.

[Sunking]

So what? Ten years of off grid for $10K with no maintenance batteries would be a godsend.

So please tell us exactly where to find a Charge Controller and Inverter made to work with a 450 volt battery? Please tell godsend to answer. Inverters can be found, but battery Inverters made in in that voltage range are usually measured in MW, not KW. No such thing as a 450 volt charge controller.

[donald]

So please tell us exactly where to find a Charge Controller and Inverter made to work with a 450 volt battery? Please tell godsend to answer. Inverters can be found, but battery Inverters made in in that voltage range are usually measured in MW, not KW. No such thing as a 450 volt charge controller.

Charge controller included: "Single phase and three phase utility grid compatible." Certainly you understand that Tesla needs to integrate the charge controller. This is a system, not a battery.

Do you think Tesla just forgot this system will need an inverter? It doesn't seem to be included. But the beta systems installed to date seem to have the inverter from tesla.

[Sunking]

What voltage does tesla's dc motor use?

LOL. Tesla does not use a DC motor. They use a 3-phase AC Induction Motor operating @ 32 Khz @ 400 volts using 6831 batteries. The battery is good to about 500 cycles with a 8 year warranty.

[Amy@altE]

From Tesla's press package, they partnered with SolarEdge for the inverter:

SolarEdge, a leader in the global PV inverter market, and Tesla partnered for the joint development of a PV storage and backup power solution for the worldwide residential solar market. Building on SolarEdge’s proven DC optimized inverter proven and Tesla's leading automotive-grade battery technology, the solution will require only a single SolarEdge inverter to manage both PV and storage functions. The system is designed for efficient, outdoor installation and includes remote monitoring and troubleshooting to keep operations and maintenance costs low.

From an old 2014 press release from SolarEdge:

In addition, the company will present StorEdge™, its innovative storage solution that employs optimized battery pack based on SolarEdge’s widely-deployed and field-proven power optimization technology. StorEdge™ has an increased lifespan and is a safe, highly efficient, and scalable solution. Available later this year, StorEdge™ will be able to be added to existing SolarEdge inverters.

“Around the world, SolarEdge’s module-level power optimization has become a standard technology in residential and commercial systems because of its proven financial benefits,” stated Guy Sella, CEO and Chairman of SolarEdge. “The benefits provided by power optimization will provide SolarEdge a strong foothold in the self-consumption market. We see this introduction further increasing SolarEdge’s PV market penetration.”

[jimqpublic]

Inverter not included per the telecast.

Musk sounded a bit like a movie villain. I like him more for it.

I have a 20 year net metering agreement and very few outages (probably total of 12 hours in 23 years) so no real interest in batteries, but I could see this being good for a place with high peak prices and no net metering.