Becky50
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Re: Tesla Powerwall

Mon May 16, 2016 8:47 am

Thanks for sharing. I am looking forward to the day that we can install one of these Tesla wall storage units.

smkettner
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Re: Tesla Powerwall

Mon May 16, 2016 9:10 pm

I had only seen them displayed inside. I have more space outside actually. Nice to see this get started.
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RegGuheert
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Re: Tesla Powerwall

Sun Jul 03, 2016 4:12 am

It seems the capacity warranty for the Tesla Powerwall still lasts for ten years, but has been reduced to 60% or 18 MWh at that point: Tesla Energy's Incredible Shrinking Powerwall Warranty.

That's a bit better than the LEAF's battery capacity warranty since it guarantees 72% at five years (and Tesla's goes to ten). OTOH, 18 MWh only comes to 2800 full cycles (at the full 6.4 kWh capacity). That warranty pales when compared to the warranty Enphase offers for the AC Battery, which is 80% capacity retention at 10 years or 7300 cycles.

So, let's see how they stack up in terms of US$/kWh (discharge):
- Tesla Energy: US$3500/18,000 kWh = US$0.194/kWh (Assumes Tesla meets their price and excludes the price of the inverter.)
- Enphase Energy: US$1000/(7300*1.2 kWh*0.95*0.9*0.9) = US$1000/6740 kWh = US$0.148/kWh (1.2 kWh, 95% usable capacity, 90% round-trip efficiency, 90% average capacity over life, inverter included, Envoy excluded, assumes all 6740 kWh is used within the cycles OR Enphase bases warranty on total energy discharged, both of which are unlikely)

Of course, the Tesla offering supports off-grid application while the Enphase product is grid-tied only. IMO, Tesla will have difficulty competing with lead-acid in off-grid applications due to price and will likewise have difficulty competing with Enphase for time-shifting grid-tied applications. Elon will need to really talk this this one up to try to get it to sell.
RegGuheert
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QueenBee
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Re: Tesla Powerwall

Sun Jul 03, 2016 4:15 pm

RegGuheert wrote:That's a bit better than the LEAF's battery capacity warranty since it guarantees 72% at five years (and Tesla's goes to ten).

If we assume the old chart about the capacity bars is still correct it's more like 66% or if we assume that SOH represents the capacity it's more like 62-65%.

TimLee
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Re: Tesla Powerwall

Mon Jul 04, 2016 3:00 pm

QueenBee wrote:
RegGuheert wrote:That's a bit better than the LEAF's battery capacity warranty since it guarantees 72% at five years (and Tesla's goes to ten).

If we assume the old chart about the capacity bars is still correct it's more like 66% or if we assume that SOH represents the capacity it's more like 62-65%.

Andy Palmer confirmed at the Saturday August 24, 2013 Phoenix dinner that the service manual chart was correct.
15% for the first capacity bar, around 6% (6.25% listed in first manual) for the remaining bars.
See viewtopic.php?f=4&t=13192&start=380#p320953.

But as you point out SOH and % capacity do appear to have to drop to more like 61% or 62% and be there for two or three weeks in warm weather for the eighth capacity bar to drop.

Was my experience in early June at about five years and two weeks from LEAF in service date. Another three months more from manufacture date.

Tim Lee
Chattanooga, TN

Man. Date: 03/10/11, VIN # 2026
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RegGuheert
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Re: Tesla Powerwall

Thu Nov 03, 2016 10:34 am

Tesla recently announced their new Powerwall 2 product. Interestingly, they have changed from offering a DC-coupled product to an AC-coupled product, more inline with what Enphase is offering with their AC Battery. Here are the technical specifications:

Tesla wrote: Usable Capacity
13.5 kWh
Depth of Discharge
100%
Efficiency
90% round-trip
Power
7kW peak / 5kW continuous
Supported Applications
Solar self-consumption Time of use load shifting Backup Off grid
Warranty
10 years
Scalable
Up to 9 Powerwalls
Operating Temperature
-4° to 122°F / -20°C to 50°C
Dimensions
L x W x D: 44" x 29" x 5.5" (1150mm x 755mm x 155mm)
Weight
264.4 lb / 120 kg
Installation
Floor or wall mounted Indoor or outdoor
Certification
UL and IEC certified Grid code compliant
As you can see, they have doubled the usable energy and nearly quadrupled the power capability. Price is now 1/2 the price of the Enphase AC Battery on a per-kWh basis (but that is in Elon-dollars, which are often quite a bit lower than real dollars). Frankly, this product looks significantly more attractive than the previous version.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

mxp
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Re: Tesla Powerwall

Thu Nov 03, 2016 11:17 am

Sorry for the noobie question:

With this battery installed in home, how does the customer disengage from the Grid (i.e. the utility company) and use the battery solely? Will Tesla install some kind of switch for end-user to engage or dis-engage from utility grid/battery ?

Ideally, I would like to charge the battery overnight (low cost) and in the daytime, disengage from the utility grid.
Did Tesla develop an agreement with local utility companies for these systems?

I recall a couple of years ago, I was reading about V2G products on this forum and it seems, any V2G system did not make it into the US market due to local utility companies not desiring to lose out to these systems.


RegGuheert wrote:It seems the capacity warranty for the Tesla Powerwall still lasts for ten years, but has been reduced to 60% or 18 MWh at that point: Tesla Energy's Incredible Shrinking Powerwall Warranty.

That's a bit better than the LEAF's battery capacity warranty since it guarantees 72% at five years (and Tesla's goes to ten). OTOH, 18 MWh only comes to 2800 full cycles (at the full 6.4 kWh capacity). That warranty pales when compared to the warranty Enphase offers for the AC Battery, which is 80% capacity retention at 10 years or 7300 cycles.

So, let's see how they stack up in terms of US$/kWh (discharge):
- Tesla Energy: US$3500/18,000 kWh = US$0.194/kWh (Assumes Tesla meets their price and excludes the price of the inverter.)
- Enphase Energy: US$1000/(7300*1.2 kWh*0.95*0.9*0.9) = US$1000/6740 kWh = US$0.148/kWh (1.2 kWh, 95% usable capacity, 90% round-trip efficiency, 90% average capacity over life, inverter included, Envoy excluded, assumes all 6740 kWh is used within the cycles OR Enphase bases warranty on total energy discharged, both of which are unlikely)

Of course, the Tesla offering supports off-grid application while the Enphase product is grid-tied only. IMO, Tesla will have difficulty competing with lead-acid in off-grid applications due to price and will likewise have difficulty competing with Enphase for time-shifting grid-tied applications. Elon will need to really talk this this one up to try to get it to sell.

garsh
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Re: Tesla Powerwall

Fri Nov 04, 2016 3:45 am

mxp wrote:With this battery installed in home, how does the customer disengage from the Grid (i.e. the utility company) and use the battery solely?
Generally, no. If one wanted to do this, one would probably need to purchase several powerwall batteries, along with lots of solar panels for charging them.
Will Tesla install some kind of switch for end-user to engage or dis-engage from utility grid/battery ?
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).
Ideally, I would like to charge the battery overnight (low cost) and in the daytime, disengage from the utility grid.
Indeed, that's how most owners make use of the powerwall. In addition, it provides a whole-house UPS for when the power goes out.
2012 Black SV w. G35 wheels, 9 bars, 85,000 miles

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LTLFTcomposite
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Re: Tesla Powerwall

Fri Nov 04, 2016 6:19 am

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?
LTL
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Graffi
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Re: Tesla Powerwall

Fri Nov 04, 2016 12:06 pm

LTLFTcomposite wrote: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?


Anytime there is power generation connected to the grid there must be a cut-off switch. You can not have solar or other power sent back through the grid if the power company shuts power down to do maintenance. This switch is included with the powerwall.

Several years ago the utility company shut down our solar (switch box next to the main line into our house) so they could do maintenance in our area. The problem was that when they finished no one came back to switch it back on. Almost two months later we got a large electric bill and found out the solar was turned off. For a long time we logged into the utility account daily to make sure our solar was sending power to the grid. Lesson Learned.
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