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RegGuheert
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Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: The Enphase Energy Management System

Thu Oct 06, 2016 1:50 pm

drees wrote:
RegGuheert wrote:I cannot understand why the S-Series Micoinverters would be required to allow for this capability.

I believe that the footnote only relates to "power export limiting" since only the S series inverters presumably have the ability to limit their production to anything besides on/off.
That makes sense.

I was thinking in terms of using the Envoy-S together with the AC Battery to limit power export limiting, but based on your comment I can see that it really means limiting export power IN THE ABSENCE OF ANY AC BATTERIES. That could absolutely have value, particularly in locations where there is little or no value in exporting. In my case, I could have used this when I first turned on my system since my meter charged me for electricity flowing in EITHER direction. In that case, exporting electricity had NEGATIVE value, so I would have utilized this feature right away!

It is a bit interesting that there is no mention of this capability included on the datasheet for the S-series microinverters. Further, since I expect that the fourth-generation microinverters almost certainly employ digital control algorithms that they could be updated via firmware to provide the same feature. Assumedly Enphase has decided that it is not worth the engineering effort to implement such a feature on the older units.
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

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RegGuheert
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Re: The Enphase Energy Management System

Wed Feb 22, 2017 9:08 am

Enphase has announced that U.S.-based installers can now place orders for the AC Battery:
Enphase Energy Blog wrote:Enphase was first to market with a residential energy storage solution that holds UL certification for 2017 National Electrical Code standards. Like all Enphase technology, the storage system achieves industry-leading performance and safety.

Ready to get started? Contact your distributor to order the Enphase Storage System today.
Also, this is what a banner at the top of Enlighten has to say about the matter this morning:
Enlighten Banner wrote:Enphase is introducing new features for AC Battery and Self-suppy/No Export systems. Newly-installed Envoys will be upgraded automatically when connected to Enlighten.
I suppose that is referring to Envoy-S-based systems.
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

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RegGuheert
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Re: The Enphase Energy Management System

Mon Aug 28, 2017 6:54 am

Enphase AC Batteries are still priced WAY above the $1000 number that Enphase had put out there before the release. Here are a few prices from around the internet:

ACBattery.com: $2300 (must buy two) with free shipping
Wholesale Solar: $2275
FreeCleanSolar: $2250
eBay: $1850 plus $66 shipping

These prices do not include the mounting bracket, which the eBay vendor sells for $82 shipped.

It seems Enphase is pricing these things for early early adopters. I cannot see many of them moving until they can get the installed unit price down to around $1000.
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

ltbighorn
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Delivery Date: 08 Nov 2015
Location: SF Bay Area

Re: The Enphase Energy Management System

Mon Aug 28, 2017 6:34 pm

Hmm, California has a rebate program starting for batteries, but the initial program size is very small -- all swallowed up on the first day, largely by commercial installs. There's some talk of greatly increasing the funding and making more available to exclusively residential. It'd be nice if the Enphase batteries came down in price by then - I might consider it! If they're still in business.

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drees
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Re: The Enphase Energy Management System

Mon Aug 28, 2017 11:31 pm

RegGuheert wrote:Enphase AC Batteries are still priced WAY above the $1000 number that Enphase had put out there before the release. Here are a few prices from around the internet:
...
I cannot see many of them moving until they can get the installed unit price down to around $1000.

Honestly, with a Powerwall 2 holding 13.5 kWh and selling for $5500 and $1-2k for installation, Enphase has a long ways to go.

The Powerwall is just over $400 / kWh. With the Enphase AC Battery only holding 1.2 kWh, the rice has to come down to $500/ea to match Tesla. You need 10 of them to match the energy capacity of the Powerwall 2, and I'd have to guess that you could easily use at least 2x the amount of wall space.

If you want 27 kWh? The Powerwall 2 stacks so you just need another 6" or so of mounting depth.

To match Tesla's 5 kW of rated power, you'd need 18 Enphase AC Batteries. And don't forget you don't get off-grid backup with Enphase, either.

The only spec that Enphase handily beats Tesla on?

Efficiency - Enphase's 96% round-trip charge/discharge efficiency is far superior than Tesla's 89%. Tesla should do better.
'11 LEAF SL Powered By 3.24 kW Enphase Solar PV

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RegGuheert
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Re: The Enphase Energy Management System

Tue Aug 29, 2017 1:42 am

drees wrote:The only spec that Enphase handily beats Tesla on?

Efficiency - Enphase's 96% round-trip charge/discharge efficiency is far superior than Tesla's 89%. Tesla should do better.
In reality, the efficiency of the AC Battery is probably not any higher than Tesla's Powerwall efficiency. 96% is the efficiency of the battery only. To get back to AC, you need to go through the inverter twice, which is specified to have a peak one-way efficiency of 97.3%. That gives a peak efficiency of 0.96*0.973*0.973 = 0.908 or 90.8%.

I had thought the AC Battery would be more durable than the Powerwall, but that was before Tesla retained Jeff Dahn to work on their chemistry. He claimed that he had more than doubled the life of their battery within the first year of the contract. Still, I suspect that the AC Battery still has the edge with 7600 95% DOD cycles guaranteed.
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

wwhitney
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Location: Berkeley, CA

Re: The Enphase Energy Management System

Tue Aug 29, 2017 7:25 am

drees wrote:If you want 27 kWh? The Powerwall 2 stacks so you just need another 6" or so of mounting depth.

My understanding is that for horizontally stacked Powerwalls, they need to be supported on the ground, you can't wall mount two of them.

Cheers, Wayne

wwhitney
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Re: The Enphase Energy Management System

Tue Aug 29, 2017 7:30 am

ltbighorn wrote:Hmm, California has a rebate program starting for batteries, but the initial program size is very small -- all swallowed up on the first day, largely by commercial installs.

Your info is a little off. The program is called SGIP, Self Generation Incentive Program, and includes using batteries for time shifting. The funding is split into three categories: generation, large scale storage, and small scale storage. It is released in a series of 5 steps, with declining rebate rates in each step. Both large scale storage and small scale storage filled their 1st step very quickly and are now in steps 2 or 3. Generation is still in step 1.

For more info on the status of the funding, see: https://www.selfgenca.com/home/program_metrics/

Cheers, Wayne

ltbighorn
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Re: The Enphase Energy Management System

Wed Aug 30, 2017 6:24 pm

wwhitney wrote:
ltbighorn wrote:Hmm, California has a rebate program starting for batteries, but the initial program size is very small -- all swallowed up on the first day, largely by commercial installs.

Your info is a little off. The program is called SGIP, Self Generation Incentive Program, and includes using batteries for time shifting. The funding is split into three categories: generation, large scale storage, and small scale storage. It is released in a series of 5 steps, with declining rebate rates in each step. Both large scale storage and small scale storage filled their 1st step very quickly and are now in steps 2 or 3. Generation is still in step 1.

For more info on the status of the funding, see: https://www.selfgenca.com/home/program_metrics/


Thanks. Sounds like the changes I mentioned have happened in 2017. As I understand it, in 2016 there wasn't a set aside for residential generation. Pretty much all residential installers reported that the entire pool oversubscribed by large projects within a few minutes of applications opening (all funds being made potentially available on a single day), and the funding itself being smaller as funds went to other state incentives like fuel cells. The new/current situation sounds much better.

Something odd in the requirements for SGIP seems to be the requirement that residential systems discharge 52 * the storage capacity to the grid per year. Guessing this is some sort of measure to try and keep residential users from sizing their batteries too large and instead keep it aimed towards load shifting, but that's just a guess. Not sure how they measure it - probably just net export over the course of the year?

I haven't run the numbers in detail, but with Enphase's pricing, California's excellent NEM terms, and E-6 TOU rates being good for a few more years, it still seems like a bit of a tough sale, even with SGIP incentives.

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