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RegGuheert
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Leaf Number: 5926
Location: Northern VA

Re: The Enphase Energy Management System

Sun May 15, 2016 6:40 am

Here is a YouTube video from Enphase showing a single electrician installing four AC Batteries (4.8 kWh) in 1 hour 40 minutes:



I find it funny that the installer's name is Nick Soleil. :)

ETA: FWIW, here's another marketing video on the AC Battery:

RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 3K 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

Thu Aug 18, 2016 2:43 am

RegGuheert wrote:Here is some additional information about the battery technology directly from the manufacturer:
It seems that sometime after I added this link, Eliiy has added a video which shows both a nail penetration test and a crush test for the battery they are providing for the Enphase AC battery:



I have to say that the more I look at this solution, the more I like it better than the Tesla battery. Here are the trade-offs as I see them now:

Tesla Powerwall benefits:

- Provides backup capability when combined with a PowerEdge inverter
- Thinner (Sticks out from the wall less.)

Enphase Energy AC Battery benefits:

- Lower cost per kWh of energy stored
- Higher round-trip energy efficiency (AC Out/AC In)
- Safer (I'll hold this opinion until I see a similar video for the Powerwall which indicates otherwise)
- Easier to install (Assuming Envoy-S install is not too challenging)
- Longer life (I expect this will function for many more years before needing a replacement)
- Allows both lower AND higher amounts of energy storage (SolarEdge only allows a single Powerwall)
- Works with ANY PV system or even with none
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 3K 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
Posts: 5375
Joined: Mon Mar 19, 2012 4:12 am
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Location: Northern VA

Re: The Enphase Energy Management System

Sun Aug 21, 2016 5:44 am

Here is an Enphase blog post talking about wrapping up the beta program and getting ready to ship the AC batteries in Australia. Included there are links to two interesting pieces of collateral:

- Storage Essentials for Installers E-book
- AC Battery Quick Install Guide
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 3K 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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drees
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Re: The Enphase Energy Management System

Sun Aug 21, 2016 10:49 am

Still in beta?

Didn't they announce this product like two years ago?

I still question the low capacity of each unit. 2-3 kWh per unit would be much more usable and should reduce overall costs. I can't imagine anyone wanting less than 5-6 kWh. Given the advances in battery tech the last two years they should be doing 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

Sun Aug 21, 2016 11:50 am

drees wrote:I still question the low capacity of each unit. 2-3 kWh per unit would be much more usable and should reduce overall costs. I can't imagine anyone wanting less than 5-6 kWh. Given the advances in battery tech the last two years they should be doing better.
While I agree that almost no one needs just 1.2 kWh, I think there are two issues which are more important than the absolute size of battery: durability of the battery and energy-to-power ratio. Let's look at both:

Durability: It seems clear that Enphase has chosen a more durable battery than Tesla and this fact is reflected in their respective warranties. The end result is that the lifetime costs of the AC Battery are on the order of 1/2 that of the Powerwall.

Energy-to-Power Ratio: This ratio is important in the following ways:

1) It determines the maximum rate at which the battery can be charged or discharged. That rate is equal to C/Energy-to-Power Ratio.
2) It determines the minimum amount of storage you must purchase in order to get a particular amount of power capbility.
3) Alternatively, it determines the minimum power level that you must purchase to get a given quantity of storage.

So let's compare the two products:

Tesla Powerwall: 7 kWh/2 kW = 3.5 hours
Enphase AC Battery: 1.2 kWh/0.27 kW = 4.4 hours

Basically, both companies have chosen about the same ratio. While I haven't done the analysis myself, my guess is that this ratio has been determined to be the best compromise for the initial target market.

In Enphase' case, they have limited flexibility when it comes to the power of the inverter, as it appears their goal is to maximize their use of their standard inverter technology. Perhaps they have decided that 1.2 kWh is the largest battery that they can reasonably sell with a 270-W inverter.

I also think Enphase designed their product in order to ensure the weight was not beyond a particular value. The ease of single-person installation is a very attractive aspect of the Enphase product.

As time marches on, I imaging that both products will become available with both higher or lower Energy-to-Power Ratios.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 3K 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
Posts: 5375
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Re: The Enphase Energy Management System

Fri Aug 26, 2016 6:36 am

This article on Enphase' ongoing financial woes indicates that Enphase already had pre-orders in Australia for 70,000 AC Batteries as of early July:
GreenTechMedia wrote:Just last week at Intersolar in San Francisco, CEO Paul Nahi told GTM's Jeff St. John, "We have preorders for 70,000 of our battery and energy management systems in Australia alone."
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 3K 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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drees
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Re: The Enphase Energy Management System

Sat Aug 27, 2016 8:54 am

RegGuheert wrote:This article on Enphase' ongoing financial woes indicates that Enphase already had pre-orders in Australia for 70,000 AC Batteries as of early July

Great article on Enphase overall. They really must be feeling the pressure over there. Their cost reductions are impressive, aiming for $0.15/W next year and $0.10/W by 2018.

That's $45 and $30 respectively for a 300W inverter. Probably manufacturing prices, so that probably puts wholesale prices around $65 / $40.

That's an amazing cost reduction over the current product line.
'11 LEAF SL Powered By 3.24 kW Enphase Solar PV

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

Re: The Enphase Energy Management System

Sun Aug 28, 2016 3:00 am

The relatively small increments (1.2kWh) and the ability to work with any solar install/no solar (given that the majority of installs outside there, particularly outside the US are not Enphase) seem like major wins for the Enphase AC battery. The two-daily cycles rating also increasing the effective kWh for people who have morning peak costs.

Personally I would like if they had a model that was a bit narrower and could fit between studs, but then out here many garages have unfinished walls and it's a nice way to save space. Don't expect to see this of course since most building/code standards now finish the walls even in a garage.

That was a great article and it's encouraging to hear they have so many preorders. Seems like the utilities are their worst enemy in accelerating their own decline. They behave punitively towards solar installs, ostensibly because they need to cover the fixed costs of running the infrastructure on reducing energy sales, but those punitive actions just accelerate the financial viability of storage systems which will dramatically increase their woes.

Regarding the ease of an Envoy-S Metered install, it's certainly more work than a non-metered one (which is just a matter of plugging it into an outlet), but it's nothing too complex. The most unusual requirement is for a non-metallic 3R enclosure with protected conduits, which I'm pretty sure comes from the desire to not interfere with the built-in wifi connectivity. It mounts in a few seconds and needs hardwired powered and 3 CTs. In a load panel with enough space for the snap-on CTs (they're not particularly large), this takes only a few minutes once the conduit is in place. Biggest issue would be in panels that are super-tight.

Hope they're successful on their cost cutting schedule. Only extra question mark there for me is whether SolarEdge's HD Wave technology will substantially drop their costs, making 10 cents/watt not as competitive as they hope.

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RegGuheert
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Re: The Enphase Energy Management System

Mon Oct 03, 2016 8:58 am

Enphase has released a preliminary datasheet for the AC Battery.

There was one statement on the datasheet that I found particularly surprising:
Enphase AC Battery Datasheet wrote:Services Maximizing self-consumption of solar, time-of-use bill management, power export limiting2
That superscript 2 at the end is for a note which reads:
Enphase AC Battery Datasheet wrote:2. Optional. requires Enphase S-Series Microinverters™ to implement.
I see that this statement was there on the previous version of the datasheet which I had downloaded, but still I don't get that limitation at all, particularly since Enphase has talked all along about how the Envoy-S would allow the AC Battery to be integrated with ANY PV system, even if it used completely different inverter technology.

But even if you ignore that bit of marketing, I cannot understand why the S-Series Micoinverters would be required to allow for this capability. Do you REALLY need to change the phase of the current to allow the batteries to maximize self-consumption of your PV? I really don't think phase angle has anything to do with it, so I don't see why this new requirement exists.

So does Enphase expect their existing Hawaiian customers to sell all of their M190-, M215- and M250-based systems and purchase S230s or S280s just to make their AC Batteries work? Or are the existing customers grandfathered in so this is just an allowance for Hawaiian Electric to ensure as many power-factor and ride-through capable inverters are installed as possible?
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 3K 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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drees
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Re: The Enphase Energy Management System

Wed Oct 05, 2016 12:57 am

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.
'11 LEAF SL Powered By 3.24 kW Enphase Solar PV

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