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

[youtube]http://www.youtube.com/watch?v=4okOe1GV_OE[/youtube]

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

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

[youtube]http://www.youtube.com/watch?v=3nVf3ixOiVI[/youtube]
 
RegGuheert said:
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:

[youtube]http://www.youtube.com/watch?v=nUg7cDbRBo0[/youtube]

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
 
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.
 
drees said:
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 said:
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.
 
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.
 
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 said:
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 said:
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 said:
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.
 
drees said:
RegGuheert said:
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.
 
Enphase has announced that U.S.-based installers can now place orders for the AC Battery:
Enphase Energy Blog said:
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 said:
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.
 
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.
 
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.
 
RegGuheert said:
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.
 
drees said:
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.
 
drees said:
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
 
ltbighorn said:
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
 
wwhitney said:
ltbighorn said:
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.
 
RegGuheert on August 28 said:
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.
The price HAS managed to come down over the last eight months, but not by much:

Wholesale Solar: $1894 shipped

Based on previous calculations I have done, that puts the price of stored energy at about $0.30/kWh or higher. As such, this product is not there yet unless you happen to live in Hawaii. In that market, it might be worthwhile to help you install more solar without having to throttle production (since net-metering is a thing of the past there).

I expect Enphase will have better success selling batteries once they offer off-grid capabilities with the introduction of the IQ8-series and Ensemble.
 
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