Zero feed into grid with Enphase?

[rickj]

The M250 installation manual http://enphase.com/sites/default/fil..._Manual_NA.pdf says:

"NOTE: When inter-connecting to grids managed by Hawaii Electric Industries (HEI), including HECO, you must select an appropriate grid profile for your installation. You can set the grid profile through Enlighten, during system registration, or through Installer Toolkit at any time. You must have an Enphase Envoy communications gateway to set or change the grid profile. For more information on setting or changing the grid profile, refer to the Envoy or Envoy-S Installation and Operation Manual at enphase.com/support."

I found https://www.hawaiianelectric.com/cle...upply-programs with a list of "qualified equipment": https://www.hawaiianelectric.com/Doc..._equipment.pdf. The S-series is listed as CSS (customer self service = zero feedback) capable, the M250 is not.

[ButchDeal]

You are using an Outback Radian, Butch, correct?

I do not have a radian though we sell them. Mine is a flexpower 1 based GT

[BackwoodsEE]

OutBack is very clear about the size of the battery being large enough to handle the full charge from the AC coupled system. A small LiFePo4 is unlikely to handle that.
an AGM might if not too small but the heavy cycling would likely kill it shortly.

You are using an Outback Radian, Butch, correct? I have a lot to learn about them before getting one, perhaps some of it from you. I've read some of your postings previously.

Let's say the sum grid-tie inverter output is 6 kW, near 80% of the Radian's 8 kW capacity. If all that got converted to 50V DC for a charging battery assuming for the sake of discussion that there were no losses, you'd have 120 A of charging current. For an AGM or LiFePo4 I understand that C/4 is OK, maybe even C/3, so that would mean a battery in the upper 400 Ah range. Yeah, I guess that's not exactly small, is it? Even doing C/3 with a LiFePo4 would be a very expensive (around $8000 for CALBs) 360 Ah.

Ouch. Batteries suck.

The cycling you're referring to--does that also happen when AC coupling in grid-tie mode (not an option for the OP, I know)? I'd hope the Outback is smart enough to leave the battery alone when it has the grid to feed to and draw from.

[jflorey2]

One possibility would be to AC couple your microinverters to an Outback Radian operating in grid-zero mode. (Outback has an informative web page on this.) You could use a relatively small AGM or LiFePo4 battery, just enough to let the Radian hybrid inverter slosh current back and forth as it keeps up with your loads and turns the microinverters on and off in response to the loads.

Your batteries need to be larger than the smallest increment of inverters. For example, if you have 5 groups of 2kW each, the batteries must be able to accept at least 2kW (i.e. 42 amps.) And then, of course, you need 5 outputs from the inverter to drive the relays for those groups; those outputs currently do not exist.

[ButchDeal]

Apparently the Enphase inverters are very good at monitoring phase and voltage of the grid the are connected to, and shutdown very quickly if the specs are not met.

All grid tie inverters can do this.

Many systems have the capabilities of zero grid feed in.
SolarEdge seems like the best fit since you are considering micros. It is built in and works well.

Any hacked system is unlikely to meet code or be approved as a zero feed in solution.

[rickj]

One possibility would be to AC couple your microinverters to an Outback Radian operating in grid-zero mode. (Outback has an informative web page on this.) You could use a relatively small AGM or LiFePo4 battery, just enough to let the Radian hybrid inverter slosh current back and forth as it keeps up with your loads and turns the microinverters on and off in response to the loads.

It would be interesting if you could split the microinverters into groups that each get their own remote operated breaker so that not all would need to be turned off at once. The Radian has a couple of AUX outputs and could possibly be programmed to use more than one for this. Probably not something that would be supported or terribly practical, though.

If we need to go a DIY route I can hack some other solutions as well. Apparently the Enphase inverters are very good at monitoring phase and voltage of the grid the are connected to, and shutdown very quickly if the specs are not met. You could put an electronic switch between the inverter and the grid to disconnect unneeded inverters. They'll automatically shutdown. I might go that route if things go very wrong and the inverters can be bought rrreally cheap. Maybe. But I'd prefer a proper setup of course, and an Enphase that is nicely in business.

[ButchDeal]

You could use a relatively small AGM or LiFePo4 battery, just enough to let the Radian hybrid inverter slosh current back and forth as it keeps up with your loads and turns the microinverters on and off in response to the loads.

OutBack is very clear about the size of the battery being large enough to handle the full charge from the AC coupled system. A small LiFePo4 is unlikely to handle that.
an AGM might if not too small but the heavy cycling would likely kill it shortly.

[BackwoodsEE]

One possibility would be to AC couple your microinverters to an Outback Radian operating in grid-zero mode. (Outback has an informative web page on this.) You could use a relatively small AGM or LiFePo4 battery, just enough to let the Radian hybrid inverter slosh current back and forth as it keeps up with your loads and turns the microinverters on and off in response to the loads.

It would be interesting if you could split the microinverters into groups that each get their own remote operated breaker so that not all would need to be turned off at once. The Radian has a couple of AUX outputs and could possibly be programmed to use more than one for this. Probably not something that would be supported or terribly practical, though.

[rickj]

sure here you go

Enphase seems to do not terribly well. All the more reason to tell us how to do zero feedback, so we can order some products..

Even if Enphase stops this could be a reassurance that it is still possible to get replacements later:
https://seekingalpha.com/news/327444...ense-agreement

[ButchDeal]

Are you willing to enlighten me?

sure here you go:

https://finance.yahoo.com/quote/ENPH/financials?p=ENPH

https://www.greentechmedia.com/articles/read/Enphase-On-the-Edge-Microinverter-Maker-Lays-Off-11-of-Workforce-and-Plan

https://seekingalpha.com/article/4073230-enphase-energy-financial-trouble

[rickj]

Is there a firmware difference between the (earlier) M250-60 and (later) M250-72 Inverter ?

[FONT=courier new]M250-60.... 4th Generation Inverter
M250-72 ... ?th Generation Inverter ( old 4th Gen or new 5th Gen ? )
I found only one website that stated the M250-72 was 5th Generation.

Enphase datasheet for M250-72 says it's 4th

rick

[rickj]

you seem to have missed the entire financial issue of the product.

Are you willing to enlighten me?

you also seem to be under the impression that the micro inverters last longer than other inverters as well.

Yes, I have that impression, but I know nothing for sure.

rick

[ButchDeal]

you seem to have missed the entire financial issue of the product.
you also seem to be under the impression that the micro inverters last longer than other inverters as well.

[rickj]

why go with enphase since they are not very helpful and in such financial issues?

Expected this remark Well, the product and the idea I like a lot. It's flexible, extendable, the inverters live longer, and there's no single point of failure.

I've always intended to install a pv system, but right now I'm forced to bring a choice forward, as I've installed a swimming pool, and found out the pump uses 1.2kW (9 hours a day)! We still have to decide if we will switch cooking from gas to electric, and what else we'd like to go solar for. So I'd like to start small, and extend much more, later. That is easy with micro-inverters, but not with a line inverter. Those have a limited range of minimum and maximum input and output power.

I also can imagine a company cannot respond to an enquiry of a single prospective private customer that will buy only 20 inverters while they are selling millions elsewhere. I can imagine they are not interested in Europe. I can imagine lots of reasons. A lousy customer relations dept is no reason to slag off a company. (Been there myself.) Actually a solar installer should know, or do the inquiries for me (they now are doing that), and not me, the private customer. It's not an easy question either, I can imagine it takes time till it reaches someone who knows and understands.

It's also that I am stubborn, and don't like to take no for an answer, unless I really understand something I want is not possible. I'm an engineer, I can read data sheets, but Enphase's are just vague enough that I cannot decide whether it will work or not. I'm not alone, given the confusion in this thread

It's also a bit my location and the difficult power company here. Spain is trying to protect the power company's interests with unreasonable measures. They are being told off by the EU, but it'll take time till that is all resolved.

All in all, I haven't given Enphase up, yet. They could learn from this thread, too.

r.

[NEOH]

Is there a firmware difference between the (earlier) M250-60 and (later) M250-72 Inverter ?

M250-60.... 4th Generation Inverter
M250-72 ... ?th Generation Inverter ( old 4th Gen or new 5th Gen ? )
S280 ...... 5th Generation Inverter
IQ 6 ...... 6th Generation Inverter

I found only one website that stated the M250-72 was 5th Generation.

I have not been able to find the Enphase Feature Matrix

2008 - 1st Gen
2009 - 2nd Gen
2011 - 3rd Gen
2013 - 4th Gen
2015 - 5th Gen <- Smart Grid Ready
2016 - 6th Gen <- Smart Grid Ready

I think, but I have no proof yet, that "Zero Export" is a firmware feature since the 5th Generation Inverters