Currently have Enphase, looking for total off-grid solution (EG4 6000XP)

[banquo]

This is more paranoia than anything but I would like a system that doesn't have an internet-connected controller. I currently have an Enphase solar/battery system installed. The idea would be in a civic emergency where the grid here in SoCal was shutdown and let's assume Enphase was "ordered" to shut down customer DER's via the controller, I wanted to be able to bypass the Enphase system entirely (micro-inverters, Controller, batteries) and go Solar Panel to "alternate" Solar Charge Controller directly. For this I assume I would need to re-wire the panels, in a serial fashion, to a new Solar Charge Controller to which I can add (non-Enphase) batteries later.

I saw Will Prowse's review of the 120/240 EG4 6000XP and like that option for the price ~$1400. I would need some MC4 cable (est ~$300). I would have to re-organize a few panels. Our current (19) JA-Solar panels are rated 355W (38.5Vmp) with a max output in peak summer ~305W (they are 6 years old). This Eg4 can take 4000W (480VDC) per leg times two legs - 8KW total - more than enough. I figure I can string 10 panels in one leg and 9 panels on the other (total 19 panels) and still meet the 120VDC minimum to fire up the controller and be well under the limit of 480VDC/leg.

Assuming all that seems ok to you so far, I am looking at purchasing the MC4 cables and am confused on the sizing and length guidelines. If I string these serially, the current should stay the same, rated Imp 9.16A/string. So the off-the-shelf MC4 25' extension cables should handle this load, less than 10A each leg? I am guessing that the total length of each string needs to be added to the 25' MC4 extender length when calculating max current each string can handle?

If I am missing something, please advise. If this ~$2K "emergency prepper" proposed backup to the current Enphase system will work, then I need to decide if it is worth the cost. Trying to vet the solution here first.

Thanks in advance

 

[Zapper77]

This is more paranoia than anything but I would like a system that doesn't have an internet-connected controller. I currently have an Enphase solar/battery system installed. The idea would be in a civic emergency where the grid here in SoCal was shutdown and let's assume Enphase was "ordered" to shut down customer DER's via the controller, I wanted to be able to bypass the Enphase system entirely (micro-inverters, Controller, batteries) and go Solar Panel to "alternate" Solar Charge Controller directly. For this I assume I would need to re-wire the panels, in a serial fashion, to a new Solar Charge Controller to which I can add (non-Enphase) batteries later.

I saw Will Prowse's review of the 120/240 EG4 6000XP and like that option for the price ~$1400. I would need some MC4 cable (est ~$300). I would have to re-organize a few panels. Our current (19) JA-Solar panels are rated 355W (38.5Vmp) with a max output in peak summer ~305W (they are 6 years old). This Eg4 can take 4000W (480VDC) per leg times two legs - 8KW total - more than enough. I figure I can string 10 panels in one leg and 9 panels on the other (total 19 panels) and still meet the 120VDC minimum to fire up the controller and be well under the limit of 480VDC/leg.

Assuming all that seems ok to you so far, I am looking at purchasing the MC4 cables and am confused on the sizing and length guidelines. If I string these serially, the current should stay the same, rated Imp 9.16A/string. So the off-the-shelf MC4 25' extension cables should handle this load, less than 10A each leg? I am guessing that the total length of each string needs to be added to the 25' MC4 extender length when calculating max current each string can handle?

If I am missing something, please advise. If this ~$2K "emergency prepper" proposed backup to the current Enphase system will work, then I need to decide if it is worth the cost. Trying to vet the solution here first.

Thanks in advance

I used 10awg, not sure why but it might have been a requirement for my electric code.

 

[banquo]

I used 10awg, not sure why but it might have been a requirement for my electric code.

Yes, makes sense. I didn't want to make my own custom cables. I believe the off-the shelf MC4 cables are 10AWG. I should get up to 30A @100 feet with that (assuming the connectors handle 30A)

 

[Ampster]

If I am missing something, please advise.

Whether or not Enphase is "ordered" to shut down or it does it because the grid has failed results in the same loss of generation. To implement the system the OP proposes would reguire rewiring every panel and disconnecting each one from their individual micros. If the system is ground mount that might be more practical than a system on a roof. An alternative, which I use is a hybrid inverter which AC couples to the Enphase when the grid is down to emulate the grid hyand cause the Enphase ro power up. The cost of a reliable hybrid inverter with batteries which can do that is not cheap but works for me seamlessly without requiring me to go up on the roof and rewire everything. The concept is called AC coupling. It allows me to use the grid as a backup and then power my house from the AC coupled Enphase micro when the the grid is down. My answer is irrelevant if the OP wants to be entirely off grid all the time instead of having a backup system when the grid goes down.
EDIT:
After rereading this thread I realized the OP already has Enphase batteries and the above advice is irrelevant.

 

[banquo]

Whether or not Enphase is "ordered" to shut down or it does it because the grid has failed results in the same loss of generation. To implement the system the OP proposes would reguire rewiring every panel and disconnecting each one from their individual micros. If the system is ground mount that might be more practical than a system on a roof. An alternative, which I use is a hybrid inverter which AC couples to the Enphase when the grid is down to emulate the grid hyand cause the Enphase ro power up. The cost of a reliable hybrid inverter with batteries which can do that is not cheap but works for me seamlessly without requiring me to go up on the roof and rewire everything. The concept is called AC coupling. It allows me to use the grid as a backup and then power my house from the AC coupled Enphase micro when the the grid is down. My answer is irrelevant if the OP wants to be entirely off grid all the time instead of having a backup system when the grid goes down.

Thank you for the follow up. I am guessing the SolArk is your recommended Hybrid inverter? That would be too cost prohibitive for me (at least the 12K model). My Array is 6.7KW. While I like the idea of having something that is integrated and doesn't require rewire, I'm not sure how I would get around all of my microinverters potentially being "decommissioned" by the cloud. The $1400 price on this EG4 was the trigger to have a backup emergency solution. I certainly do not like the idea or having to rewire it all, I am guessing there is at last 90 minutes of work there - I would only do this in the event of my Enphase system going 100% dark based on logical controls (hack, natural disaster, or civil unrest). So a workable low cost solution due to low implementation probability is the key

 

[zanydroid]

I don't understand the scenario here. The only one I can think of is if someone hacks the Enphase cloud. Why don't you just pull the 4G backhaul radio then in the controller and unhook all WiFi/wired Ethernet? Maybe pre-emptively. You can pull the card/cables Saturday morning and verify that it still works on-grid and when grid is disconnected.

Without a battery you'll have very unreliable power, and you will need to either forgo RSD or set up a dark start runbook with a small starter battery, and execute this every morning / after a particularly dark storm cloud. I guess in this SHTF situation nobody's going to police your lack of RSD. In a situation as dire as this, where are you going to reactively buy a battery? You'll probably need to hoard some barter goods or gold ?

You mean need to leave a WiFi connection open on the inverter to configure it, so need to have a game plan for locking that down, or accepting that threat vector. Or, pick an inverter that has wired Ethernet connectivity module and put it on an air-gapped management network.

The concept is called AC coupling. It allows me to use the grid as a backup and then power my house from the AC coupled Enphase micro when the the grid is down. My answer is irrelevant if the OP wants to be entirely off grid all the time instead of having a backup system when the grid goes down.

Why discuss a new hybrid AC coupling system when OP already has IQ Batteries installed? Which are AC coupled batteries.

 

[zanydroid]

Yes, makes sense. I didn't want to make my own custom cables. I believe the off-the shelf MC4 cables are 10AWG. I should get up to 30A @100 feet with that (assuming the connectors handle 30A)

You can probably connect the panels in series with existing cables on the solar panels.

I would not trust off-the-shelf cables off Amazon, you would maybe get them custom made with the correct MC4 connectors from a reputable supply house.

Making MC4 cables is barely an inconvenience, you just need a $40 crimp tool. I would prefer to do this with the home run, while any jumpers I need I can have them custom made. Also for prepping mindset you should really be willing to have this tier of maintenance tool...

 

[Quattrohead]

Disconnect the enphase system from your network or remove their cell based communication module and AC couple them to the EG4.
Best of both worlds and little rewiring needed.

 

[zanydroid]

and DC couple them to the EG4

You mean AC couple? I thought 6000XP didn’t support that yet.

Also I’m not sure what the 6000XP is serving if no battery purchased for it, and the IQ Batteries are already installed. And the 6000XP probably makes things more complicated since both it and Enphase may insist on grid forming

 

[Ampster]

Why discuss a new hybrid AC coupling system when OP already has IQ Batteries installed?

I reread the original post and now realize that.

 

[Shimmy]

You are really over-complicating things to the point of an irrational strategy. First off, re-wiring in an emergency will be a struggle. Second, the EG4-6000XP is likely the wrong inverter for your goals, but you need to look at your needs first.

For your specific area you might be better off with a 120V hand truck build as a starting point, unless air conditioning is a priority. Beyond that you are looking at ripping out all the Enphase gear which is a lot of cash to burn.

 

[Quattrohead]

You mean AC couple? I thought 6000XP didn’t support that yet.

You are correct, I changed my post. Also I don't know if that feature is supported yet.

 

[Quattrohead]

I reread the original post and now realize that.

I missed that too because I don't associate enphase with batteries.

 

[banquo]

You can probably connect the panels in series with existing cables on the solar panels.

I would not trust off-the-shelf cables off Amazon, you would maybe get them custom made with the correct MC4 connectors from a reputable supply house.

Making MC4 cables is barely an inconvenience, you just need a $40 crimp tool. I would prefer to do this with the home run, while any jumpers I need I can have them custom made. Also for prepping mindset you should really be willing to have this tier of maintenance tool...

I agree with Amazon (Chinese-made) items like these and didn't look there. I priced these from a couple of Solar warehouses ~$300 for five 25' pre-made MC4 M/F-paired cables. The wire and connectors are rated 30A.

 

[banquo]

You are really over-complicating things to the point of an irrational strategy. First off, re-wiring in an emergency will be a struggle. Second, the EG4-6000XP is likely the wrong inverter for your goals, but you need to look at your needs first.

For your specific area you might be better off with a 120V hand truck build as a starting point, unless air conditioning is a priority. Beyond that you are looking at ripping out all the Enphase gear which is a lot of cash to burn.

I have seen YT videos on this and Liked the idea but this is just the inverter and a battery right? I know there is a Solar input(s) but the problem remains in my scenario - to bypass the microinverters. as far as the re-wiring, I estimate it would take me under 2 hours to reconfigure the panels to serial connections and the MC4 add-on cable jumpers to the ne Inverter.

 

[banquo]

Disconnect the enphase system from your network or remove their cell based communication module and AC couple them to the EG4.
Best of both worlds and little rewiring needed.

Yes, that is my goal. My concern is that the Enphase system would already be "decommissioned" with non-working microinverters. As I mentioned, it's a long shot but I am looking to switch quickly from an AC-coupled Enphase Solar/Battery scenario to a total off-grid solution leveraging my existing panels only, with some added MC4 cabling. I can add the EG4 batteries later if needed. I do have a Honda EU7K which will work with this Eg4 Inverter as well.

 

[Quattrohead]

Is your system bought and paid for or are you "renting" it because if so it is not yours to tamper with and they will see the production disappear and will want to know what's happening.

 

[banquo]

I don't understand the scenario here. The only one I can think of is if someone hacks the Enphase cloud. Why don't you just pull the 4G backhaul radio then in the controller and unhook all WiFi/wired Ethernet? Maybe pre-emptively. You can pull the card/cables Saturday morning and verify that it still works on-grid and when grid is disconnected.

Without a battery you'll have very unreliable power, and you will need to either forgo RSD or set up a dark start runbook with a small starter battery, and execute this every morning / after a particularly dark storm cloud. I guess in this SHTF situation nobody's going to police your lack of RSD. In a situation as dire as this, where are you going to reactively buy a battery? You'll probably need to hoard some barter goods or gold ?

You mean need to leave a WiFi connection open on the inverter to configure it, so need to have a game plan for locking that down, or accepting that threat vector. Or, pick an inverter that has wired Ethernet connectivity module and put it on an air-gapped management network.

Why discuss a new hybrid AC coupling system when OP already has IQ Batteries installed? Which are AC coupled batteries.

Yes I can disconnect completely from all Comms but that would be after the damage was done. Maybe it's too fantastical to imaging any actor, good or bad, decommissioning the system, but that is the main driver here. As I mentioned first off, it's highly improbable, bordering paranoia. I just want the valid option for a "quick-change" for my panels from AC coupled to off-grid.

 

[banquo]

Is your system bought and paid for or are you "renting" it because if so it is not yours to tamper with and they will see the production disappear and will want to know what's happening.

No, I own it. I installed and commissioned it.

 

[zanydroid]

Yes I can disconnect completely from all Comms but that would be after the damage was done. Maybe it's too fantastical to imaging any actor, good or bad, decommissioning the system, but that is the main driver here. As I mentioned first off, it's highly improbable, bordering paranoia. I just want the valid option for a "quick-change" for my panels from AC coupled to off-grid.

I meant disconnect it beforehand. You don’t need the comms to operate. There may be a comms requirement for warranty however.

You are also assuming that the microinverters will be bricked. I think the most likely worst case is they’re forced to a bad grid profile and not able to turn on.