200A Bypass of Sol-Ark and EG4

[Citlalatonac]

Do you think the 200A bypass is overkill? Is 50A enough for now?

Apples and Oranges

200A bypass means you can run a normal 200A panel on the load side of the inverter, without needing to be able to supply 160A of inverter current. Meaning you can charge a car, cool the house, cook a lasagna, dry your clothes, and watch TV all at the same time. While also maintaining the ability to do some of those activities while grid power is down.

50A is the maximum amount of current that can be used to augment the grid power/sell back to grid/run without grid.

 

[zanydroid]

Hot take: 50A is a pretty pernicious number for bypass, because the EPS panel is subject to the general load calculation with respect to how much power needs to be supplied. It is much closer to "add up all the load breakers" than the residential calculation.

If you do 200A bypass you can pass all load calculations from both being eligible for residential calculations and from the higher provisioned capacity. 100A has advantages over 50A as well; I'll leave it as exercise to the reader to derive these.

 

[chicagoandy]

Do you think the 200A bypass is overkill? Is 50A enough for now?

I like the 200A bypass in my Sol-Ark for one reason - the AIO effectively gets placed between the meter and your load panel. The goal of these devices is 'whole home backup'.

Today, most houses are wired for 200a service. If you place an AIO with only a 50 amp passthrough in between your 200a Meter and your 200A panel, you've effectively downgraded your house to 50a. Maybe that's fine for you? But most houses were fit with 200a panels for a reason.

Or you're doing a critical loads panel.

Secondly, you said "is 50A enough for now?" I'll zero in on the "for now". These are expensive devices, if you're buying the 50a one because the 200A one is too expensive, are you really going to upgrade the limited but functioning one that works in the future? Me, I'm too cheap to throw out functioning stuff, so if I did that I'd be stuck with that 50A one forever. For me, better to do it right the first time.

 

[Danke]

Sol-Ark, EG4, etc. with 200A pass-through is nice. But for a similar price you can parallel cheaper 10K or 12K inverters.

For example: 3 Deye 12Ks with yield 180A pass-through AND 36kW of backup power vs 12kW from a Sol-Ark (15k with PV) or EG4. Another bonus of multiple inverters is ability to input more PV and redundancy.

 

[chicagoandy]

Sol-Ark, EG4, etc. with 200A pass-through is nice. But for a similar price you can parallel cheaper 10K or 12K inverters.

For example: 3 Deye 12Ks with yield 180A pass-through AND 36kW of backup power vs 12kW from a Sol-Ark (15k with PV) or EG4. Another bonus of multiple inverters is ability to input more PV and redundancy.

EG4 and SolArk are both US companies, Deye really isn't an option in the USA due to their exclusive deal with Sol-ARk. So the 12K sol-Ark or EG4 is probably a better comparison.

A pair of smaller inverters doesn't really offer redundancy unless you can run effectively off a single one. Real redundancy would be a pair of the full-powered units. That gets expensive.

 

[Danke]

EG4 and SolArk are both US companies, Deye really isn't an option in the USA due to their exclusive deal with Sol-ARk. So the 12K sol-Ark or EG4 is probably a better comparison.

A pair of smaller inverters doesn't really offer redundancy unless you can run effectively off a single one. Real redundancy would be a pair of the full-powered units. That gets expensive.

I said “example”. And there are many, I just used Deye (my current choice).
12K x two, three or four is redundancy vs. one Sol-Ark or EG4. If one Sol-Ark or EG4 fails, you would need a transfer switch as the 200A pass-through would not work. One of three or four other brand 12Ks goes down, you still have over 100A of a Solar system until repaired or replaced. Added bonus: whether grid is available or not.

 

[ohiogators]

Sol-Ark, EG4, etc. with 200A pass-through is nice. But for a similar price you can parallel cheaper 10K or 12K inverters.

For example: 3 Deye 12Ks with yield 180A pass-through AND 36kW of backup power vs 12kW from a Sol-Ark (15k with PV) or EG4. Another bonus of multiple inverters is ability to input more PV and redundancy.

This is what I decided. 126 amps of bypass if good enough for my 200 amp panel.

 

[LesterVolts]

This is what I decided. 126 amps of bypass if good enough for my 200 amp panel.

I took the plunge and am servicing with 200 amp pass through on a sol ark 15 NP with the inverter currently serving as a battery backup with 4 pytes ebox 48100Rs. I plan to have electricians install an ebay sourced 200 amp manual transfer switch in case the inverter takes a shit but for the time being its running things nicely without. This is a 2024 new build home with wood central boiler platinum heat/water and LP backup and uses very little electricity. We have the PV panels on a pallet waiting on install and are maxing out the on board 3 bank MPPTs on the solArk with 16,500 watts. Any more than that as expansion I gather I can expand through the generator connections and Micro inverters for additional strings.
Using Pytes batteries with sol Ark made for an easy inspection in Michigan. I have yet to stress test this system against much more than the central AC and regular home services like a fridge and some lights etc. excited to see if I can come close to net 0 with no sell back or very little draw from grid.

 

[GuyG]

This is called the Microgrid Interconnection Device. You can think of it as integrated in the 18kpv/15K world



It should not. IIRC under NEC A EPS generator only needs to be big enough to supply the largest single load. This dates back to generator backfeed through inlet circuits. Unfortunately I don’t have a code reference for you.


This is somewhat nuanced but the answer is No
even with a separate MID architecture. There is minimal interoperability between inverters in the sense of boosting their AC output. Even within the same manufacturer stacking different models together is fairly rare outside of Enphase and Tesla.

You may think AC coupling of grid tie inverters would work, but across brands you cannot exceed the AC output of your EPS island forming inverter, since that is the only stable power source. You generally cannot stack unmatched island forming storage inverters.

Hmm. I’m not so sure about this. Solark claims that any existing inverter can be AC-coupled with its 15K, either through the gen port or via a load panel, up to a limit of about 19 KW IIRC. Also, if a different brand or model AIO inverter were installed downstream of the SolArk and a grid outage occurred, SolArk would become the grid-forming source for the downstream inverter. At least, this is my understanding.

EG4 has been less clear at times about the AC coupling features of its 18kpv, but I seem to recall someone on this forum hooked up an EG4 6k downstream of an 18kpv with no problems. (Note: I’ve been real busy lately and haven’t kept up with this forum, so maybe EG4 has clarified whether and how it can handle AC coupling).

 

[zanydroid]

Hmm. I’m not so sure about this. Solark claims that any existing inverter can be AC-coupled with its 15K, either through the gen port or via a load panel, up to a limit of about 19 KW IIRC. Also, if a different brand or model AIO inverter were installed downstream of the SolArk and a grid outage occurred, SolArk would become the grid-forming source for the downstream inverter. At least, this is my understanding.

Usually they can grid form for a large variety of GTIs, but the kW-AC rating they can safely manage are limited. Default rule of thumb, unless manufacturer says otherwise, is that the kW-AC of the GTIs must be <= the kW-AC of the grid forming inverter.

Enphase allows a higher ratio with IQ8 and appropriate generation battery. Some folks here have claimed that Victron can exceed 1:1 ratio with Fronius, but I don't see a quick Google confirmation of that (in fact there are a lot of posts that say 1:1 is required, maybe those are outdated)

 

[DIYrich]

Hmm. I’m not so sure about this. Solark claims that any existing inverter can be AC-coupled with its 15K, either through the gen port or via a load panel, up to a limit of about 19 KW IIRC. Also, if a different brand or model AIO inverter were installed downstream of the SolArk and a grid outage occurred, SolArk would become the grid-forming source for the downstream inverter. At least, this is my understanding.

What is your concern about the sol-ark? If the coupled inverter is Ul1791SA compliant, it should work. If not, then the SA can disconnect it from the gen port if it is overproducing. SA recommends NOT connecting to load port because it cannot be disconnected.

 

[GuyG]

What is your concern about the sol-ark? If the coupled inverter is Ul1791SA compliant, it should work. If not, then the SA can disconnect it from the gen port if it is overproducing. SA recommends NOT connecting to load port because it cannot be disconnected.

No concerns. I was questioning Zany’s statement that a SA15k would not be able to utilize the power from another inverter during a grid outage. I agree with you that it should work, either by AC coupling or possibly other means as well.

I do have concerns about whether the EG4 can do so; their vague statements about AC coupling and non-answers on other questions is troubling to me.

 

[zanydroid]

There’s plenty of 18kpv discussions about AC coupling and one or two of the EG4 techs here are pretty specific about answers.

IIRC they also got LuxPower to add AC coupling to 6000XP via firmware update, and that is one segment below