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timselectric said:

What i said was "Transformers are used in every system all over the world. A Transformer is how you have split-phase in your house right now"

I should have said "Transformers are used in every >grid< system all over the world. A Transformer is how you have split-phase in your house right now"

The point being that transformers are used widely.
In my 38 years in the trade, I have installed more than a couple hundred. The only thing that makes the SPF-5000-ES different between the US and European version, is the bonding to ground. If that doesn't exist, it's compatible with any system in the world.

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Yes..again I understand my poco uses a transformer to provide the neutral to me for split phase. I thought you were saying HF uses transformers to provide split phase which is why I was asking for clarification as I thought perhaps I misunderstood them or the vendor was lying in saying they didn't have a transformer. Thanks for the update.

BenFromSignatureSolar said:

In a mobile application the N/G bond will take place in the main load panel much like an off grid app.

The Mid-point transformer is UL 1741 compliant. Intertek was the testing facility. However, I do not have a schematic available to share here.

Apologies if that leaves some of your questions unanswered. But that's the info that I have available to share.

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Wouldn't a valid solution provide professional documentation vetted by the vendor or qualified 3rd party? It would behoove all parties involved if there was proper wiring diagrams and the caveats regarding the different ways to wire this solution both on grid, off grid, mobile etc. Also, if a generator is used does it provide the N/G bond etc? If you're going to provide videos, which are not proper forms of documentation, then you should provide videos in different usage scenarios as mentioned above; then show us if voltage is going over the ground wire in each case usage etc. There was a gentlemen on youtube, albeit using mpp with the grounding screw removed, that had things bonded at the main panel as he should. When the inverter was using the grid it was fine but he found out when the grid was off and he was inverting he had significant voltage on the ground wire. I'm not sure what he did or if he resolved it as there was no updates.

BenFromSignatureSolar said:

In a mobile application the N/G bond will take place in the main load panel much like an off grid app.

The Mid-point transformer is UL 1741 compliant. Intertek was the testing facility. However, I do not have a schematic available to share here.

Apologies if that leaves some of your questions unanswered. But that's the info that I have available to share.

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UL Listed or not, I don't believe the transformer/breaker/switch SS is selling can be used in an NEC compliant manner with split-phase utility grid input.

If both inputs were floating (inverter, generator, 240V isolation transformer fed from grid), and if instructions directed bonding neutral to ground, then I think it would be NEC compliant.

The following table table from your "manual" says the transformer/ATS can be used for 240V or 208V



The following diagram shows the transformer configuration which produces 120/208Y.
208V is the voltage between any two lines, e.g. L1 and L2.
Your transformer will form a "neutral" half way between L1 and L2 that is anything but neutral.
What is labeled as "N" in the manual's diagram is anything but neutral, for such an application.
It will be 60 Vrms.
Each "line" will be 104Vrms.
(both of those while fed from L1 & L2 of a 120/208V grid; after transferring to your inverter it would be 120/240V split-phase, but floating without neutral/ground bond.)




I only see some NEC compliant ways to use this transformer/ATS, and then with instructions beyond what you have published.

Since we're on this subject is there a reason watts or SS can't work to either import these as split phase or offer them like they are the growatt with a inverter? Why can't we seem to get past the 6KW on the mpp here in the US? How about a new EG4 inverters @ 12kw? And ..at least a 100A pass through while 200A would be ideal.

Two 120V HF inverters (either in two boxes or one) is the low-cost light weight solution to providing 120/240V split-phase.
That saves the cost of aluminum or copper low-frequency windings and the weight of iron core.

Hey @BenFromSignatureSolar, do you offer such a product?
I think that is what you should have for price-sensitive customers.

You do have LF split-phase:


And it looks like 120V HF single-phase, stackable for 120/240V split-phase:


A pair of those would be $1438, 3kW on either 120V output, 6kW at 240V.

I think that's what you should be promoting rather than auto-transformer on output of 240V inverter (for customers with grid input.)
Oh, does that have relay to feed through from grid? Or just a battery charger?

Hedges said:

Two 120V HF inverters (either in two boxes or one) is the low-cost light weight solution to providing 120/240V split-phase.
That saves the cost of aluminum or copper low-frequency windings and the weight of iron core.

Hey @BenFromSignatureSolar, do you offer such a product?
I think that is what you should have for price-sensitive customers.

You do have LF split-phase:

Growatt 12KW Split Phase Off Grid Inverter | SPF 12000KT DVM-US MPV

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

And it looks like 120V HF single-phase, stackable for 120/240V split-phase:

https://signaturesolar.com/content/documents/GROWATT/1519009-specs.pdf

A pair of those would be $1438, 3kW on either 120V output, 6kW at 240V.

I think that's what you should be promoting rather than auto-transformer on output of 240V inverter (for customers with grid input.)
Oh, does that have relay to feed through from grid? Or just a battery charger?

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I mean really if someone was to go that route, we would recommend the EG4 6500. It would be a couple hundred more dollars but the communication with our batteries will be much better. (Well except for the V2 LL battery that came out today. It communicates with Growatt, EG4, Schnieder, Victron, Sol-Ark, and one or two others)

The specs on the 6500 are huge as far as MPPT input goes. That would probably be in line with what you were mentioning.

BenFromSignatureSolar said:

I mean really if someone was to go that route, we would recommend the EG4 6500. It would be a couple hundred more dollars but the communication with our batteries will be much better. (Well except for the V2 LL battery that came out today. It communicates with Growatt, EG4, Schnieder, Victron, Sol-Ark, and one or two others)

The specs on the 6500 are huge as far as MPPT input goes. That would probably be in line with what you were mentioning.

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We'd like to see EG4 at 12/15k output though...just because it's a lower tier inverter doesn't mean they can't keep up.

But..all these MPP clones though are basically the same...meh. MPP does not seem to be interested in upping their game regarding build quality; they seem to have no planes for targeting a higher tier product like deye for example. While I'd defiantly be interested in a EG4 at a much higher wattage output I'd also be enthusiastic if somebody decided to compete with solark at a much more realistic price point. Either work with MPP to up their game and build a much higher quality inverter or give deye a jingle and work with them to build a inverter for you. Personally, I think SS or watts etc.. could figure out a way to import deye inverters and use the anti trust laws against solark. Put it in a different case, paint it a different color and slap a different logo on it...that's what everybody else is doing. While they wont ship to the states you can find a 16k deye on chinababa for $2500. There's got to be a way to get this in our hands split phase hopefully...and keep that price point.

realpinochet said:

We'd like to see EG4 at 12/15k output though...just because it's a lower tier inverter doesn't mean they can't keep up.

But..all these MPP clones though are basically the same...meh. MPP does not seem to be interested in upping their game regarding build quality; they seem to have no planes for targeting a higher tier product like deye for example. While I'd defiantly be interested in a EG4 at a much higher wattage output I'd also be enthusiastic if somebody decided to compete with solark at a much more realistic price point. Either work with MPP to up their game and build a much higher quality inverter or give deye a jingle and work with them to build a inverter for you. Personally, I think SS or watts etc.. could figure out a way to import deye inverters and use the anti trust laws against solark. Put it in a different case, paint it a different color and slap a different logo on it...that's what everybody else is doing. While they wont ship to the states you can find a 16k deye on chinababa for $2500. There's got to be a way to get this in our hands split phase hopefully...and keep that price point.

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The need has been noticed and calculated. There are currently many irons in the fire at SS.

BenFromSignatureSolar said:

The need has been noticed and calculated. There are currently many irons in the fire at SS.

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Just don't leave them too long and let them melt.

BenFromSignatureSolar said:

I mean really if someone was to go that route, we would recommend the EG4 6500. It would be a couple hundred more dollars but the communication with our batteries will be much better. (Well except for the V2 LL battery that came out today. It communicates with Growatt, EG4, Schnieder, Victron, Sol-Ark, and one or two others)

The specs on the 6500 are huge as far as MPPT input goes. That would probably be in line with what you were mentioning.

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6500W 120V, $1250 each, up to 6x wired split-phase or 3 phase.
No transformer needed. Much better than trying to use a 220V inverter and autotransformer in a grid-backup system.
At 40 lbs. each, 4x of these (HF) inverters have (continuous and surge) power slightly above my 4x Sunny Island, but weigh (and cost) barely more than one

realpinochet said:

While they wont ship to the states you can find a 16k deye on chinababa for $2500. There's got to be a way to get this in our hands split phase hopefully...and keep that price point.

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Looks like 2x EG4 6.5kW comes close. 13kW (26kW 5 second surge) for $2500.
Feature set probably differs (especially grid feeding and supporting AC coupling), but for some applications would do the same things.

Hedges said:

Looks like 2x EG4 6.5kW comes close. 13kW (26kW 5 second surge) for $2500.
Feature set probably differs (especially grid feeding and supporting AC coupling), but for some applications would do the same things.

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The quality of the internals and overall build quality is much higher on the deye....the solarks proved this out over time which is why I hope somebody can figure out how to get deye in the USA again. This is just my personal opinions from research and talking to others. Solark is way overrated, they are still a great inverter but overrated and way overpriced. They are not a tier 1 inverter. Tier 1 would be schneider, outback, sma etc. Mpp and growatt are tier 3 inverters. Deye seems to be a fit for a solid tier2 inverter where a gap exist in this field. Solark could have fulfilled this need but they decided to be greedy and charge four times what the inverter is worth. Deye 16k split phase with 200 amp pass through at $2500 would crush it in the diy community for us that are on a budget but still seek quality and long term durability. I'd love to have 4x sma inverters like you...maybe one day.

A couple of new sellers with Sunny Islands on eBay. "New" as in zero feedback.
But the $2500 price and eBay for protection could be attractive.
By the time you buy two and add everything else (including SCC or GT PV) to make a split-phase system, it'll still be way over that $2500 Deye price.
I stopped counting the cost long ago.

If youre off grid why would you ever want split phase ?

.

775 said:

Maybe charge an EV? Run a dryer?

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Why not simply generate 240vac single phase. From the appliance perspective it’s the same

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Goboatingnow said:

Why not simply generate 240vac single phase. From the appliance perspective it’s the same

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Connect 240VAC to your 120VAC vacuum cleaner and see how much it likes it ?

You would want 120V for typical loads.
Heating loads and larger motors can be 240V (of 120/240V split-phase) or 208 (of 120/208Y.)
If you buy three inverters then you can have the 3-phase, good for some shop tools.
I think you can generate 3-phase from two inverters which are 120 degrees apart, by using transformers. But a third inverter may cost less.

Or maybe running them with VFD is better. You get variable speed and soft start.
But cheap VFD, due to diode/capacitor front end, has bad power factor and creates harmonics. That upsets some of my inverters (AC coupled Sunny Boy) but hasn't been a problem for Sunny Island battery inverters.

775 said:

You still have to convert to 120v for the other stuff in the house right? Do you mean it would be cheaper/efficient to just run 240v from the start and then transform it down to what's needed?

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If you've got a transformer, this would let all watts of your 240V inverter supply single-phase 120V. Compare to two stacked inverters, each phase gets the power of just one inverter. Transformers do have a standby load. For instance, here are no-load voltage and current traces for a 9kVA toroid transformer. With 118Vrms applied it carried 0.67Arms, for 67W reactive power. That's mostly energy stored in the inductance (out of phase current), and how much is recovered by the inverter vs. dissipated somewhere would make a big difference in battery life. I'll have to check that some day, wanted to use this transformer to let slave inverters sleep, only operate master, to save power under low load.

SparkyJJO said:

Connect 240VAC to your 120VAC vacuum cleaner and see how much it likes it ?

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It should really suck!

(universal motor spins faster with more voltage. Maybe not for long? Low-rider guys would put 72V into 12V hydraulic pumps.)
I think I did plug a floor sander into repair shop test outlet while it was set to 240V, and it smoked from the get-go. So there are limits.

SparkyJJO said:

Connect 240VAC to your 120VAC vacuum cleaner and see how much it likes it ?

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Do the same with L1 and L2 of split phase and report back