I Can't Afford So-Called "Tier 1" Equipment. What's Good at Tier 2?

[timselectric]

I guess what I’m confused about is that the 6048 is often described as 2-3k units in one box to create split phase.
I’ve also seen it described as LF
Is the 10k y&h/srne the same in that it would be 2-5k units in one box to create a 10k split phase inverter
Which leads to, is that then also how the Growatt 12k is designed?

Or is another way to phrase it, are all LF split phase inverters just two smaller inverters in one box?

In your reply you said “full rated output from each at 120 or together at 240” so in the case of the 6048 would that mean that when people gripe about “load imbalance” is that one leg may have multiple larger 120v items running and the other leg does not, thus creating the imbalance? And then would unbalance not technically be the correct word as there’s really only 3k available to that leg, If so, is that simply a matter of which 120v circuits are connected to which leg? And then with 240 appliances the imbalance issue is irrelevant because it’s pulling from both legs?

Am I understanding this properly?

If so, what then happens with 2 or 3 split phase units in parallel. Does that create more or less imbalance risk

Low frequency inverters are always single inverters.
High frequency split-phase inverters are always two inverters. Either in one enclosure or separate enclosues.
Low frequency means that they use a transformer.
Inverters have their limits. Transformers have their limits. To save costs, both can be value designed. And sometimes rely on each other to boost output.
But rated output is based on all of the individual parts.
The best option for balance is two inverters. Whether high or low frequency. Or a fully rated external transformer.

 

[Hedges]

Low frequency inverters are always single inverters.
...
The best option for balance is two inverters. Whether high or low frequency. Or a fully rated external transformer.

Sunny Island 6048US is 120V, contains transformer something like 30V primary, 120V secondary. (works down to 42V battery input)
I'm contemplating disassembling one, trying to wind 14 awg or 12 awg enamel wire to add a second 120V secondary plus 37V secondary.
That would let me wire it for 120/240V split-phase (with 25A max on the second phase), or 277V.
Look Ma! No external transformers!

 

[42OhmsPA]

Where are you suggesting the transformer be connected?
Unless it is something special, I don't want to connect one to output of an inverter, at rated voltage.
I would run a utility transformer at 50% of rated voltage to avoid the excessive current that comes from partial saturation.
At half of rated voltage, much closer to "ideal" transformer, and about 1/10th as much no-load current draw.

After the inverter before the 120/240vac loads panel.

 

[BuffaloTrace]

@BuffaloTrace let me expand, I “assumed” that by similar model numbers, multiple threads discussing them, both with a weight within 10lbs (and both 20+ lbs heavier than the LV6548) along with 2 links of each model so that if I’m incorrect, I can properly understand as that definitely influences aspects of my own personal system design. Hence my reply to the person telling me I’m mixing them up, seeking clarity. I’ve been trying to digest info non stop so that any “assumptions” won’t cost my pocketbook
I really hope that wasn’t meant to be a snarky reply and that your quote reply was cut off

This may be one of those times as mentioned earlier In the thread related to "banter". Even a bit of banter can shed some light on one's thought process and to help gain some knowledge, maybe even of oneself. I'd hate to see any learned person of this forum make a costly mistake based on bad information. Of course I'm all for experimentation.

 

[42OhmsPA]

One can find these in used options as well.

1-Phase 240x480 - 120/240

This transformer converts either 240V 1-Phase or 480V 1-Phase to 120/240V. This unit is great for lighting, CNC machines, and other business machines.

www.maddoxtransformer.com

What are the advantages of CU over AU?
Those are choices for the winding, correct?

 

[G00SE]

This may be one of those times as mentioned earlier In the thread related to "banter". Even a bit of banter can shed some light on one's thought process and to help gain some knowledge, maybe even of oneself. I'd hate to see any learned person of this forum make a costly mistake based on bad information. Of course I'm all for experimentation.

My apologies, didn’t mean to get short. My heads spinning and I failed to read the room

 

[G00SE]

Thanks Tim for expanding! I think where I fumbled it all was that I thought both 6048s were based on the same type of architecture and completely different from the 6548s
Then I read comments about a 6048 being 2-3k in one which must be referring to the HF version, which I did not know to delineate so then I began assuming that the 6048 was unique in that it was two smaller LF essentially paralleled already in one casing
So I really just threw myself for a whirlwind in the end on false assumptions ?

 

[NCislander]

I'm guessing it would behave the same regardless what is on L2.
I don't feel like testing again, I'm sick of resetting clocks for the day ?

Actually, thats exactly what peeves me the most with taking systems completely offline or testing. All the Clocks all over that need resetting. LoL

 

[BuffaloTrace]

My apologies, didn’t mean to get short. My heads spinning and I failed to read the room

Haha no problem. I wondered the same thing, I knew the LV series was a hf inverter and what I thought was similar to the lv6548, but obviously very wrong. The LV6048 has more in common with the 3048lv-mk and wouldn't be surprised if it's literally just two of those stuck in the same box minus one mppt.

That being said I also saw the old (1 yr+?) Will Prowse lvx6048 tear down video which will shed a lot of light on the internals of what's more of a hybrid inverter it seems.

Ian's youtube of watts247 has a teardown video of the lv6048 where he makes some repairs to a failed unit.

As far as Mppsolar goes the LV6048, LVX6048, and LV6548 are all different machines based on different series.

 

[timselectric]

What are the advantages of CU over AU?
Those are choices for the winding, correct?

Copper or aluminum.
Weight and heat tolerance.

 

[Zwy]

I'm guessing it would behave the same regardless what is on L2.
I don't feel like testing again, I'm sick of resetting clocks for the day ?

Use battery powered clocks.

 

[42OhmsPA]

Use battery powered clocks.

I have one on my wrist and one for my solar weather station, oh and one on my phone.
Edit and one on the inverter ?

 

[Sanwizard]

Saying something is junk because it is not UL listed is a incorrect view of things. There can be a range of quality in the Tier None products. Victron sells some non UL listed components. It however has a good reputation for reliability and engineering standards.

That is true, but your homeowners insurance company may have a say about that, so I think insurability needs to be part of the criteria.
I have both SMA and MPP. The MPP units are UL listed and have WAY more capability, but their documentation, software/firmware is suspect.
The SMA's have been running non-stop with zero issues since 2008, and are still perfect. That right there puts them in Tier 0 status by me. Cost doee not mean better. My neighbor has constant issues with their Sol-Ark(Deye), which cost way more than SMA and MPP.

 

[Hedges]

After the inverter before the 120/240vac loads panel.

In that case, I think wiring a 240/480 primary, 120/240 secondary transformer with 240 || 240 driven by 240V from inverter(s) will draw relatively high no-load current. They are designed cheap, allowed to partially saturate.

The two 240V primary windings in series would make a nice auto-transformer for 120/240V. That will have low idle current, about 1/10th as much (and reduced power handling compared to nameplate.) But using it as isolation transformer, output in series 120/240V windings would only produce 120V.

I would need other windings or a differently wound transformer to get 120/240V split phase out.

Check out my current measurements and waveforms. Secondary 120V driven 120V, primary 240V driven 120V, primary 240V driven 240V.

transformer excitation current - isolation transformer used as auto-transformer

So you think you can backfeed a transformer secondary, either as step-up or as auto-transformer? Turns out these things aren't so ideal and reversible as one might expect. It isn't just the greater inrush (primary is often wound outside secondary to reduce inrush current), but also idle current...

diysolarforum.com

Copper or aluminum.
Weight and heat tolerance.

And efficiency (I think) and price.
Aluminum requires thicker conductors, so current flow is further from core, less coupling. But maybe that's not a bug, it's a feature.
Some of my transformers have multiple windings with about 1/2" gap between layers. Air flow and more leakage inductance. Copper or aluminum would be similar if not packed tightly.

 

[timselectric]

And efficiency (I think) and price.

Absolutely

 

[42OhmsPA]

In that case, I think wiring a 240/480 primary, 120/240 secondary transformer with 240 || 240 driven by 240V from inverter(s) will draw relatively high no-load current. They are designed cheap, allowed to partially saturate.

The two 240V primary windings in series would make a nice auto-transformer for 120/240V. That will have low idle current, about 1/10th as much (and reduced power handling compared to nameplate.) But using it as isolation transformer, output in series 120/240V windings would only produce 120V.

I would need other windings or a differently wound transformer to get 120/240V split phase out.

Check out my current measurements and waveforms. Secondary 120V driven 120V, primary 240V driven 120V, primary 240V driven 240V.

transformer excitation current - isolation transformer used as auto-transformer

So you think you can backfeed a transformer secondary, either as step-up or as auto-transformer? Turns out these things aren't so ideal and reversible as one might expect. It isn't just the greater inrush (primary is often wound outside secondary to reduce inrush current), but also idle current...

diysolarforum.com

You kinda lost me, I need to read it about 6 more times. ?

If I'm understanding, you're saying wiring 230 EU inverters to each primary would work nicely for US 120/240 output?

And efficiency (I think) and price.
Aluminum requires thicker conductors, so current flow is further from core, less coupling. But maybe that's not a bug, it's a feature.
Some of my transformers have multiple windings with about 1/2" gap between layers. Air flow and more leakage inductance. Copper or aluminum would be similar if not packed tightly.

 

[Hedges]

You kinda lost me, I need to read it about 6 more times. ?

If I'm understanding, you're saying wiring 230 EU inverters to each primary would work nicely for US 120/240 output?

I'm still learning about magnetics. It is almost a lost art (some of the more obscure aspects and applications.)
On-grid power transformers are mainstream, but optimized for cost.

Two separate issues. You can use a 230V inverter with isolation transformer to create 120/240V split phase. That derives a new neutral, which you bond to ground.
You can just as well stack two 120V inverters in series (or use a split-phase inverter) and connect such a transformer so 100% of inverter power is available on either 120V phase or 240V phase.

Second issue is that real transformers you purchase aren't like the idea or near-ideal ones you may have studied.
We expect, with sine wave voltage applied, to get a small sine wave current under no-load (shifted +90 degrees because it is an inductor).

What I find is relatively high current, like 4A (480VA for a 240V input), under no load.
The current looks more like a Hersey's kiss than a sine wave. That is something called "saturation", the no-load current is enough to almost make the iron core stop working, and current shoots up high.

A transformer optimized for this application (maybe twice as big) would behave nicely. You should be able to find and buy one, if you try hard enough and understand the specs.

What I've done is to operate transformers well below their rated voltage. They are much closer to ideal that way. Like draw maybe 0.6A instead of 4.0A, and make a rounded curve on the oscilloscope.

 

[42OhmsPA]

Thank you @Hedges I'm going to do some more homework on the neutral and grounding as well as understanding what can happen if a fault would occur.

If I went this route I would definitely oversize.

 

[BuffaloTrace]

This sounds like an even more modular route, and totally different direction than the point of an AIO. And of course totally not against it. I think it's fascinating all the options.

 

[42OhmsPA]

My thinking is you are still gaining the features of an aio but utilizing the transformer to optimize, I also think the single phase units will be more robust since the countries that use them have been into renewable energy long before it took off in the US.

 

[timselectric]

That was my plan.
Affordable, reliable, and redundancy.

 

[Zwy]

I've been watching. It looks like they may have solved the feeding back to grid issue with a firmware update. We'll see. I'm pretty sure I'm not doing anything until this fall at the earliest, and maybe next spring. If it's the 18kpv I want to see some more track record. If it's something else - well, I haven't found a something else yet that really gets me fired up. Who knows, it may end up being four of the SCCs. I feel fortunate that I'm in a place where my system works well enough that I can wait.

You should purchase one, they might have a slightly used one coming in. https://diysolarforum.com/threads/t...eturning-and-replaced-with-sol-ark-15k.66786/

History repeats itself: https://diysolarforum.com/threads/i...ipment-whats-good-at-tier-2.65062/post-817667

I lost 100 hours plus working for Signature Solar for free. 100 hours I could have spent fishing, drinking, quality time with The Official Loads Tester, cruising, traveling.............

I like the EG4 MPPT100-48HV but I don't think I'd purchase another inverter there unless it has a very long track record. I doubt that will happen, when this blows up they will move on to another OE manufacturer.