*Big* inverters? Are these not a thing?

[JaimeZX]

Hi all! So I'm planning a ~21kw ground array and looking at some of the new Trina 650-700W panels, (Imp ~18.5A) and I have a question... (Availability & delivery issues aside!)

Where do you get suitable MPPT/inverters for these things?

Originally I was looking at Victron but they all seem to have max solar input currents of around 13A. I see some EG4s with 18V input currents (Ex: EG4 6000XP), which I guess should be okay... the 620W Trinas put out 15A so the EG4s should be good enough there...

But even then, if I use the Victron "what do I need?" website and pick more "normal" 420W panels, I can only put 3-5 in a string before they don't have any recommended products.

So...
Q1: Am I missing something? I know at least some of y'all have 20kw+ arrays, is there a reason why I can't find an MPPT with that kind of input current?

RELATED: So if I look at the EG4 6000XP as the "biggest" MPPT I can find, the relevant info seems to be
Max usable input current - 17A... MPPT Operating range 120-385VDC ... Nominal MPPT Voltage 320VDC ... Maximum utilized solar power 8000W. (4000W per MPPT).
So (with the 620W panels @ 15A x 41.4V ) that would be two strings of 6 (3726W x2 = 7452W). Or with 445W panels (15.1A x 29.5V), two strings of 9 for 8010W total.

Q2: Both of the above examples math out to well under 320VDC (6 x 41.4 = 248.4V) & (9 x 29.5 = 265.5V). Am I better served by finding panels that will string out to get me as close to 320V as possible? (Or, finding an inverter with nominal ~250VDC operating?) Or is that not a big deal?

Q3: The next question becomes "huge buck converter time." Because if the ground array is going to be some distance from the house then I'll want to push the voltage as high as possible to minimize line losses... Both of the Trina panels have max voltages of 1500, so in theory I could put all 33 of the 620W panels in series for 1242VDC before the underground run to the house... but then I need to drop it to ~450VDC safely somehow. Guess I could put three inverters in parallel but if one shuts down for some reason the other two would spike to over 600V, pesumably not good.

Thoughts on this, anyone? I'd be most grateful.

 

[green mountain boys]

As for a Victron inverter, Take a look at the MPPT RS 450/100 or MPPT RS 450/200. It might be suitable.

 

[robbob2112]

You step up to the Victron 450/200 or a schneider 100 600, or some of the other isolated type MPPTs. Also a lot of the AIO systems have higher voltage ranges

 

[MattiFin]

What sort of inverter you are looking for?

Grid-tie, offgrid, hybrid?

Sky is the limit on grid tie inverters, easy to find 50kW models and sizes go up to several hundred kW per unit

 

[MattiFin]

Sungrow SG250HX-V112 Multi-MPPT String Inverter for 1500 Vdc System

Sungrow SG250HX-V112 Multi-MPPT String Inverter for 1500 Vdc System

www.europe-solarstore.com

250kW with 1500V dc inputs. Need more?

 

[ricardocello]

If the Isc is less than 20A,
and it is I believe on these Trinas (18.3A)

Trina Solar Panels 680Watt 690Watt 700 Watt Bifacial Mono Largest Solar Panel - JMHPOWER

Features High customer value. The star of LCOE (Levelized Cost Of Energy). Higher string power feature effectively reduces BOS (Balance of System) and LCOE.. More energy harvest with cutting-edge N-typei-TOPCon technology,. Designed for compatibility with existing mainstreamsystem components...

jmhpower.com

then the Victron RS 450/200 can give you 4x up to 8s strings (9s is too close to the 450V max Voc).
However, each tracker is limited to 4000W, and the total battery DC power is limited to 11.5 kW.
Ridiculously, this would be over paneled by 94%. Don't do that, too much.

So, buy either 16 or maybe 20 of these panels for a single RS 450/200. (4s or 5s per MPPT tracker).
There's lots of tradeoffs.

https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-MPPT-RS-EN-.pdf

The max MPPT current is 18A, and the panels I linked to have Imp of 17.3A, so that's good.
If you are looking at even beefier panels from Trina, the RS 450/200 may not cover it.

 

[Quattrohead]

12000xp has the highest power mppt's that I know of in the EG4 range, but of course there's only two of them as opposed to three of them in the flexboss.
If you need permits and inspections you'll be looking at a flexboss but if you don't you can look at the 12000xp.

 

[NC_hydro]

You'll find bigger wattage panels isn't always better.

 

[Brucey]

Hi all! So I'm planning a ~21kw ground array and looking at some of the new Trina 650-700W panels, (Imp ~18.5A) and I have a question... (Availability & delivery issues aside!)

Where do you get suitable MPPT/inverters for these things?

Consider one or two midnite Barcelona sccs (200A and dual trackers, 30A pv limit). 585V effective max voltage. Made in Arlington, WA.

The 450/100 and 200 may not be available for a couple months while they redesign them.

 

[JaimeZX]

Thanks, all, for the robust responses so far! Lots of things in here I hadn't heard of before; very helpful.

What sort of inverter you are looking for? Grid-tie, offgrid, hybrid?

Off-grid. The power company gave me an estimate of $15,000-$18,000 to run a line from the nearest pole, so that gets me a *lot* of solar for a similar price.

Take a look at the MPPT RS 450/100 or MPPT RS 450/200. It might be suitable.

You step up to the Victron 450/200

Yes, I appreciate that direction - they have so many products I haven't waded through all the data sheets yet, but those do say 18A input.

schneider 100 600, or some of the other isolated type MPPTs. Also a lot of the AIO systems have higher voltage ranges

250kW with 1500V dc inputs. Need more?

midnite Barcelona

Thank you for the additional suggestions! I'll definitely look closely at those as this whole project comes into focus.

12000xp has the highest power mppt's that I know of in the EG4 range, but of course there's only two of them as opposed to three of them in the flexboss.
If you need permits and inspections you'll be looking at a flexboss but if you don't you can look at the 12000xp.

I assume I'll need permits and inspection. There is a form on the county website for solar approval; I assume this applies to on- and off-grid setups but I've been too busy at work the last couple of days to call them and confirm that. Since an electrical inspection will be required for the house I assume the solar would be part of it.

You'll find bigger wattage panels isn't always better.

Open to suggestions! From Reddit, I gather most peoples' challenges with the bigger panels is... they're bigger. And more challenging to wrestle. I figure this is less of an issue with a big ground array and plenty of room to work, but I'm open to being convinced otherwise.

 

[HighTechLab]

Off-grid. The power company gave me an estimate of $15,000-$18,000 to run a line from the nearest pole, so that gets me a *lot* of solar for a similar price.

I can tell you from experience, that is not a bad price. My parents got a quote was $70,000 and honestly, they should have done it and supplemented/offset with solar. We aren't far from being equal in cost after all of the learning mistakes. In their older age, they can't keep up on maintenance and they have nothing to fall back on if the equipment fails. Their generator was stolen from their well a few months back and were left scrambling to Harbor Freight to keep the water running.

I guess this makes me an outcast here on the DIY solar forum - but I'm just trying to say, be smart and don't try to be pennywise and dollarfoolish. Upfront costs aren't always everything.

Annnnd I'd go with smaller panels, 400ish watts. They are still man-handlable and the equipment can also handle their specs. The super large panels can be left for solar fields where they are running 1500V strings.

 

[JaimeZX]

I can tell you from experience, that is not a bad price. My parents got a quote was $70,000 and honestly, they should have done it and supplemented/offset with solar. We aren't far from being equal in cost after all of the learning mistakes. In their older age, they can't keep up on maintenance and they have nothing to fall back on if the equipment fails. Their generator was stolen from their well a few months back and were left scrambling to Harbor Freight to keep the water running.

I guess this makes me an outcast here on the DIY solar forum - but I'm just trying to say, be smart and don't try to be pennywise and dollarfoolish. Upfront costs aren't always everything.

Annnnd I'd go with smaller panels, 400ish watts. They are still man-handlable and the equipment can also handle their specs. The super large panels can be left for solar fields where they are running 1500V strings.

No I appreciate all that feedback. I definitely expect a fully off-grid setup to cost more than the $18k... But if I pay $18k to connect to the grid, my motivation for then spending another $20k+ on a solar setup is going to be... dramatically reduced. Still investigating many options here.

Thank you for taking the time to write up your reply.

 

[JaimeZX]

In their older age, they can't keep up on maintenance and they have nothing to fall back on if the equipment fails. Their generator was stolen from their well a few months back and were left scrambling to Harbor Freight to keep the water running.

Actually this was rattling around in my head all evening and you make an interesting point... I had sort of assumed that the maintenance on a system would be minimal once it's set up. Sure, maybe you have to add some panels and upgrade an inverter after a few years, or replace some batteries... is there something I'm missing?

 

[Kornbread]

Thinking out loud, their seems to be some good bargains in the ~400watt solar ($.25/watt) panel crowd.

Personally, my maintenance hasn't been as much the maintenance part, as it is the upgrade and make it bigger bug.

How far away will the panels be from the rest of the system? Have you calculated your power needs?

 

[HighTechLab]

Actually this was rattling around in my head all evening and you make an interesting point... I had sort of assumed that the maintenance on a system would be minimal once it's set up. Sure, maybe you have to add some panels and upgrade an inverter after a few years, or replace some batteries... is there something I'm missing?

With lithium, not much maintenance. They started with flooded lead-acid however. But there is still maintenance like oil changes on the generator, refueling, cleaning panels, etc.

 

[Hedges]

This one has 3x 600V (max) inputs rated 15A Imp per input, and you can parallel A and B inputs for 30A
Largest model (supposedly due this quarter) has 4 input so C and D could also be paralleled.

If you made an SE facing array of your 18A panels, and an SW facing array, those two in parallel would not exceed 30A so no clipping.

https://files.sma.de/downloads/SBSE-US-DS-en-25.pdf

That one won't work off-grid without an another box, not yet offered.

Here's one that might be a better choice, 3x 600V inputs rated 30A, 22A, 22A.
This is an AIO so all you need.

https://www.midnitesolar.com/pdfs/MN15-12KW-AIO_frontBack.pdf

Available from our esteemed member who just posted above me, "HighTechLab"

MidNite TheOne - 11.4kW Hybrid All-In-One Inverter

The New MidNite Solar All-In-One Inverter is perfect for larger systems. Coming with 3 separate MPPTs and 11.4 kW of nominal power, this inverter can ensure that important loads are always powered. With the MidNite name, this inverter is reliable and well-tested, resulting in an amazing unit...

www.currentconnected.com

 

[JaimeZX]

Thinking out loud, their seems to be some good bargains in the ~400watt solar ($.25/watt) panel crowd.

Personally, my maintenance hasn't been as much the maintenance part, as it is the upgrade and make it bigger bug.

How far away will the panels be from the rest of the system? Have you calculated your power needs?

Yeah, I'm SO TORN on this right now. On one hand I can get a pallet (36) of the Trina 620W panels delivered to my front door for $4700. On the other hand... most of them will probably go in the shed for a couple of years because my *immediate* requirements are not the *full array*. On the OTHER hand, with pending tariffs... who knows when I can get 21kw of panels for under $5k again?

Calculating power needs of a house not yet built has been an exercise in frustration, so I estimated that 21kw of panels should give me ~70kwh of juice most nice days, which is a bit more than I'm using in my current house... which is smaller than the planned retirement house but I'm also on-grid so not trying as hard to conserve... Based on the online solar calculators, in central VA it comes out to ~71-96kwh/day (before clouds).

This one has 3x 600V (max) inputs rated 15A Imp per input, and you can parallel A and B inputs for 30A
Largest model (supposedly due this quarter) has 4 input so C and D could also be paralleled.

If you made an SE facing array of your 18A panels, and an SW facing array, those two in parallel would not exceed 30A so no clipping.

https://files.sma.de/downloads/SBSE-US-DS-en-25.pdf

That one won't work off-grid without an another box, not yet offered.

Here's one that might be a better choice, 3x 600V inputs rated 30A, 22A, 22A.
This is an AIO so all you need.

https://www.midnitesolar.com/pdfs/MN15-12KW-AIO_frontBack.pdf

Available from our esteemed member who just posted above me, "HighTechLab"

MidNite TheOne - 11.4kW Hybrid All-In-One Inverter

The New MidNite Solar All-In-One Inverter is perfect for larger systems. Coming with 3 separate MPPTs and 11.4 kW of nominal power, this inverter can ensure that important loads are always powered. With the MidNite name, this inverter is reliable and well-tested, resulting in an amazing unit...

www.currentconnected.com

Nice, those look promising. In the meantime... for the near-term project of a small setup for our little cottage, I figure I'd use a few of the panels and a smaller off-grid inverter-MPPT to cover things there. This has thrown me another challenge, insofar as my County requires UL1741 on inverters. Originally I was looking at the EG4 3000 EHV 48v Inverter-Charger as most-likely sufficient for the small project, but... no UL1741 as far as I can tell. So now I am pushed towards the EG4 6000XP at double the price. Which isn't really the end of the world, just a bit of overkill I suppose.

 

[Koyaanisqatsi]

If you made an SE facing array of your 18A panels, and an SW facing array, those two in parallel would not exceed 30A so no clipping.

 

[Kornbread]

4mppts, 500v pv max, 14amp mppt max, $1.8 - $3k. UL certs but not sure if it meets your specific ul needs. Listed on the California Energy Commission Solar Equipment List.

NHX Series – Watts247 Wholesale

watts247.com

 

[DIYrich]

Separate charge controller

EG4 Solar Charge Controller MPPT | 500VDC 100A | MPPT100-48HV

EG4 MPPT100-48HV Solar Charge Controller: Efficiently manages up to 500VDC, 100A for optimal solar energy conversion and battery charging.

signaturesolar.com

If you want to stay Victron, this is 450v, 16-18a

SmartSolar MPPT RS - Victron Energy

The SmartSolar MPPT RS solar charge controllers are Victron's solution for systems with large series connected PV arrays charging 48 V DC battery banks.

www.victronenergy.com

 

[wpns]

Hi all! So I'm planning a ~21kw ground array and looking at some of the new Trina 650-700W panels, (Imp ~18.5A) and I have a question... (Availability & delivery issues aside!)

Where do you get suitable MPPT/inverters for these things?

Originally I was looking at Victron but they all seem to have max solar input currents of around 13A. I see some EG4s with 18V input currents (Ex: EG4 6000XP), which I guess should be okay... the 620W Trinas put out 15A so the EG4s should be good enough there...

But even then, if I use the Victron "what do I need?" website and pick more "normal" 420W panels, I can only put 3-5 in a string before they don't have any recommended products.

So...
Q1: Am I missing something? I know at least some of y'all have 20kw+ arrays, is there a reason why I can't find an MPPT with that kind of input current?

RELATED: So if I look at the EG4 6000XP as the "biggest" MPPT I can find, the relevant info seems to be
Max usable input current - 17A... MPPT Operating range 120-385VDC ... Nominal MPPT Voltage 320VDC ... Maximum utilized solar power 8000W. (4000W per MPPT).
So (with the 620W panels @ 15A x 41.4V ) that would be two strings of 6 (3726W x2 = 7452W). Or with 445W panels (15.1A x 29.5V), two strings of 9 for 8010W total.

Q2: Both of the above examples math out to well under 320VDC (6 x 41.4 = 248.4V) & (9 x 29.5 = 265.5V). Am I better served by finding panels that will string out to get me as close to 320V as possible? (Or, finding an inverter with nominal ~250VDC operating?) Or is that not a big deal?

Q3: The next question becomes "huge buck converter time." Because if the ground array is going to be some distance from the house then I'll want to push the voltage as high as possible to minimize line losses... Both of the Trina panels have max voltages of 1500, so in theory I could put all 33 of the 620W panels in series for 1242VDC before the underground run to the house... but then I need to drop it to ~450VDC safely somehow. Guess I could put three inverters in parallel but if one shuts down for some reason the other two would spike to over 600V, pesumably not good.

Thoughts on this, anyone? I'd be most grateful.

EG4 FlexBoss21 will take 21KW of PV, but also GridBoss plus some number of EG4 inverters will give you more MPPTs and more power and some redundancy.

Can you get the grid install for less money if you want less power? If you have inverters and can do grid shaving, then maybe a 60A feed would suffice, if your average load is less than 14KW.

While maintenance is low initially, you'll want to have a plan for the future when you can no longer DIY. That plan might be "The solar industry is just taking off, and in 10-20 years there are going to be mature, reliable players who can fix or replace my system when I can no longer do so (and my heirs can't/don't-want-to)".

 

[DIYrich]

Q3: The next question becomes "huge buck converter time." Because if the ground array is going to be some distance from the house then I'll want to push the voltage as high as possible to minimize line losses... Both of the Trina panels have max voltages of 1500, so in theory I could put all 33 of the 620W panels in series for 1242VDC before the underground run to the house... but then I need to drop it to ~450VDC safely somehow. Guess I could put three inverters in parallel but if one shuts down for some reason the other two would spike to over 600V, pesumably not good.

No. You can't put 3 charge controllers in series to spread the voltage, or parallel to share the current.

Also wire is typically rated for 600v, maybe 1000v.