Any suggestions for adding capacity and backup power to my current SMA Sunny boy system

drewjet

New Member
Joined
Aug 13, 2021
Messages
10
I am currently in the process of installing an SMA SunnyBoy 7.6 KW (Grid-Tie split phase 120/240v) system, with 30 Qcell 320 watt panels. I am awaiting my permit to finish install and to get the power company to reprogram my meter to read backwards. Right now I have 15 panels on my roof "testing the system", and can see that I am not getting enough power to cover all my current needs, plus future needs. When I bought the panels I originally bought used Canadian Solar panels, however they kept tripping the Ground fault Isolation on the Sunny Boy. The seller took them back and made me a good deal on the New Qcells that I now have. He had 43 of them and so I took them all. 30 panels will put me at max with the Sunny Boy (slightly over-paneled) so I intend to add a second inverter.

So this is my question and what I want to do. I want the second inverter to be a Hybrid. Under normal conditions it will be A/C coupled/grid-tied and create enough electricity that I can cover all my electric needs including being able to run the A/C in my shop 24/7 to keep the humidity here in Central Florida under control. Then when the grid goes down, I can Isolate from the grid run the Hybrid Inverter in Off-grid mode, and it should trick my SunnyBoy into turning on and connecting. Later I can add batteries/generator into the system for night time off-grid coverage.

It looks like the Grid-Tied Inverter Delta H6 6000W can do everything I need. I called the Ebay seller of them and they thought it could, but didn't want to commit to it. What do you guys think?
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,434
Isn't the Delta an orphan product which only works with the Tesla (DC port) battery that never made it to market?
If so, I understand it only works as a batteryless inverter, probably grid-tie.

30 panels is max for your Sunny Boy, and you have 43? If so, I think that could be the perfect amount of over-paneling to not be over-paneled at all.
With all panels oriented in one direction, power output makes a curve during hours of the day.
If you split your panels into two sub-arrays and orient them 90 degrees apart (e.g. 10:00 AM and 4:00 PM sun), peak wattage should be about 0.7x has high as if all were oriented the same. That would remain within Sunny Boy's wattage limit but extend hours, increasing Wh/day to about 1.4x as much.

You need to consider min/max voltage of the MPPT inputs, max current, and max short-circuit current.
While separate MPPT for different orientations is optimum, having two orientations paralleled into a single MPPT is only about a 2% decrease in power captured (so long as one doesn't get significant partial shadowing.) Given the current limits of your MPPT inputs, you may have to parallel all of them to get away with the parallel strings. Or, have two strings of different orientations on each input.

Consider PV panels 7s2p connected to each of three MPPT inputs. See how the voltage and current figures work out.

This one? If so, probably back to the idea of connecting the three MPPT together and a different series/parallel combination.



Hybrid? What you may want is Sunny Island (or Sunny Boy Storage), which will have a battery and work with Sunny Boy to provide backup during grid failures.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,434
... By the way, have you determined how much PV breaker you're allowed to install?
NEC allows main breaker + PV breaker to total 120% of busbar rating.
For a typical panel with 200A busbar and 200A main breaker, that means 40A breaker for PV can be installed (at far end of panel)
Maximum continuous draw 80% of breaker rating, so 32A x 240V = 7680W.
Therefore, everybody and his brother offers a 7.7kW GT PV inverter.

If you happen to have a panel with 225A busbar like Square-D QO, then 70A PV breaker is allowed.

The rules of physics and practice of electrical engineering don't actually have such a limit. I don't believe there is a technical problem up to same rating as the main breaker (e.g. 200A, two 100A PV breakers at the end of busbar), so long as they never get relocated. (Feeding both ends of the busbar, no point carries more than 200A. But if relocated adjacent to main breaker, busbar would carry 400A. NEC considered all this and threw us a bone with the 120% rule.)
 

mrzed001

Voice of reason
Joined
Apr 10, 2020
Messages
721
Location
Hungary - EU
Hybrid? What you may want is Sunny Island (or Sunny Boy Storage), which will have a battery and work with Sunny Boy to provide backup during grid failures.

Sunny Island is a bit expensive.
I would go with a Victron Multiplus II or Quattro ... and with a 48V battery pack
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,434
Yes, expensive MSRP but very capable.
They can be had for about $2000 to $3000, thanks to DC Solar's shenanigans.
One Sunny Island plus 120/240V transformer would work with your Sunny Boy (but probably only off-grid)
On-grid you'd have to program for 6.7kW limit due to pass-through relay. And then you'd have more current than what NEC allows for PV backfeed (depending on busbar rating.)
So you'd really need two Sunny Island. You need 120/240V pass-through to grid. With two, good for more PV up to 13 kW.

Sunny Boy Storage is their newer offering, and offers features of load shaving and shifting. But by the time you add ABU for transformer and transfer switch it comes to $5k or $6k. It's surge current is limited. Biggest downside is the expensive 400V lithium battery.

Does the Multiplus manage AC coupled GT PV inverters? How much pass-through to grid?



What do you plan to spend on battery? That can be more than an inverter, depending on capacity and type. Looks to me like DIY LiFePO4 (or used EV packs) can be economical. They're a complete project by themselves. I have an undersize AGM bank, since just for occasional grid failures.
 

drewjet

New Member
Joined
Aug 13, 2021
Messages
10
Isn't the Delta an orphan product which only works with the Tesla (DC port) battery that never made it to market?
If so, I understand it only works as a batteryless inverter, probably grid-tie.

30 panels is max for your Sunny Boy, and you have 43? If so, I think that could be the perfect amount of over-paneling to not be over-paneled at all.
With all panels oriented in one direction, power output makes a curve during hours of the day.
If you split your panels into two sub-arrays and orient them 90 degrees apart (e.g. 10:00 AM and 4:00 PM sun), peak wattage should be about 0.7x has high as if all were oriented the same. That would remain within Sunny Boy's wattage limit but extend hours, increasing Wh/day to about 1.4x as much.

You need to consider min/max voltage of the MPPT inputs, max current, and max short-circuit current.
While separate MPPT for different orientations is optimum, having two orientations paralleled into a single MPPT is only about a 2% decrease in power captured (so long as one doesn't get significant partial shadowing.) Given the current limits of your MPPT inputs, you may have to parallel all of them to get away with the parallel strings. Or, have two strings of different orientations on each input.

Consider PV panels 7s2p connected to each of three MPPT inputs. See how the voltage and current figures work out.

This one? If so, probably back to the idea of connecting the three MPPT together and a different series/parallel combination.



Hybrid? What you may want is Sunny Island (or Sunny Boy Storage), which will have a battery and work with Sunny Boy to provide backup during grid failures.
Thank you for taking the time to help, I appreciate it.

The Delta is Orphaned, which is why it is priced so low, for what I believe to be a quality inverter about 1/3 the price of my Sunny Boy, and it is capable of Off-Grid.

At 30 panels I am already over-paneled, with only 15 panels currently connected, I am seeing peaks of 4300 watts.

My building that has the panels on it, is a due South facing roof, so orienting panels with an East or West Orientation would require mounting systems that I don't want to deal with.

Yes those are the panels I have.
 

drewjet

New Member
Joined
Aug 13, 2021
Messages
10
Yes, expensive MSRP but very capable.
They can be had for about $2000 to $3000, thanks to DC Solar's shenanigans.
One Sunny Island plus 120/240V transformer would work with your Sunny Boy (but probably only off-grid)
On-grid you'd have to program for 6.7kW limit due to pass-through relay. And then you'd have more current than what NEC allows for PV backfeed (depending on busbar rating.)
So you'd really need two Sunny Island. You need 120/240V pass-through to grid. With two, good for more PV up to 13 kW.

Sunny Boy Storage is their newer offering, and offers features of load shaving and shifting. But by the time you add ABU for transformer and transfer switch it comes to $5k or $6k. It's surge current is limited. Biggest downside is the expensive 400V lithium battery.

Does the Multiplus manage AC coupled GT PV inverters? How much pass-through to grid?



What do you plan to spend on battery? That can be more than an inverter, depending on capacity and type. Looks to me like DIY LiFePO4 (or used EV packs) can be economical. They're a complete project by themselves. I have an undersize AGM bank, since just for occasional grid failures.
Cheapest Sunny Island on Ebay is $2250, so 2 of them to do the job of the Delta H6 seems a waste to me, other than not getting Battery Backup with the H6. (which may be possible, there looks to be a few guys working on it.)

Battery backup is a low priority for me right now. 97% of what I am after right now is grid-Tied. I can get by with a generator when rarely needed in the night.

My biggest concern right now is what happens when the grid is down during daytime. The way I see it is, I disconnect from the mains, put the Delta H6 into off-grid mode, with its output connected to the same breaker panel as the Sunny Boy. This effectively creates my own grid. The Sunny Boy should see this grid and add in its 7600 watts. The question is will this hurt the Sunny Boy? If I am not consuming all the power the Sunny Boy wants to put out, will it just produce less power?
 

mrzed001

Voice of reason
Joined
Apr 10, 2020
Messages
721
Location
Hungary - EU
Yes, expensive MSRP but very capable.
They can be had for about $2000 to $3000, thanks to DC Solar's shenanigans.
One Sunny Island plus 120/240V transformer would work with your Sunny Boy (but probably only off-grid)
On-grid you'd have to program for 6.7kW limit due to pass-through relay. And then you'd have more current than what NEC allows for PV backfeed (depending on busbar rating.)
So you'd really need two Sunny Island. You need 120/240V pass-through to grid. With two, good for more PV up to 13 kW.

Sunny Boy Storage is their newer offering, and offers features of load shaving and shifting. But by the time you add ABU for transformer and transfer switch it comes to $5k or $6k. It's surge current is limited. Biggest downside is the expensive 400V lithium battery.
Yes, that 2-400Vdc battery banks this type of systems need ... they are extremely expensive

Does the Multiplus manage AC coupled GT PV inverters? How much pass-through to grid?

If I remember correctly them Multiplus II and Quattro both manage AC coupling.
Remember that big shipping container system?
Fronious AC coupled with Victron.

What do you plan to spend on battery? That can be more than an inverter, depending on capacity and type. Looks to me like DIY LiFePO4 (or used EV packs) can be economical. They're a complete project by themselves. I have an undersize AGM bank, since just for occasional grid failures.
DIY pack is the cheapest and biggest.
Some are afraid from it ... the middle road is 12V batteries like BattleBorn
But for really not handy people ... there are the full pre-built battery packs like Pylontech. Full BMS support with Victron.
 

mrzed001

Voice of reason
Joined
Apr 10, 2020
Messages
721
Location
Hungary - EU
Cheapest Sunny Island on Ebay is $2250, so 2 of them to do the job of the Delta H6 seems a waste to me, other than not getting Battery Backup with the H6. (which may be possible, there looks to be a few guys working on it.)

Battery backup is a low priority for me right now. 97% of what I am after right now is grid-Tied. I can get by with a generator when rarely needed in the night.

My biggest concern right now is what happens when the grid is down during daytime. The way I see it is, I disconnect from the mains, put the Delta H6 into off-grid mode, with its output connected to the same breaker panel as the Sunny Boy. This effectively creates my own grid. The Sunny Boy should see this grid and add in its 7600 watts. The question is will this hurt the Sunny Boy? If I am not consuming all the power the Sunny Boy wants to put out, will it just produce less power?
You do not need to put anything to off-grid mode :) It happen automatically.
A relay/PLC senses the blackout and disconnects your main from grid. That needs 5-60 seconds and in this time you do not have power.

The Victron or Sunny Island starts to produce power. The Grid-tie Sunny Boy inverter senses it and starts to produce power.
If it makes too much Victron rises the frequency a little bit. The grid-tie senses it and lower the power creation or even shuts down ... so it controls the Sunny Boy.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,434
Cheapest Sunny Island on Ebay is $2250, so 2 of them to do the job of the Delta H6 seems a waste to me, other than not getting Battery Backup with the H6. (which may be possible, there looks to be a few guys working on it.)

Battery backup is a low priority for me right now. 97% of what I am after right now is grid-Tied. I can get by with a generator when rarely needed in the night.

My biggest concern right now is what happens when the grid is down during daytime. The way I see it is, I disconnect from the mains, put the Delta H6 into off-grid mode, with its output connected to the same breaker panel as the Sunny Boy. This effectively creates my own grid. The Sunny Boy should see this grid and add in its 7600 watts. The question is will this hurt the Sunny Boy? If I am not consuming all the power the Sunny Boy wants to put out, will it just produce less power?

Sunny Island is primarily a battery UPS, which does frequency shift to manage Sunny Boy (or others). It is possible to use it for grid feeding if you have DC charge controllers, probably not an optimal system.

If Delta will work off-grid without batteries, that can be a useful feature. PV needs to be sufficient for motor starting, but for a refrigerator it could be. If the price is right, worth considering. Does it produce 120/240V split phase without grid?

Maybe the battery interface will get reverse engineered and be practical. A 400V battery is 100 or so cells, so a lot of BMS. Many UPS have used high voltage lead-acid banks, could be an economical alternative. But communication probably required to get Delta working.

If you connect Sunny Boy downstream from Delta, I don't think Delta does frequency-watts to manage it. This configuration probably doesn't work.

Newer Sunny Boy also provide batteryless backup, which they call "Secure Power". It has to be enabled manually, and puts out up to 2000W at 120V.

You do not need to put anything to off-grid mode :) It happen automatically.
A relay/PLC senses the blackout and disconnects your main from grid. That needs 5-60 seconds and in this time you do not have power.

The Victron or Sunny Island starts to produce power. The Grid-tie Sunny Boy inverter senses it and starts to produce power.
If it makes too much Victron rises the frequency a little bit. The grid-tie senses it and lower the power creation or even shuts down ... so it controls the Sunny Boy.

How much power can Victron pass through from Sunny Boy to grid? Does it produce split-phase 120/240V off grid?

Sunny Island is 120V and passes through 56A. Two of them make 120/240V split phase. Three make 120/208Y. Four make 120/240V with 112A pass through.

Sunny Boy (new models) needs to be configured for frequency-watts, then it is automatic.
Older models have other settings, most work with Sunny Island but some do not.

Probably Delta doesn't implement UL-1741SA required for permitted installations, but should be UL-1741 so safe for grid tie.


Unless you find an economical battery inverter that does frequency shift, a low cost grid tie hybrid with battery and some of the panels would be a way to go. Does something from GroWatt fit the bill?
 

mrzed001

Voice of reason
Joined
Apr 10, 2020
Messages
721
Location
Hungary - EU
Sunny Island is primarily a battery UPS, which does frequency shift to manage Sunny Boy (or others). It is possible to use it for grid feeding if you have DC charge controllers, probably not an optimal system.
As I see it has 2 AC ports. One for the grid and one for the protected load side.
Victron inverters have it too. This is the UPS function with the inner transfer switch. I am not sure is Sunny Island has real 0 sec transfer (Like MPP Solar MK and LV-MK) ... Victron does not have it.
Both can with outer transfer switch disconnect house from main.
Both can create a microgrid and with frequency shifting control grid-tie inverters power generation



If Delta will work off-grid without batteries, that can be a useful feature. PV needs to be sufficient for motor starting, but for a refrigerator it could be. If the price is right, worth considering. Does it produce 120/240V split phase without grid?

Maybe the battery interface will get reverse engineered and be practical. A 400V battery is 100 or so cells, so a lot of BMS. Many UPS have used high voltage lead-acid banks, could be an economical alternative. But communication probably required to get Delta working.
In many of this 400Vdc batteries is really a 48Vdc battery, and a very expensive boost converter makes the 400V from it.

If you connect Sunny Boy downstream from Delta, I don't think Delta does frequency-watts to manage it. This configuration probably doesn't work.

Newer Sunny Boy also provide batteryless backup, which they call "Secure Power". It has to be enabled manually, and puts out up to 2000W at 120V.



How much power can Victron pass through from Sunny Boy to grid? Does it produce split-phase 120/240V off grid?
Sunny Island is 120V and passes through 56A. Two of them make 120/240V split phase. Three make 120/208Y. Four make 120/240V with 112A pass through.
Victron can do 120/240 split phase.
Also it can produce the phase to its AC in port too. So it is like:
grid -> relay disconnector + meter -> grid-tie and/or load 1 -> Victron -> protected load
So with Victron it is possible to use equipments that need even more than the grid can provide (no grid-tie and load1 can be grid + Victron generated W together)
Bypass is made by relay in Victron (from grid to protected load), so it can pass through a lot (must check manual for exact number).
Also has an AC out 2 for expandable loads (if going low it can shut it down while AC out1 the protected load still gets power)
Victron2.png
ps: Sunny Island's diagrams a bit stupid. This I call a system diagram.

Unless you find an economical battery inverter that does frequency shift, a low cost grid tie hybrid with battery and some of the panels would be a way to go. Does something from GroWatt fit the bill?

You mean Off-grid with grid support inverter ? There is a lot : Growatt, MPP Solar, EASun ...
Hybrids are expensive.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,434
That Victron diagram shows a single phase and neutral connected to utility panel. Victron does offer an auto-transformer for connection to loads side.
With OP's 7.7kW Sunny Boy, if converted to 120V by transformer and connected to a single phase of utility, would deliver 64A and should have 80A breaker, exceeding NEC for most breaker panel configurations.
He wants to add more PV connected to the hybrid, for about 11 kW total. Depending on current limit, he may have to keep some PV direct to grid, not available during backup operation, only using PV connected to the hybrid.

Is there a Victron model and diagram showing two lines (possibly plus neutral) connected to grid?
It is possible to make that work without neutral, if inverter produces isolated 240V and autotransformer establishes neutral.

SMA used to provide better documentation including theory of operation for past products. I need to understand how it works to know if it works.
I had thought their auto-transformer and relay box for use with a single Sunny Island would allow high current bypass to loads and Sunny Boy, but studying the schematics I decided it didn't. I wanted 200A 120/240V bypass, and connecting 12kW PV without it going through the 6.7kW pass-through limit of one Sunny Island.



I had grid-tie Sunny Boy for 15 years before installing Sunny Island. Couldn't justify the price. Once I did, discovered my old US market Sunny Boys didn't have firmware for frequency shift power control, so replaced with new old stock models that do.
It was only liquidation prices on Sunny Island which made this half way economical. It was still an over-priced luxury.
 

mrzed001

Voice of reason
Joined
Apr 10, 2020
Messages
721
Location
Hungary - EU
That Victron diagram shows a single phase and neutral connected to utility panel. Victron does offer an auto-transformer for connection to loads side.
I think Victron inverters can be paralleled like some MPP Solar like for single phase, split phase, 3 phase.

With OP's 7.7kW Sunny Boy, if converted to 120V by transformer and connected to a single phase of utility, would deliver 64A and should have 80A breaker, exceeding NEC for most breaker panel configurations.
He wants to add more PV connected to the hybrid, for about 11 kW total. Depending on current limit, he may have to keep some PV direct to grid, not available during backup operation, only using PV connected to the hybrid.

Is there a Victron model and diagram showing two lines (possibly plus neutral) connected to grid?
It is possible to make that work without neutral, if inverter produces isolated 240V and autotransformer establishes neutral.

SMA used to provide better documentation including theory of operation for past products. I need to understand how it works to know if it works.
I had thought their auto-transformer and relay box for use with a single Sunny Island would allow high current bypass to loads and Sunny Boy, but studying the schematics I decided it didn't. I wanted 200A 120/240V bypass, and connecting 12kW PV without it going through the 6.7kW pass-through limit of one Sunny Island.



Thats what I talking about. Finally a system diagram :)
Here in the pdf last page you can see that it has AC in from grid, and AC out for protected load.
This is a one unit hybrid system (grid-tie back to grid through it, off-grid with inner separator, also extra AC coupled in protected load side with grid-tie inverters).

The grid-tie inverters are in the AC Out (protected load) side.
Victron can do it so that the grid-tie inverters are in the AC in side.
So for selling to grid does not need the generated PV power to flow through the inverter.

Check this pdf, page 2: https://files.sma.de/downloads/SI44M-80H-13-DS-en-21.pdf
Here it seems that PV generated power does not flow through the Sunny Island. It is an AC coupled hybrid system (grid-tie direct to grid, off-grid with outer separator and then AC coupled with grid-tie inverters ... no protected load side, not a one unit hybrid ) .
 

drewjet

New Member
Joined
Aug 13, 2021
Messages
10
Thanks guys, I appreciate the input.

The Delta H6 does has 2 separate ports for A/C, both are split phase 120/240. I believe that one goes to grid, the other to protected loads, not sure if it is Instantaneous or not, but that doesn't bother me. I believe I would need to use a switching unit to allow one or the other to power my grid, but never both at the same time.

My Sunny boy is a newer model, so I assume it does frequency shift power control, I will just have to program it. Not sure if the Delta will use frequency shift power control on its off grid mode. But again it is low on my list of priorities.

I do have access to a 400 volt battery. I have a Chevy volt, and I don't think it would be too difficult to tap into it, but I think without communication from the battery in a protocol only the Delta talks would I be able to use it.

At this point for the $550 the Delta costs, I think I will roll the dice on it.

My Sunny Boy does have the 2000 watt secure power option, so I will definitely get that going, plus I would be able to manually switch from grid tie to off grid with the Delta H6 would give me all the power I need during daylight grid outages, and just use my generator for night time power needs.

Once I get it, I will report back here with some findings.

This video
does a nice job showing how to add off-grid with battery backup to a grit tied system.
 

MurphyGuy

Solar Addict
Joined
May 20, 2020
Messages
681
My Sunny Boy does have the 2000 watt secure power option, so I will definitely get that going, plus I would be able to manually switch from grid tie to off grid with the Delta H6 would give me all the power I need during daylight grid outages, and just use my generator for night time power needs.
The SPS on the Sunny Boy isn't all that great.. it has zero over-load capacity so it will only start small motors.. it also only works when the sun is shining.

I have two Sunny Boy's on my array. After messing with the secure power supply (SPS) for a while, I quickly discovered its best use was to hook up a common automotive battery charger to charge 12 volt deep cycle batteries and then run a 12 volt inverter off those bats. The inverter can be sized for whatever you want and the batteries extend the power produced during the day into the evening.

If you monitor and calculate correctly, you can tap almost the entire 2000 watts and pump it into the batteries.. I actually had 4 battery chargers going one time.
 

mrzed001

Voice of reason
Joined
Apr 10, 2020
Messages
721
Location
Hungary - EU

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,434
There are LG RESU 48V battery and LG RESU-H 400V battery. I had assumed more small cells in series for the 400V, which would require more channels of BMS. Do you think that was done with boost converter? Only the RESU-H (and only some of the units) were recalled due to fires.

I would consider 10, 12V car batteries in series for input to a Sunny Boy. Maybe a bunch of surplus sealed UPS batteries. There should be a precharge circuit used when connecting. Ideally would charge while PV is producing, but some effort to avoid recharging battery from inverter powered off same battery.
 

mrzed001

Voice of reason
Joined
Apr 10, 2020
Messages
721
Location
Hungary - EU
There are LG RESU 48V battery and LG RESU-H 400V battery. I had assumed more small cells in series for the 400V, which would require more channels of BMS. Do you think that was done with boost converter? Only the RESU-H (and only some of the units) were recalled due to fires.

I would consider 10, 12V car batteries in series for input to a Sunny Boy. Maybe a bunch of surplus sealed UPS batteries. There should be a precharge circuit used when connecting. Ideally would charge while PV is producing, but some effort to avoid recharging battery from inverter powered off same battery.
Here are some techs who repair GT, OG inverters, and anything EV related (charger, inverter, battery, ...) in Toyota/Lexus, Nissan, Tesla ... everything.
And also write articles about them with pics, sometimes reverse engineered circuit diagrams (in hungarian language so max google translate can make it english ... but even for that was it too big, so I translate some parts).

One of them dissected a RESU 10kWh 400V for Sunny Boy Storage (CAN bus version).
LG_Resu_2.png

Technically he wrote a love letter about this unit :)
LGX JH3 63Ah battery cells, 42 pcs. 6 module 7-7 cells.
3 BMS ... 3x48V battery in serial.
Double way DC/DC converter. It converts battery 144V to 400V for discharge and converts the 400V from solar inverter to 144V for charge.
LG_Resu_1.png
LG_Resu_3.png
Galvanic separation with around 2.500V insulation potential between the inverter and the battery.
Speculates the 48V version has the same design because like here the engineers would not allow direct charge to the batteries.
The double way DC/DC converter is in reality 3 resonant converter. Depending on load can 1, 2 or all 3 work at the same time.
Also can cycle them so if one worked/hot then set to rest/cool while other works.
 

drewjet

New Member
Joined
Aug 13, 2021
Messages
10
My Delta H6 came in. Then I had to go out of town for work. So when I got back, I set up a quick and dirty test with 6 panels laying flat on a trailer. Grid-tie works great, seems to put out just slightly more watts than 6 panels on my roof with a 13 degree angle facing due South connected to the SunnyBoy.

Power is always available to the protected loads panel output, until I open the breakers on the grid-tie connection. The power goes off from the protected loads panel for about 2 seconds then automatically goes into off-grid mode. I only hooked a strip LED to the output, but it did just fine. 240 volt split-phase with the frequency at 59.7 hz. The battery output was around 515 volts. My assumption is that since it is not seeing a battery it is not raising the frequency to signal other grid tie inverters to back off.

I haven't had the time yet to try and create my own mini grid isolated from the grid to see if the SunnyBoy will come online, and to see what it does for power output.

I am not sure if I can come up with over 500 volts worth of battery to try and trick the Delta H6 to think it has a full battery. So still working on how best to implement the 2 inverters.

On the plus side, my permit finally came through for my Sunny Boy installation, so I can work on getting that done. I hope getting the power company to reprogram my smart meter is easier than getting the permit from the county. Once all that is done then I can move onto adding the 13 extra panels.

I have been looking at some DIY solar trackers, and may play with that at some point as well.
 
Top