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Sunny Boy frequency-shift regulation of power output - which models work per spec?

Hedges

Hedges

I See Electromagnetic Fields!
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Mar 28, 2020
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I'd like to hear from you guys as to your experience with various model SMA Sunny Boy on Sunny Island systems.
I'm not seeing them respond properly to frequency shift in "Backup" (default = UL1741 & backup = On All Phases or On, depending on model and interface.) I'm only getting it to work in "Off-Grid" (default = island or off-grid)

Here's one of SMA's documents on the topic:

https://files.sma.de/dl/7910/SB-OffGrid-TI-US-en-21.pdf

I have SWR 2500U, with a few versions of ROM. One was supposed to respond to RS-485 telling to switch from on-grid to backup, but it always drops off at 60.5 Hz. none of the ROMS have an off-grid option.

I have SB 10000TLUS-12. I can't see it with Sunny Boy Control & RS-485, but I'm able to configure it with Sunny Explorer and Speedwire. I then reinstall RS-485. When set to on-grid (default = UL1741, backup = off) it delivers full power until frequency hits limits (something like +0.5/-0.7 Hz from 60 Hz nominal) then drops off. Set for backup (default = UL1741, backup = on all phases) it stays on line producing full power all the way up to 64.8 Hz, then drops off. When frequency has decreased back to 63 Hz it comes back online, and the cycle repeats. Relays bang on and off loudly about every minute. When set offgrid (default = island), then everything works great. It'll hover just below 62 Hz with power output reduced to match load. With larger loads applied, frequency is reduced by Sunny Island and Sunny Boy delivers more power.

What is your experience? Which models if any perform power reduction in response to frequency when set to "backup"?
 
With sma stuff, its usually missing hardware, software or conflocting settings. Tell Tim i said hi!
 
kernel said:
With sma stuff, its usually missing hardware, software or conflocting settings. Tell Tim i said hi!
Click to expand...

I did read all the manuals, also app notes, cover to cover. That's not my usual style, but considering how long I've been planning to do this and how much Sunny Islands used to cost, I made an exception.

So I'm hoping to hear whether other people had the same experience with SB 10000TLUS-12, or if anyone got it to work.

I do seem to have the hardware talking, because SB changes frequency limits when connected by RS-485 to SI.
For a time I thought SI wasn't talking because I couldn't capture it with a scope. Sunny Boy Control talked every couple seconds, and I was able to trigger on that. Maybe SI only speaks once.
I noticed that pullup/down was only addressed in one document as coming from an interface like Sunny Boy Control. Sunny Boy also has jumpers for pullup/down, and I've set those so RS-485 works whether Sunny Boy Control is connected or not. I've now got an RJ45 feed-thru in one of the SI conduit openings so I can plug in either SBC or a terminator.
I watched operation with a frequency meter and ammeter on the AC line. On-grid works. Off-grid works. Backup doesn't reduce power output in response to frequency but does have wider frequency limits.

Since SWR 2500U wasn't responding at all to RS-485, I tried to manually set frequency and voltage parameters (for a unit I installed ROMS in that have fac-start and end parameters.) I set one voltage too low, 50% of nominal based on one document I saw, and it generated an error that voltage calculation by BFR and SRR disagreed. I used the command to reset error (which would only execute with older ROM reinstalled), and it didn't reset the error but did set ground fault. I reset ground fault by power cycling with fuse removed, but error remained. It is now unusable.

I'm curious which if any models actually do support grid-backup and not just offgrid. I suspect SMA used to have this working in some models but later the code got broken, and testing was insufficient to detect it. Probably some boolean logic that had both off-grid and backup mode enable wider frequency limits, but only off-grid enabled power reduction.

Software? Documents say I should be able to set SB 10000TLUS-12 parameters with Sunny Boy control, but it isn't recognized. Old firmware? Sunny Boy Control firmware update release notes don't mention supporting new inverter models so I haven't tried to update. With Sunny Explorer I was able to access it. I did have to get both PUK and GridGuard code to make the changes. I thought I had passwords (numeric) for the inverter, but newer software (don't see old revs posted) insisted on forcing me to change passwords, and still didn't let me set parameters. That seems to be a symptom of incorrect password; I encountered that again when I swapped Speedwire modules between two inverters. Used the original module and it was happy with the complex password I had set. If Sunny Island was sitting at 59 Hz, Sunny Boy was waiting for good grid frequency and ignored my commands to set island (off-grid) mode. I reconnected to the grid, frequency was 60 Hz, and once Sunny Boy was happy it would finally listen to my setting of default = island. The things you need to know, or figure out by trial and error ...

I expect bugs with software, that's why I'm trying to use these older models and not put it on the web. But I expected firmware to be relatively bug-free, with a simple protocol over RS-485.
 
I pulled my hair out for two seasons on these.... there is a similar system to yours i am going back to when the season opens.

No fun i know. Unfortunately connecting it to the web amd letting sma techs straighten out the firmware is likely the best thing to do. If the machines are incompatible its another story and sma would be non willing....

You got me on logic reset/ change and parameters outside intent of the manufacturer.

Of you blow the little fuse cartridge..... had an owner and electrician freaking out about the cartridge case!

Why did the ground fault protection actuate? Do you have a transformer?
 
kernel said:
I pulled my hair out for two seasons on these.... there is a similar system to yours i am going back to when the season opens.

No fun i know. Unfortunately connecting it to the web amd letting sma techs straighten out the firmware is likely the best thing to do. If the machines are incompatible its another story and sma would be non willing....

You got me on logic reset/ change and parameters outside intent of the manufacturer.

Of you blow the little fuse cartridge..... had an owner and electrician freaking out about the cartridge case!
.
Why did the ground fault protection actuate? Do you have a transformer?
Click to expand...

Fuse (for those not familiar with the SWR 2500U model) is a 1A fuse connecting negative side of PV string to earth. If any other part of the string shorts to ground, current flows, blowing the fuse. Sunny Boy detects voltage on its negative terminal is no longer zero, and stops drawing current. This is how ground-fault protection was implemented, interrupting current flow so it doesn't feed an arc and cause a fire.

The fuse didn't blow. SB simply set the ground-fault LED as if it had. I removed the fuse, cycled power, reinstalled the fuse and that fault went away. What set the fault was my issuing the SBC command "PV-Plant/Parameters/Memory Function = Reset Errors." Instead of that command resetting error "MSD-Vac" (which means BRF and SRR calculation of voltage disagree), it set the ground fault error.

They way I caused "MSD-Vac" was by setting VAC.min = 120 (half of 240V nominal.) I did that based on the stand-alone settings listed in SB-OffGrid-TI-US-en-19: "Vac.Min ‒50% VAC Nom, Vac.Max +20% VAC Nom". But the manual for this inverter lists 180V as the minimum range for this parameter. I was trying to manually set off-grid parameters, but now have an error "MSD-Vac" I can't reset. This is obviously just a bit set in non-volatile memory, but I only have SBC commands to access the inverter.

I always though the 2500 model was supported by Sunny Island, but turns out the SWR 2500 for European market may be but the SWR 2500U for US market may not. Also some model Sunny Boy may work with earlier Sunny Island models but not the SI-5048 or SI-6048. I was provided with BFR and SRR V8.97 ROMS which do have FAC-Start and FAC-Limit parameters, but I don't have the power reduction working.

According to SMA's off-grid parameters sheet, SB 10000TLUS-12 supports both backup and off-grid operation with Sunny Island, but no currently available inverters do; they only support on-grid or off-grid not backup (apparently because they don't have RS-485). That is why I bought this model second hand.

So you've had SMA remotely access your systems and set them up? Do you have any operating as grid backup with Sunny Island? If so, what model Sunny Boy? Did they set it to "default = Island" (which would be off-grid) or is it still "default = UL1741"?

I've had communication from SMA America support saying that SB7.7-1SP-US-41 can be used for backup by setting "Island". That is different from published documentation which says it must be set for the country standard. I can guess why the developers in Germany said to set country standard "UL1741" not "Island", but the reason isn't published.

"For PV inverters without backup operation, the country data set must be set to the locally typical value for grid-tie
PV systems as per UL1741. The PV inverter is then configured for operation on the utility grid. In the event of a utility
grid failure, the Sunny Island is unable to derate the PV inverters by means of Frequency-Shift Power Control (FSPC).
If there is an excessive supply of energy, the PV inverters will switch off."
 
Heard back from SMA:

"Our software specialist in Germany was able to review the code for the SB10000TLUS-12 and confirmed that in backup mode the FSPC function is not active. The SBXXTLUS-12 inverters all have the same code, and thus will be removed from the list of PV inverters that are backup mode compatible. There will be no further firmware releases for this family of inverters, as they have been discontinued.

The solution for this system will be to disable Backup Mode and program the inverters for Off-grid operation instead. This will allow them to respond appropriately to FSPC from the Sunny Island system, and it does not effect their operation when the system is still connected to the grid."

So it took a while, but they did investigate the issue and confirmed what I observed.

I replied, among other things:

"It is disappointing that SMA won't support its products within the "Warranty: 10 / 15 / 20 years" period they were offered with. So long as any customer's units are still under warranty, I think SMA should provide firmware updates especially when it turns out the product never met its original requirements."

Apparently it took me, one customer in perhaps a million, to point out what everyone else had missed. Of course, most of their customers are strictly grid-tie, not using Sunny Island. And some installers may have spotted the issue and set "off grid" instead of "backup". But I'm guessing many did use "backup" and it will perform poorly.
 
e97 said:
Thanks for sharing. I was planning to get the Sunny Island 6048 but will no longer do so - leaning even more towards the Sol-Ark!
Click to expand...

SI6048 is quite good. The issue I ran into was a functionality of SB 10000TLUS-12, which didn't respond properly to RS-485 signalling. It does work properly with off-grid a.k.a. island mode.

SMA's latest Sunny Boy, the series that includes. the 7.7 kW -40 and -41 models, doesn't have an RS-485 adapter available. It does have the off-grid mode.

SMA is now telling me the thing to do is use off-grid setting with Sunny Island, even if for grid-backup and not strictly off-grid. It does work; I just challenged them on that because SMA Germany previously published documents saying to use UL1741 settings (not off-grid) for inverters without backup option.

With Si6048 you'll either need a 120V/240V transformer or else two (or four) Si6048 to produce split phase. You also want a load-shed relay to disconnect the house in case of low battery while keeping Sunny Boy on line.

That's all assuming a grid-backup setup. For off-grid, you can use a different brand charge controller and a shunt.

It may be that The Sunny Island 8.0 currently being sold in Europe will come here. It uses a different bus (speedwire maybe?) that the new Sunny Boys do support.

There is also Sunny Boy Storage which works only with high voltage lithium batteries, and does talk to the new Sunny Boys. As a backup system, it requires a separate box providing transfer switch and 120V/240V transformer. Only a single 6 kW Sunny Boy Storage can be used (but you could have multiple complete systems for different parts of your house.)

The SMA battery inverter solution seems to always require support equipment. Some other brands may have an all-in-one system. I'm happy with my SMA for now, spent fairly big bucks, but got as much as I did on account of the bargains out there. (back when I bought my first SI5048 for $5k I wasn't going to install 4 of them.)
 
Hedges said:
SI6048 is quite good. The issue I ran into was a functionality of SB 10000TLUS-12, which didn't respond properly to RS-485 signalling. It does work properly with off-grid a.k.a. island mode.

SMA's latest Sunny Boy, the series that includes. the 7.7 kW -40 and -41 models, doesn't have an RS-485 adapter available. It does have the off-grid mode.
Click to expand...

I'll need RS-485 since I plan to use Batrium BMS with my battery system.

Hedges said:
SMA is now telling me the thing to do is use off-grid setting with Sunny Island, even if for grid-backup and not strictly off-grid. It does work; I just challenged them on that because SMA Germany previously published documents saying to use UL1741 settings (not off-grid) for inverters without backup option.

With Si6048 you'll either need a 120V/240V transformer or else two (or four) Si6048 to produce split phase. You also want a load-shed relay to disconnect the house in case of low battery while keeping Sunny Boy on line.

That's all assuming a grid-backup setup. For off-grid, you can use a different brand charge controller and a shunt.
Click to expand...

Yep :) I planned for dual SI6048 with a current shunt + contactor/relay disconnect for the battery bank.

Hedges said:
It may be that The Sunny Island 8.0 currently being sold in Europe will come here. It uses a different bus (speedwire maybe?) that the new Sunny Boys do support.
Click to expand...

I've heard rumor the a new version for Europe will come to the US but they are waiting to empty existing stock.

Hedges said:
There is also Sunny Boy Storage which works only with high voltage lithium batteries, and does talk to the new Sunny Boys. As a backup system, it requires a separate box providing transfer switch and 120V/240V transformer. Only a single 6 kW Sunny Boy Storage can be used (but you could have multiple complete systems for different parts of your house.)

The SMA battery inverter solution seems to always require support equipment. Some other brands may have an all-in-one system. I'm happy with my SMA for now, spent fairly big bucks, but got as much as I did on account of the bargains out there. (back when I bought my first SI5048 for $5k I wasn't going to install 4 of them.)
Click to expand...

They're preferred battery systems are expensive and multiple segments sounds overly complicated. My DIY system is based off existing builds and the Powerwall design. Please share feedback here: https://diysolarforum.com/threads/planned-on-grid-solar-system-with-battery-backup.7638/

No doubt SMA has high quality components and hardware but the software leaves much to be desired. Sol-Ark seems to check all the boxes and for around the same price as two SI6048 one 12kW Sol-Ark includes everything and has charge controllers!

The SMA's seem battle tested, I'm waiting for more info/reviews on the Sol-Ark since it would greatly simplify wiring and setup but I haven't heard any long term reviews.
 
From everything I have read if you want to use a SMA as a hybrid inverter to AC couple to a GT inverter that they are not there yet. Of course to be UL 1747 compliant they have to be able to be controlled by frequency but any low cost GT inverter can do that. It actually took Outback over a year to get the Skybox to be able to control a grid tie inverter with AC coupling and I can say they did a good job once the firmware got updated. That is a market the Tesla Powerwall is going to share exclusively with Outback, SolArk annd others if SMA doesn't get their ducks in order.
 
Ampster said:
... if you want to use a SMA as a hybrid inverter to AC couple to a GT inverter that they are not there yet...
Click to expand...

I'd like to hear details about that. I think it works fine with a GT inverter designed to throttle production.

The original UL1741 had inverter drop off if frequency outside 59.3 to 60.5 Hz:

1591900574312.png

The SMA inverters with "backup" or "offgrid" settings have default frequency limits that derate output from 100% at 61 Hz to 0% at 62 Hz:

1591900655926.png

Sunny Island runs frequency up gradually to request reduced output. Later, it reduces frequency to about 58 Hz to correct accumulated error in clocks/timers. This works nicely with Sunny Boy that follow the above behavior. My 10000TLUS-12 didn't do that on "backup" setting but it did on "offgrid". The Sunny Island still provides disconnection from grid according to UL1741 but leaves its output side powered up.

If used with a standard UL1741 inverter like my older SWR 2500U, instead of gradually decreasing output that inverter completely drops off at 60.5 Hz. It waits 5 minutes before reconnecting, during which Sunny Island provides all the power from batteries.

Problem is Sunny Island drops to 58 Hz and so the standard UL1741 inverter doesn't reconnect until the frequency is later raised back to 60 Hz.

Solution in that case is to change lower limit frequency setting of Sunny Island.

But it still isn't elegant because the standard UL1741 inverter puts out all or nothing, and batteries cycle.

I don't see how any other battery inverter could do a better job of that.
But a "Dump Load" programmed to linearly increase heating of a water tank from 0% at 60.1 Hz to 100% at 60.4 Hz might make it work.
 
How best to watch SI6048's with no webbox? Victron smart shunt? BMS with supporting interface?
 
Picasso said:
How best to watch SI6048's with no webbox? Victron smart shunt? BMS with supporting interface?
Click to expand...

Presently I'm just not doing it, except hitting a button and looking at power export to grid.
Can also pull out SD card to get historical data.

Here are a couple SMA links on communication software for developers:


YASDI

The software YASDI is suitable for the development of individual applications for the communication with SMA products - See more at: http://www.sma.de/en/products/monitoring-control/yasdi.html#sthash.V4DVkGjz.dpuf
www.sma.de

Maybe somebody has written code for a PC to monitor, but I haven't looked further.

I have Sunny Boy Control, which uses RS-485. It can talk on a bus with Sunny Island connected, but doesn't recognize SI6048. It recognizes SWR2500U but not 10000TLUS. If I could get that working will all my Sunny Boys that would be a good status report.

SMA Com Gateway should be able to do it:


And finally, each SI6048 has two relays. All in a system can be programmed, so you can at least have a few digital indications (on/off grid, full batt, etc.)
 
Hedges said:
With Si6048 you'll either need a 120V/240V transformer or else two (or four) Si6048 to produce split phase. You also want a load-shed relay to disconnect the house in case of low battery while keeping Sunny Boy on line.
Click to expand...

I can't tell you how many times my battery has emptied out at night and left me pulling my hair in the sun the next day. It never occurred to me to use a load shed relay...

Now off to research how to wire it in.
 
YellowBuddy said:
I can't tell you how many times my battery has emptied out at night and left me pulling my hair in the sun the next day. It never occurred to me to use a load shed relay...

Now off to research how to wire it in.
Click to expand...

Assuming you have a Sunny Island, Right there on page 60:

"Default settings of the relays
Relay 1 is preset to the "AutoGn" generator start function and relay 2 to the "AutoLodSoc" load
shedding function."

As another poster said, 300 pages of German instructions and not one picture of a girl.

The relay has NO and NC contacts. The "normally" position (with Sunny Island off or unpowered) has the load shed. Under normal operation with decent charge remaining on battery, the NO contact of relay 2, which by default is "load shed", gets closed and can control a relay. At default 70% DoD it sheds the load. I finally located the SMA version of a power relay. It is 3PST, 100A per contact, and has 48V coil. I had it shipped from Europe.

(almost) any relay can be used. The relays in SI can handle AC or DC for pilot duty. SI has a 48V (actually battery voltage) terminal available, with 0.5A PTC fuse. The big power relays you will find take WAY more than 0.5A, and the SMA version is no different. At least one I checked (if not the SMA) had a 10 ohm coil. That draws 5A! 250W! but only for milliseconds; as soon as it closes a fourth contact opens. The relay has two windings for the coil, second one being very high resistance for "hold" but not "pull in". The fourth contact switches the coils before PTC fuse opens, so current draw greatly reduced.


 
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