Sunny Island SI-6048 with Sunny Boy 8000-US, RS485 vs. UL 1741

[kommando]

On my Solax I did the changes to follow the SI on the Solax.

The two parameters that need adjusting are

FreqSetPoint (Htz)

and

FreqDropRate (%)

So for a Sunny Island these would be set to 51Htz and 10% so that by 52Htz the output is zero. ( UK is 50htz mains supply)

You also have to set the Grid country to one that supports these parameters, eg EN50438_NL, VDE4105 or User Defined

and also play around with parameters to improve stability

Fac Upper and Fac Upper slow

 

[duerrd561]

There is no mode. It phase shifts out of the box. But after a number of seconds above 60.5 hz, it would shut down. I had to adjust the settings to get 100% control below 60.5 hz so it never shuts down. It starts throttling at 60.04 hz and is down to zero without shutting down usually around 60.42hz

I admittedly never took the time to tune *any* of this behavior, despite having a "tuner" mentality on computer networks, etc. But re-reading your comment here has me thinking that tuning things like this might also be able to mitigate some of the flickering behavior I was mentioning on my old Insteon dimmers (which makes them unusable during this time). I am thinking that the default settings might have a wider band of frequencies, where I could tighten it down like you mention here.

 

[1201]

Got it, thanks. This seems to line up with even SMA's own products more recently, where they claim to enable "grid-backup" behavior by default now, right out of the box. I suspect they got tired of everyone asking for "grid guard" codes?

Where did you have to make the settings adjustments you mentioned? In the Sunny Island, or in the Growatt?

I made one change in the growatt. Sunny island just keeps raising the frequency until it gets the output it needs. No settings to change on sunny island

 

[Hedges]

Thank you for the correction. I was going off memory, and had them backwards. I've corrected the original post above.



The ATS does not have a 5 second "off" time when it switches -- I'd say it's about a 500ms switch time from grid to generator, and a 250ms switch time from generator back to grid. Slow enough to kill power to computers, or to reset the oven clock. But it also has a 5-minute delay for grid stabilization before switching from generator back to grid, and when this process is occurring the Sunny Island has independently seen the return of grid power on AC2 and presumably gone through some sort of process to resync itself with that frequency such that when the 5-minute switchover occurs, you generally don't notice it happened.

Only if breaker feeding SI AC2 is on.
If it is off, would not be sync'd and could blow up SB when input phase jumps. Its FETs could be fighting the grid. At least in theory, based on SMA's warnings.

One guy did put SI AC1 output across the grid and it simply tripped breakers. That was at the end of a long wire.

I apologize, but I am not sure. My primary residence is not at the house, and I cannot get the specific model suffix from the portal on the device. I bought it in 2016, and I have a hunch it is the -40 since it is running (and maxes out at) an older firmware version. It looks like it is set to Island Mode 60Hz. The other options available in the picklist are Default, HECO2017, UL1741/2016, and WorstCase.

I think newer firmware allows Rule 21.

You're switching this direct onto grid? Island mode would not have anti-islanding. It would have wider voltage and frequency settings.
This defeats some of the lineman safety requirements. (conditions needed for it to backfeed a dead line aren't likely to be achieved, but UL-1741 is what is approved for safety.)

Got it. So I think what you're saying is that the SB 8000-US *requires* RS485 to properly work with the Sunny Island in "grid-backup" mode. In other words, I would not have been able to make this older inverter work without RS485. Did I understand that correctly?

Correct, regarding backup mode. Without RS-485 it would remain UL-1741.

It would work in offgrid/island mode. But would not perform anti-islanding. SI would perform anti-islanding. I avoid relying on that, based on what SMA Germany engineers documented (and reports of relays welding shut.)

Fascinating. And scary thought about the relay welding shut, but it makes sense that the possibility exists.

So I figure SMA Germany came up with this during FMEA, deal with it by SI recognizing relay is stuck and telling SB via RS-485 do its own UL-1741 anti-islanding.

I don't trust a different recommendation (from SMA America) if they don't acknowledge the previous written instructions, explain why not applicable, and put that in writing.

It shows "Disturbance VacL1-Bfr". It's been running alongside the SB 5.0 and the Sunny Islands, in the configuration described above, for ~8 years with no issues. It's hard to imagine that it is suddenly being disturbed by the SB 5.0, now.

I think Bfr is frequency; does it quote the frequency observed?
I think mine do. Could occur during dropped power, not just frequency shift (knock offline by going above 64 Hz prior to synchronizing (only if excess production, was above 60 Hz before trying to reconnect.)

Try measuring voltage and frequency.

Perhaps line impedance is different and more noise from SB 5.0 is seen. I haven't checked waveforms from my -41 yet.

I did see poor PF from a VFD upset a SB. Documents say if that error continues, it becomes locked. I was playing with SBS during a grid failure, connected to SI, and discovered my SunPower SB 8000US locked that error, is now bricked. I suspect but don't know SBS current waveform did that.

Yes, I tried this route. Unfortunately the guys who do this don't have SB 8000-US anymore. And I'm just not super interested in riding the SMA train here given the high cost and what I'd argue is a questionable product management strategy.

A bunch of SB show up on Craigslist and eBay. Of course they do eventually wear out, maybe after 20 +/- years, so I prefer low mileage or NOS.

I like to pay $0.10/W, preferably for unused ones.

Be aware some models are 208V only, SB 10000TL-US-10 I think. -12 is 240V (also has AFCI) 10000TL-US-12 does not support backup (I informed SMA, they confirmed and changed compatibility list.)

Interesting. So you're a fellow SunPower user? Did your modules claim to not require positive grounding like mine? Tigo's web site talks about a new device they are working on incorporating which goes between the array strings and the inverter and helps mitigate PID. It looked promising, but not yet available for sale.

I learned about PID some time after getting the SunPower 327W panels. Their data sheet, also the REC and Qcells I plan to use at a new place, claim zero or low PID.

For a year I ran SunPower 327W, AstroPower 120W, Sharp 165W polycrystaline, all in parallel and ungrounded transformerless. Later discovered some Sharp were degraded, don't know if due to that. That model is known for it.

SMA for a while had a bias box to bias string at night to partially reverse PID.
Panel chemistry has been changed to be resistant.
I plan to use SB 5000US series to bias positive or negative as desired, even if low PID.

It appears to be their latest comm bus that interconnects all their competing communication protocols. I am honestly not super impressed with the number of variants they've created in the first place. Hence, combined with the high price tag, my lack of interest in supporting their latest variant.

Monitoring SB isn't so important. Drop in system output, check the displays, use a clamp DC ammeter to check individual strings.

SB -41 with WiFi or SpeedWire, you should be able to hook up and read.


I'm sticking mostly with old stuff, but trying some newer products when they show up cheap on eBay just because. And need recent grid-support features for new system installs and permission to operate.

Thanks again for your detailed responses here.

I have concerns about SB -41 together with SB 5000US on SI, that bad waveforms could upset or brick the other. Don't know if that is a problem.

Rule-21 would let you switch between direct to grid and being on SI.
Backup mode, if I switch, I figure I need to switch RS-485 so when direct on grid it isn't told by SI to be offgrid.

If I was you I would consider getting multiple SB of the 5000 ... 8000 series and use just those. 8kW + 5kW = 13kW is OK going through 2x SI so would put both on protected loads panel. (I considered switching additional SB to support twice as much PV.) It may be better not to have anti-islanding by SB when SI forms island (not sure if a problem or not.)

I certainly recommend not using offgrid/island mode for an inverter direct on grid. Not compliant and my be a lineman safety hazard.

If you use Rule-21, consider adjusting frequency limits for disconnect and/or frequency/watts settings of SB 5000US so they work together better without anyone getting knocked offline. This is 15+ years of products being made to work together. SMA invented frequency-watts long before the grid asked for Rule-21 and grid support.

Got it, thanks. This seems to line up with even SMA's own products more recently, where they claim to enable "grid-backup" behavior by default now, right out of the box. I suspect they got tired of everyone asking for "grid guard" codes?

You would think.

But more than that, if off-grid and frequency of SI is sitting outside UL-1741 range, the SB 5000US series wouldn't connect and feed in, during which time it wouldn't talk on RS-485 so you couldn't change its mode.

I saw that, threw the grid switch, then it connected and I could put it in backup mode.

No harm in having backup enabled anyway, so better that they made the change.

 

[1201]

I admittedly never took the time to tune *any* of this behavior, despite having a "tuner" mentality on computer networks, etc. But re-reading your comment here has me thinking that tuning things like this might also be able to mitigate some of the flickering behavior I was mentioning on my old Insteon dimmers (which makes them unusable during this time). I am thinking that the default settings might have a wider band of frequencies, where I could tighten it down like you mention here.

My dimmers have a hell of a time on sunny island even if it's not phase shifting.

It's related to my fridge somehow. When it's running the flickering happens -when the compressor stops, no flickering

 

[duerrd561]

Only if breaker feeding SI AC2 is on.
If it is off, would not be sync'd and could blow up SB when input phase jumps. Its FETs could be fighting the grid. At least in theory, based on SMA's warnings.

One guy did put SI AC1 output across the grid and it simply tripped breakers. That was at the end of a long wire.

Yikes. But yeah, the breaker feeding SI AC2 is always on so long as something doesn't trip it. I've never had it trip in ~8 years of operation (knocking on wood), but I get your point here and its something to be aware of.

I think newer firmware allows Rule 21.

You're switching this direct onto grid? Island mode would not have anti-islanding. It would have wider voltage and frequency settings.
This defeats some of the lineman safety requirements. (conditions needed for it to backfeed a dead line aren't likely to be achieved, but UL-1741 is what is approved for safety.)

The SB 5.0 is wired in to a panel sitting behind the ATS, so my rationale here was that the ATS would essentially provide anti-islanding between the SB 5.0 and the grid. And on several occasions I've witnessed the scenario where we have an extended off-grid situation and accidentally deplete the batteries on the SI below the 40% SoC cutoff such that the load-shedding contactor is opened and the generator input to the ATS goes dark. Then the sun comes up and the solar panels start to produce. The SB 8000-US coupled to AC1 is running and feeding power back into the SI, recharging the batteries. But the SB 5.0 doesn't start outputting any power on the AC side until the SI re-engages the contactor and allows AC1 power to reach the generator input of the ATS, at which point the SB 5.0 then comes online.

Correct, regarding backup mode. Without RS-485 it would remain UL-1741.

It would work in offgrid/island mode. But would not perform anti-islanding. SI would perform anti-islanding. I avoid relying on that, based on what SMA Germany engineers documented (and reports of relays welding shut.)

Got it. Thanks.

I think Bfr is frequency; does it quote the frequency observed?
I think mine do. Could occur during dropped power, not just frequency shift (knock offline by going above 64 Hz prior to synchronizing (only if excess production, was above 60 Hz before trying to reconnect.)

Try measuring voltage and frequency.

Perhaps line impedance is different and more noise from SB 5.0 is seen. I haven't checked waveforms from my -41 yet.

I did see poor PF from a VFD upset a SB. Documents say if that error continues, it becomes locked. I was playing with SBS during a grid failure, connected to SI, and discovered my SunPower SB 8000US locked that error, is now bricked. I suspect but don't know SBS current waveform did that.

Unfortunately it doesn't show frequency. But it does show a voltage readying which shows 129V on the L1 leg. I believe there is a ~1s tolerance for voltage above 129.3V at which point the SB 8000-US would see a disturbance. At least this was what I read in the manual.

Monitoring SB isn't so important. Drop in system output, check the displays, use a clamp DC ammeter to check individual strings.

SB -41 with WiFi or SpeedWire, you should be able to hook up and read.

I agree. Once I found myself with 2 generations of SB technology that couldn't even talk to each other, let alone (reliably) to my Home Assistant system without me doing my own integration development (which I can do, but don't have time to with day job and life responsibilities), I rolled my own monitoring system using Shelly EMs + CTs for solar production monitoring and Shelly I4s for SI relay reporting. We live across the country now, and PG&Es rates only continue to go up, so monitoring the system is key to avoid huge PG&E surprise bills.

I'm sticking mostly with old stuff, but trying some newer products when they show up cheap on eBay just because. And need recent grid-support features for new system installs and permission to operate.

If I was you I would consider getting multiple SB of the 5000 ... 8000 series and use just those. 8kW + 5kW = 13kW is OK going through 2x SI so would put both on protected loads panel. (I considered switching additional SB to support twice as much PV.) It may be better not to have anti-islanding by SB when SI forms island (not sure if a problem or not.)

I *really* appreciate your suggestion, and respect where you're coming from. If I lived at the property full time as I used to, I'd likely go this same route as I'd be able to rewire the secondary inverter like you say, to source the used SB 8000-US, and to closely monitor things. Unfortunately now that I live across the country, I'm unable to be as hands-on with things and I'm stuck hiring electricians, etc. when things go wrong. I just need something reliable that works, is under warranty, etc. We run an Airbnb out of the house when we're not there so taking a 50% hit on solar generation as we are now really affects the bottom line, hence the need to make this a straightforward and inexpensive replacement that my original installer can do without me there.

If you use Rule-21, consider adjusting frequency limits for disconnect and/or frequency/watts settings of SB 5000US so they work together better without anyone getting knocked offline. This is 15+ years of products being made to work together. SMA invented frequency-watts long before the grid asked for Rule-21 and grid support.

I will likely have the old SB 8000-US available if anyone has interest in it.

 

[duerrd561]

My dimmers have a hell of a time on sunny island even if it's not phase shifting.

It's related to my fridge somehow. When it's running the flickering happens -when the compressor stops, no flickering

Yeah, the Insteon dimmers are triac dimmers and can be sensitive when we're overproducing power in an off-grid situation. Otherwise they've actually been pretty good. But with Insteon, you have the added complexity of powerline communication which relies on the 60.0Hz zero crossing for signal transmission. They also use wireless 900MHz as a secondary communication route, but for really long runs the powerline mode saves the hassle of repeaters. All that said, Insteon is basically gone now so I've been migrating to Z-Wave Plus and Shelly devices which work really well.

 

[Hedges]

Unfortunately it doesn't show frequency. But it does show a voltage readying which shows 129V on the L1 leg. I believe there is a ~1s tolerance for voltage above 129.3V at which point the SB 8000-US would see a disturbance. At least this was what I read in the manual.

If voltage or frequency is near its limits, you could relax those a bit.
I did that for frequency, increasing UL-1741 setting to what UL-1741 SA allows (without feeling guilty).
If raising voltage outside spec that would technically be wrong ...

I will likely have the old SB 8000-US available if anyone has interest in it.

I might be. Although not a great need, have plenty of new in the box 5000-US stored.
But how old? They do eventually die. Shipping by freight is expensive. Where in California?

 

[duerrd561]

If voltage or frequency is near its limits, you could relax those a bit.
I did that for frequency, increasing UL-1741 setting to what UL-1741 SA allows (without feeling guilty).
If raising voltage outside spec that would technically be wrong ...

Interesting. Did you make your frequency adjustments in the SB using the WebBox? If nothing else, this might help me get a little more time out of the SB 8000-US before it dies. Today it seems like its more sensitive than it used to be, and thus is going intermittently into disturbance mode.

I might be. Although not a great need, have plenty of new in the box 5000-US stored.
But how old? They do eventually die. Shipping by freight is expensive. Where in California?

Got it. The house is near Salinas, California and the SB 8000-US was put into service in mid-2012.

 

[Hedges]

For it to be more sensitive would mean drift in voltage/timing of ADC measurements. Or an analog filter, which I would guess is solid dielectric, not electrolytic. So I'm guessing not.

More likely is grid has changed. So tweaking settings could let it continue indefinitely.

I did it with Web Box. Previously I used Sunny Boy Control. I have a TriPower which didn't communicate over RS-485, does over SpeedWire so I used Sunny Explorer free software. Supposedly TriPower has Rule-21, but not shown by name. Already had frequency-watts; I just had to widen frequency window from UL-1741 to make that work.

You will need Grid Guard, also installer password. You can get PUK, which actually isn't "personal", rather for a given serial number, to reset password.

A decade is aged, hopefully good for 20 years or more. Out of 5 earlier models I had 2 failures in 17 years, 3 had not failed.

Close enough I would drive from San Jose to pick it up.
If you sold it cheap. I paid $0.10/W (sometimes less) for brand new units.
I've picked up a couple newer models that were second hand for $0.05/W

If you can adjust it work, obviously the most cost-effective for you.

Do you have some time of use load control to dissuade your renters from using on-peak power?

 

[duerrd561]

Thanks to everyone here for the really informative responses, I think I finally understand how this all works. I'd like to try and summarize, and see if you all agree. My original question was this:

So, what functionality am I gaining by having the older Sunny Boy 8000-US and the Sunny Island connected via RS485, beyond the ability to monitor and/or configure them via the WebBox?

When the SI forms an island (i.e. goes off grid), it sends a signal out on the RS485 bus to inform connected SB inverter(s) that they may switch to the "OffGrid" setting as the SI is performing the anti-islanding function. In the absence of this signal, the SB inverter(s) will default to "grid tied" setting and will be responsible for performing their own anti-islanding function.

Separately, the SI will increase the frequency (i.e. phase shift) on its AC1 circuit to alert any generating PV inverters that they need to reduce their production, and this frequency shift will step along a curve to partially or fully reduce that generation. The same SB inverters that might be connected to RS485 as described previously will use this signal to change their production, or possible turn off. But even in the absence of the RS485 connection, any inverter that sees this phase shifting behavior will derate its output accordingly.

Meanwhile, the newer standards introduced through UL 1741-SA/SB, Rule 21, etc. have essentially delivered PV inverters that do not need the signal being sent by the SI because they already support a broader/newer standard which supports equivalent operation of when the older SB has been switched to the "OffGrid" setting, and they do so out-of-the-box. And they also support the phase shifting functionality as a mechanism to throttle down production *when* they are generating off-grid power.

So in summary, the newer inverters and standards don't need the signal from the SI over RS485 to do the things I'd want them to do. But if I were to replace the current SB 8000-US with another SB 8000-US, for example, then I would need RS485 to maintain functionality.

Did I basically get this right?

 

[1201]

Thanks to everyone here for the really informative responses, I think I finally understand how this all works. I'd like to try and summarize, and see if you all agree. My original question was this:



When the SI forms an island (i.e. goes off grid), it sends a signal out on the RS485 bus to inform connected SB inverter(s) that they may switch to the "OffGrid" setting as the SI is performing the anti-islanding function. In the absence of this signal, the SB inverter(s) will default to "grid tied" setting and will be responsible for performing their own anti-islanding function.

Separately, the SI will increase the frequency (i.e. phase shift) on its AC1 circuit to alert any generating PV inverters that they need to reduce their production, and this frequency shift will step along a curve to partially or fully reduce that generation. The same SB inverters that might be connected to RS485 as described previously will use this signal to change their production, or possible turn off. But even in the absence of the RS485 connection, any inverter that sees this phase shifting behavior will derate its output accordingly.

Meanwhile, the newer standards introduced through UL 1741-SA/SB, Rule 21, etc. have essentially delivered PV inverters that do not need the signal being sent by the SI because they already support a broader/newer standard which supports equivalent operation of when the older SB has been switched to the "OffGrid" setting, and they do so out-of-the-box. And they also support the phase shifting functionality as a mechanism to throttle down production *when* they are generating off-grid power.

So in summary, the newer inverters and standards don't need the signal from the SI over RS485 to do the things I'd want them to do. But if I were to replace the current SB 8000-US with another SB 8000-US, for example, then I would need RS485 to maintain functionality.

Did I basically get this right?

Basically right but frequency shifting does not only happen off grid. The grid can use frequency shifting to reduce solar output if they want to, by raising the frequency of the grid and the inverters will throttle output as commanded.

 

[Hedges]

Basically. Except:

SB 8000-US won't ramp down production if in UL-1741 mode (e.g. backup mode but no RS-485). It will shut off at 60.5 Hz, wait 5 minutes to reconnect.

SB -41 series will not do Rule-21 out of the box. It will likely default to UL 1741 SA, with over-voltage and over-frequency allowing full output but for limited time of ride-through. Have to set Rule 21. May need to update firmware if older version didn't include that. They do have off-grid (Island) mode.

Basically right but frequency shifting does not only happen off grid. The grid can use frequency shifting to reduce solar output if they want to, by raising the frequency of the grid and the inverters will throttle output as commanded.

Which would mean a frequency shift for the entire Western half of the United States. Including places with excess PV and places with inadequate power distribution. So I wonder why it was ever implemented. Volts-watts seems more useful. Apparently Volt-Var lets systems export more without driving voltage too high (but could still give grid too much power.)

 

[duerrd561]

I agree it's an outlandish concept for them to shut down PV production in the entire half of the continent, though I wouldn't put it past PG&E to try something nefarious like this. Good call out. Next we'll need firewalls for this.

The bottom line as I see it now is that I won't lose any critical off-grid functionality if I replace the SB 8000-US with a newer inverter like the Growatt MIN 7600 XH-US mentioned above, so long as the replacement inverter supports these newer "grid backup" standards. And in this case, there is obviously no use for the RS485 connection. On the flip side, should I replace the SB 8000-US with an inverter in its same generation (i.e. SB 3000-US, 5000-US, 6000-US, etc.) then the RS485 is absolutely critical to having it function like mine does today. This all makes sense to me.

 

[SilverbackMP]

If you are looking for 7.7s, don’t be me:

Major Problems with Solar Cellz USA - No Product and No Refund

This will be a long one. Multiple Posts to follow. TLDR: Ordered six Sunny Boy inverters from Solar Cellz USA September 1st 2023. One was eventually delivered via FEDEX. Series of excuses and promises of refund (which never materialized) followed. Bottom line - out $11,528.36 including five...

diysolarforum.com

I did just get a fifth one from that order today.

If I get all six, I’ll have 8 spares and for future expansion (both the current system and new one but likely using Victron for the inverter as I am now sour).

 

[duerrd561]

If you are looking for 7.7s, don’t be me:

Major Problems with Solar Cellz USA - No Product and No Refund

This will be a long one. Multiple Posts to follow. TLDR: Ordered six Sunny Boy inverters from Solar Cellz USA September 1st 2023. One was eventually delivered via FEDEX. Series of excuses and promises of refund (which never materialized) followed. Bottom line - out $11,528.36 including five...

diysolarforum.com

I did just get a fifth one from that order today.

If I get all six, I’ll have 8 spares and for future expansion (both the current system and new one but likely using Victron for the inverter as I am now sour).

Thanks for the warning, and ouch -- sorry for the hassle there. Honestly, my loyalty to SMA has dwindled over the last 10 years with all the product line changes, communication protocol changes, etc. I'm really excited to hear that I at least have the option to move to something else and am not forced to stay on the SMA train.

 

[Hedges]

I'm happy to be a 100% SMA shop. Not happy to be forced to newer models by NEC and utility grid-support features. Happy that lots of great old SMA equipment has been obsoleted so I can pick it up for $0.25 on the dollar.

The old stuff also doesn't have the time shifting I might want to game utility rates meant to shift balance of power back to PG&E.

And California's plan to bill me for electric service based on income not usage makes me want to join the underground economy. "It's not easy being rich, I mean green."


Besides Blue, also consider Black.
Midnight has brought out some new inverters, and of course those guys are really good.

 

[1201]

I'm happy to be a 100% SMA shop. Not happy to be forced to newer models by NEC and utility grid-support features. Happy that lots of great old SMA equipment has been obsoleted so I can pick it up for $0.25 on the dollar.

The old stuff also doesn't have the time shifting I might want to game utility rates meant to shift balance of power back to PG&E.

And California's plan to bill me for electric service based on income not usage makes me want to join the underground economy. "It's not easy being rich, I mean green."


Besides Blue, also consider Black.
Midnight has brought out some new inverters, and of course those guys are really good.

I successfully sold back from battery to grid at night using the webbox "fedin" mode but the sunny island disconnected after a few minutes. The longest I was able to sell back from battery was 8 minutes. I stopped trying so I don't kill anything

 

[Hedges]

Try commanding a reduced battery voltage.
That should be equivalent to manual's description of DC coupled SCC pushing voltage above SI setpoint.

 

[1201]

Try commanding a reduced battery voltage.
That should be equivalent to manual's description of DC coupled SCC pushing voltage above SI setpoint.

I've seen that work too but not able to set the amp rate afaik.my boost is set to 56.6v for two hours. During the day when I have solar I notice that after two hours the inverter will discharge from battery to grid to get the battery voltage down to the float voltage.