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

[YellowBuddy]

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.

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Ftse3.mm.bing.net%2Fth%3Fid%3DOIP._J6xdqndcuc_E1khJ_QS5wAAAA%26pid%3DApi&f=1

https://www.pvxchange.com/en/accessories/_item/abb-load-shedding-contactor-si-ls100-48-5000013-1

Oh the SI is the easy part. I'm more thinking about how to setup the panel. Right now my SB and SI combine in the same panel - my critical loads panel. So to add a load shed, I'd need to wire the relay in before the loads - and space is tight. Hence why the figure out the wiring. I've got a combiner panel for my (2) SB's, so that will most likely be the place to relocate the SI breaker to the combiner.

 

[Hedges]

Oh the SI is the easy part. I'm more thinking about how to setup the panel. Right now my SB and SI combine in the same panel - my critical loads panel. So to add a load shed, I'd need to wire the relay in before the loads - and space is tight. Hence why the figure out the wiring. I've got a combiner panel for my (2) SB's, so that will most likely be the place to relocate the SI breaker to the combiner.

Something like that. Maybe just DIN fuse holders or breakers, not a full panel.
I am using a full panel for several Sunny Boy. But I managed to put two 2-pole 63A DIN breakers inside a Square D 100A fused disconnect, so my four SI6048 have separate breakers for each. Hard part for me was finding the right 3R box for the relay. I had bought a big relay elsewhere that needed a larger box. But it looks like the SMA version of load-shed relay would fit in the top area of a 200A Square D breaker panel.

 

[Picasso]

I never got why one would load shed. In the sense of what do people put on them? Are some users just ok with 1/2 the plugs not working or just like OK the ceilings fans are off now because of batt lvl. Was it just from a time when we didnt have tons of excess solar and fast charging batts? I dump my solar because I need more storage!

 

[Hedges]

I never got why one would load shed. In the sense of what do people put on them? Are some users just ok with 1/2 the plugs not working or just like OK the ceilings fans are off now because of batt lvl. Was it just from a time when we didnt have tons of excess solar and fast charging batts? I dump my solar because I need more storage!

There is a particular reason to load-shed all loads in an AC coupled system:
Batteries power Sunny Island, which produces AC and has a battery charger powered by the same AC.
Sunny Boy is attached to Sunny Island and turns PV into AC. If grid connected, all power not used locally goes to the grid. While off grid, that extra power charges battery through Sunny Island.
If my loads (entire house) run the battery down to low voltage disconnect, Sunny Island shuts off to prevent further discharge. Now, no AC so Sunny Boy stops converting PV to AC and the batteries don't get charged. If at night, even when the sun comes up, battery still low, no AC, no charging.

Two solutions:
1) DC coupled charging (e.g. PV and charge controller)
2) Load-shed relay to disconnect house, leaving enough charge in the battery to last until sunup.
Default setting for lead-acid AGM is shed loads at 70% DoD, wait until back up to 50% DoD before reconnecting.

Of course, additional signals can be used to disconnect heavy loads like air conditioning and laundry sooner, so balance of house stays up.

I have a huge PV array but tiny battery, because batteries are so expensive and mine is only there to make a grid so GT inverters can run my house during the rare power failure. I could recharge from 70% DoD to 100% with the power I make from PV. So I just charge gradually and dump solar during that time.

 

[YellowBuddy]

I never got why one would load shed. In the sense of what do people put on them? Are some users just ok with 1/2 the plugs not working or just like OK the ceilings fans are off now because of batt lvl. Was it just from a time when we didnt have tons of excess solar and fast charging batts? I dump my solar because I need more storage!

It saves a lot of money on battery costs. Without load shedding, my options would be to deal with a critical loads panel that either doesn't support everything (me currently) or I would need about a 150-200kwh battery bank. With load shed, I would be pretty comfortable on a 30kwh battery bank.

For me if my power goes out, the first thing I'd want to shed is my electric vehicles. If those are charging, they'll drain my backup battery in a heartbeat. But if the sun is out, then absolutely I want them topped off. My AC/heat pumps is a big draw and could empty my battery bank in 15 minutes instead of 6 hours; but it can run for 8 straight hours if the sun is out. Once the sun is gone, it's a race to turn it off.

Just a week ago I was too slow to shut off the AC; the panels got shaded from clouds and it went empty in 20 minutes and went into deep discharge mode. I had to hook up my portable generator to restart the sunny islands; by then it was night and I was left on generator power all night. If it had shed the load on it's own, I would have had batteries that lasted through the night and until the sun came back.

 

[GXMnow]

This is one of the situations I was thinking about in my system design.

I am starting out with just a 17 KwH battery bank. While the grid is up it is plenty to store my excess production and move it to the peak time of use later in the day. Looking at a few days of my production and the So Cal Edison useage charts, my over production ranges from about 5 KwH to juat over 10 KwH's. So 10 KwH is the most I would be time shifting. Typically it will be less as I use a fair bit of my power while the sun is up. But when we do have a grid outage, I want to be sure the system will have enough power to kick off the solar panels when the sun comes up in the morning.

If I was not doing any time of use shifting, I know I would be fine as the essential loads will easily last the night on my 17 KwH of battery. But if I am shifting the full 10 KwH, even from a completely full battery, but then the power fails right as it is pulled down to just 7 KwH remaining, I could run into a problem. I could need 10 hours on battery before there is enough sun to start feeding the loads again. While on grid, my normal overnight running loads pulls just under 1 KW. That would need 10 KwH to make it through the night. Oops. I will have a bit less than that on the essential loads panel, but I think it may still be 700 watts keeping my systems alive during a blackout.

Once I have the battery inverter up and running, I will have to take a few measurements and see if I want to load shed a few items to preserve some battery. I will likely add more battery in the future, but for now, full on power failures are still rare and I do have a generator if I get caught out.

 

[Hedges]

Hi Picasso,
How do I get SI firmware 7.302
I did the upgrade before reading your post

I made an inquiry to service@sma-america.com

"On your web site I find "archive" with software or firmware for older products.
But do you make available older revisions of firmware (or software) for current products?

In particular, some people using Sunny Island 6048US want to roll back to firmware 7.302, and 7.304 appears to be the only one accessible on your web site.
Is 7.302 available for download?"

Reply:

"Yes, it is possible to downgrade the firmware of an inverter, the process being slightly different than an upgrade.
Why do you want to downgrade the inverter ? are you having any compatibility or production issues ?"

follow-up inquiry

"Someone recently updated his to 7.304, but other users who attach lithium batteries (typically home assembled, not with a BMS that talks to Sunny Island) have said 7.302 was best for that application.

Where on your site can the older rev firmware be found?
And what is the slightly different process?"

follow-up reply:

"We will send this information to our Hybrid department, can you please provide the Serial number of your Sunny Island so that we can create a full case."

So you should email your request to service@sma-america.com in order to get the firmware.

 

[Ampster]

This is one of the situations I was thinking about in my system design.
...... .....
Once I have the battery inverter up and running, I will have to take a few measurements and see if I want to load shed a few items to preserve some battery. I will likely add more battery in the future, but for now, full on power failures are still rare and I do have a generator if I get caught out.

You are thinking about the right things. I am in PG&E territory and heading into fire season so I am keeping an eye on how much I have in reserve each morning. Fortunately I can set a minimum SOC and right now it is at 30% and the lowest I have gone is to about 60% SOC.
I don't haveca generator but the outages that come with fire season are usually sunny.

 

[Hedges]

You are thinking about the right things. I am in PG&E territory and heading into fire season so I am keeping an eye on how much I have in reserve each morning. Fortunately I can set a minimum SOC and right now it is at 30% and the lowest I have gone is to about 60% SOC.

... and @GXMnow "but then the power fails right as it is pulled down to just 7 KwH remaining, I could run into a problem. I could need 10 hours on battery before there is enough sun to start feeding the loads again. "

Trouble with that is you end up paying for a lot of extra battery just in case you drain the smaller one doing peak shaving then get hit with a blackout.

If you don't absolutely have to keep things running through the night, you could live in darkness until the first morning after a power outage, then without the grid to peak-shift you'll just run on solar. Recognize an outage and start using power when you make it rather than based on time of use schedules. You just need a way to recover from discharged battery, which our AC coupled systems don't conveniently have, unless we load-shed.

This could be one time you resort to a fossil fuel generator.

 

[GXMnow]

Last year SCE did give us a warning we may get a "Public Safety Power Shut Down". I could change the settings to keep the battery full when we get a warning and just not bother with the time of use shifting for a few days each year. If I am home when we get an unexpected power cut, I can certainly turn off a few more things we don't need until we get the battery back up. And the worst case, if it does hit low battery cut off, I fire up the generator to charge the batteries enough to get the solar back up. 17 KwH "should" be enough in any normal use case.

We have already had 3 fires that were within 5 miles of us this year, but no power cut yet.

 

[YellowBuddy]

Last year SCE did give us a warning we may get a "Public Safety Power Shut Down". I could change the settings to keep the battery full when we get a warning and just not bother with the time of use shifting for a few days each year. If I am home when we get an unexpected power cut, I can certainly turn off a few more things we don't need until we get the battery back up. And the worst case, if it does hit low battery cut off, I fire up the generator to charge the batteries enough to get the solar back up. 17 KwH "should" be enough in any normal use case.

We have already had 3 fires that were within 5 miles of us this year, but no power cut yet.

Since you have a gen, it’s not that much of a worry. But there’s definitely some decent draining still going on there. I only have a fraction of what you have (4.8kWh) To get through the night it’s not automated yet, but I turn off almost everything. The only thing that stays on - bedroom lights, tv, internet. To keep us entertained.

Everything else is flipped off until the sun comes back. I can get roughly 12-13 hours like that and have about 15-20% remaining in the morning so the solar kicks in.

HVAC is the big thing for us, the house is usually good enough to carry a consistent temp through the night in the summer but winter is a challenge if it drops to the single digits.

It’s not a fun way to live, but it might be good to have that oh sit breaker to dump your draws on days you get zero notice. Probably not worth the trouble since you have a generator though...

 

[GXMnow]

My biggest near constant draw is leaving the fan in the furnace running at 20% all day, but it makes the house so much more comfortable. It draws about 3 to 5 amps on a single 120 volt leg (360 to 600 watts), not sure why it varies that much, it is a variable speed inverter motor. In full cool mode it spins up much faster and pulls over 7 amps, but that won't happen when I am in battery mode. In winter, if I have to run heat, it is between there, maybe 6 amps with the draft fan and the gas valves on. The other big draw is my refrigerator/freezer. If I can get my son to leave the door closed, it only runs 10-15 minutes per hour, but it pulls over 300 watts while on. The internet gear and the dish network all together is probably under 100 watts. The one PC we use all the time has a very low power sleep mode, and up to 200 watts if playing videos or light gaming, the graphics card is not up to big gaming. Add another 300 watts when we fire up the older 55 inch LCD TV, it's a power pig by modern standards, but it has a nice picture.

Being in So Cal, my solar panels start making usable power (over 400 watts) as early as 8:00 am. They are still making over 400 watts to about 7 pm also. They peak at over 3400 watts around 1 PM and pump out over 25 KwH on any clear day, topping 30 KwH in spring and fall when it is cooler and the sun angle lines up better. I don't think I will have a problem keeping the battery full once I am in a blackout condition. The Schneider XW-Pro inverter will technically have enough current if we do decide to fire up the A/C for an hour or so off the batteries when it hits 110 F out here. The A/C compressor in high mode pulls up to 14 amps at 240 volts, but has a starting surge of over 40 amps. The XW can pump out 12,000 watts for 30 seconds, and 6,800 watts continuous. I would most likely only run it at full sun so the power would mostly be from the solar panels. I may also power the outlet for the microwave oven, at 1,100 watts. Everything else I would run during a power failure is small. The stove is gas with an electronic igniter. Even my washer and dryer pull less than 5 amps each, with the dryer being gas heat. My bigger concern would be if we have an earthquake that knocks out the gas and/or water lines. My house has survived 3 major quakes, but you never know. I am far from a prepper, but being prudent is not a bad idea.

 

[manmont]

I made an inquiry to service@sma-america.com

"On your web site I find "archive" with software or firmware for older products.
But do you make available older revisions of firmware (or software) for current products?

In particular, some people using Sunny Island 6048US want to roll back to firmware 7.302, and 7.304 appears to be the only one accessible on your web site.
Is 7.302 available for download?"

Reply:

"Yes, it is possible to downgrade the firmware of an inverter, the process being slightly different than an upgrade.
Why do you want to downgrade the inverter ? are you having any compatibility or production issues ?"

follow-up inquiry

"Someone recently updated his to 7.304, but other users who attach lithium batteries (typically home assembled, not with a BMS that talks to Sunny Island) have said 7.302 was best for that application.

Where on your site can the older rev firmware be found?
And what is the slightly different process?"

follow-up reply:

"We will send this information to our Hybrid department, can you please provide the Serial number of your Sunny Island so that we can create a full case."

So you should email your request to service@sma-america.com in order to get the firmware.

Thank you Picasso

 

[manmont]

Thank you Picasso

 

[Hedges]

I think I'm seeing an issue with frequency shift power reduction of a different model Sunny Boy, the 5000US.

I switched off AC input to Sunny Island for some work on my electrical boxes. This is equivalent to having a power failure. Sunny Island took over providing island grid, and 5000US which is configured for "backup" and has RS-485 connected switched from grid-connected to backup mode. Power output was reduced to match load as desired, and frequency was between 61 Hz ands 62 Hz.

My Sunny Island has default configuration where it also spends time below 60 Hz, down around 59 Hz, so average frequency over times is 60 Hz and mechanical clocks stay on time.
While frequency was at 59 Hz, 5000US dropped offline due to frequency out of spec.
I also have (SunPower branded) 8000US, which also dropped offline.

I think at 62 Hz, I've seen 8000US drop offline for frequency, but 5000US did not. That could be an issue with SunPower specific firmware. So will focus on the issue the SMA branded 5000US exhibits. (Could also be slight tolerance of frequency limits.)

Previously I used 10000TL-US which in backup mode tolerated wide frequency variations but did not reduce output power. In Offgrid mode it worked fine.

I have a suspicion parameters used in backup mode, or "boolean" logic selection of which modes select which parameters, has bugs in 5000US as it did for 10000TL-US.

I know a few of you guys use Sunny Island with Sunny Boy. Any of you use backup configuration and RS-485? Have you observed how it behaves in this regard, or could you run an experiment? I put in an inquiry to SMA support two weeks ago, received automated acknowledgement but nothing else.

 

[Bluedog225]

This sounds awful. Sorry you are having to dive so deep.

While I respect that it is a good brand, this type of German customer service is similar to what I’ve seen in other areas.

Translated, it means that someone lower tech like me would be SOL.

 

[Hedges]

Thanks.
Installers, if aware of the issue, might do the obvious workaround (offgrid mode). But I concern myself with why backup was implemented differently.

They did address the 10000TL-US issue which was my original post.
After I told them I suspected the firmware failed to say, "If (backup OR offgrid) then enableFrequencyBasedPowerReduction", only said "if offgrid then enableFrequencyBasedPowerReduction", they had engineers in Germany look into code and confirmed it didn't work. So they gave the me workaround of setting Sunny Boy to offgrid when behind Sunny Island.

The functionality was implemented and documented long ago, and a dozen inverters of several model families are supposed to support it:

https://files.sma.de/downloads/SB-OffGrid-TI-US-en-22.pdf

It would seem they didn't confirm all functions & operating modes for each. These days probably 98% of Sunny Boy sales are on-grid and 1.5% are off-grid. If 0.5% are grid-backup and it basically functions, maybe nobody ever notices if it doesn't function quite right. But if you're near the equipment doing work and you hear the relay clack, you looks at the display to see why.

Latest -40 and -41 models don't have a grid-backup mode, but they have UL-1741-SA frequency-watts, which is close enough for most customers. The difference is not as wide a frequency or voltage tolerance, might not be great for users with generator as well as grid (even smaller percentage of sales.) In a video SMA said to set those to off-grid when behind Sunny Island. That contradicts their written documentation. I'd rather see such instructions in writing from the engineers who had a reason to implement a separate grid-backup function in the first place.

 

[daklein]

Turn off 250.11 AfraEna in the Sunny Island inverters? That's what I have done with older grid-tie enphase inverters AC coupled, otherwise they trip off when below nominal 60Hz. Sure, some clocks in the house creep forward, but I'd rather have the AC coupled solar not dump off due to the lower frequency when the solar could be used.

I think I have noticed, even with AfraEna disabled, sometimes the SI will go to a lower frequency still. I'm not sure why.

I guess that's not the topic of the thread though: are there SMA solar inverters that will ignore the lower frequency in off-grid mode, so that SI AFRA mode can keep the off grid clocks more accurate.

 

[Hedges]

Yes, off-grid mode of Sunny Boy 10000TL-US works over the frequency range my SI delivers.

Older document SB-OffGrid-TI-eng-UUS121312.pdf says

"Backup systems with SI 4548-US-10, SI 5048U and SI 6048-US-10
In the event of a power distribution grid failure, the off-grid inverter sets the "Default" parameter of the PV
inverter to "OFF_Grid". Thus, if a grid failure occurs, the off-grid inverter is able to regulate the PV inverters via
Frequency Shift Power Control (FSPC). When the grid returns, the off-grid inverter sets the "Default" parameter
of the PV inverter back to "UL1741"."

"The setting of the "Default" parameter to "OFF_Grid" automatically sets the PV inverter parameters to the values
listed in the following table:"

"Fac-delta‒ lower range in which the Sunny Boy is active relative to f0 Hz ‒3.0 (starting from the base frequency f0)
Fac-max+ upper range in which the Sunny Boy is active relative to f0 Hz +3.0 (starting from the base frequency f0)"

I suspect "Default" parameter isn't literally changed, and the -3.0 Hz setting doesn't happen.
Sunny Boy 5000US does note that it is in backup mode and mostly works, but I suspect not everything gets set right.

I might have to Turn off 250.11 AfraEna, but I was planning things like dumb mechanical timers to shut off loads at peak rate times.
I have used Harbor Freight timers but the relays fail. I got some others which I'll switch power contactors with.

"Creep forward", you say. You don't have the excess power I do. Off-grid, it spends a lot of time at 62 Hz. That's 3.3% fast several hours per day, would slip my timers by an hour in no time, and mess up my time of use dodge.

 

[daklein]

"Creep forward", you say. You don't have the excess power I do. Off-grid, it spends a lot of time at 62 Hz. That's 3.3% fast several hours per day, would slip my timers by an hour in no time, and mess up my time of use dodge.

We got a new induction kitchen stove recently, and my wife observed the clock getting faster, not sure exactly how much. RPi node red controls turn on extra loads and transfer one array with about half the solar back to the grid, in response to the battery voltage and the SI frequency. The remaining solar microinverters trip off at only 60.5 Hz. So generally it doesn't spend a lot of time above 60, and when it does, it tops out at 60.5