Sunny Boy Grid Tied Inverter in Island Mode 60hz

[Hedges]

I think there is an Ethernet/Speedwire card for Sunny Island, but last I heard it didn't support the on/off grid communication needed by Sunny Boy.
I figured that might get implemented in firmware of SI 8.0, and it is possible that is supported by SI 6048US. You could email SMA support to ask.

If you put RS-485 card in master Sunny Island and one in each Sunny Boy, and set Sunny Boy to grid-backup:

Backup mode = On all
or
Op.BckOpMod = OnAllPhs

Then it will enable backup automatically when SI disconnects from grid.

Are you switching AC wires of Sunny Boy from grid to island side of Sunny Island? I thought about that, and would have switched RS-485 as well. Don't want Sunny Island setting "backup" mode while Sunny Boy is connected direct to grid. But, I have never seen the Sunny Island message with an oscilloscope. I don't know if it is a one-time message, or a repeating "keep alive" message. So I don't now if switching RS-485 will let the message through vs. blocking "backup" mode, or if doing so might miss the message and leave Sunny Boy in wrong state.

When I discovered 10000TLUS did not respond to frequency shift by reducing power output (simply remained connected at full power up to 64.5 Hz), SMA America acknowledged the bug and gave me the work-around of using off-grid ("Island") mode for that model Sunny Boy when behind Sunny Island (NOT directly on grid) whether running with grid connected or during power failures.

That worked, but I have a concern. It disagrees with written instructions from SMA Germany:

"For PV inverters without backup mode, 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."

Although it works just fine, I think there was a reason the developers implemented a backup mode rather than just on-grid for direct grid connection and off-grid when behind Sunny Island, regardless of whether a grid is connected or not. Going through FMEA, one would realize the relay could get welded and leave grid and island side connected. Sunny Island (if so designed) could recognize relay never opened, and not invert to produce AC from battery. It could decide not to tell Sunny Boy to enter backup mode. With Sunny Boy still in UL-1741 mode, anti-islanding would guarantee it shut off.

If Sunny Boy was set to off-grid, relying on Sunny Island to isolate it during grid-down, that wouldn't happen in case of welded relay. Grid would remain connected to Sunny Boy, which would not perform anti-islanding and could continue to deliver power. So I didn't trust the workaround I was given, and have since switched to SB 5000US which works as intended with RS-485.

 

[MurphyGuy]

I think there is an Ethernet/Speedwire card for Sunny Island, but last I heard it didn't support the on/off grid communication needed by Sunny Boy.
I figured that might get implemented in firmware of SI 8.0, and it is possible that is supported by SI 6048US. You could email SMA support to ask.

If you put RS-485 card in master Sunny Island and one in each Sunny Boy, and set Sunny Boy to grid-backup:

Backup mode = On all
or
Op.BckOpMod = OnAllPhs

Then it will enable backup automatically when SI disconnects from grid.

Are you switching AC wires of Sunny Boy from grid to island side of Sunny Island? I thought about that, and would have switched RS-485 as well. Don't want Sunny Island setting "backup" mode while Sunny Boy is connected direct to grid. But, I have never seen the Sunny Island message with an oscilloscope. I don't know if it is a one-time message, or a repeating "keep alive" message. So I don't now if switching RS-485 will let the message through vs. blocking "backup" mode, or if doing so might miss the message and leave Sunny Boy in wrong state.

My Sunny Islands connect to my home in the exact same way as one would do with a portable generator hooked up legally using a patch cord. I have a "generator interlock" breaker that is back fed.. To turn it on, the main breaker to the utility meter must be off.

My off-grid system is a box on wheels that remains completely isolated on all 4 lines at all times when not in use. I use a 4 wire 4ga SO cord to connect.

Once connected, the SI's power the house and the solar system thinks the grid is back up.. Once its running, I boogie over to the computer, log into the Sunny Boy's and set them for Island Mode. I don't have to set them for Island Mode.. its not required for the system to successfully operate and power the house.. but it makes things smoother once the batteries are full.

I'm pretty sure (not 100%) that even in Island Mode, the Sunny Boy inverters will NOT make power if they don't detect a grid.. I think the only thing the Island Mode does is open up some of the grid specs to allow for a slightly sloppier signal.

In other words, if if left in Island Mode while connected to the grid, I'm pretty sure the Sunny Boy's would shut down if the grid went down.. But again, I haven't tested it.

When I discovered 10000TLUS did not respond to frequency shift by reducing power output (simply remained connected at full power up to 64.5 Hz), SMA America acknowledged the bug and gave me the work-around of using off-grid ("Island") mode for that model Sunny Boy when behind Sunny Island (NOT directly on grid) whether running with grid connected or during power failures.

That worked, but I have a concern. It disagrees with written instructions from SMA Germany:

"For PV inverters without backup mode, 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."

Although it works just fine, I think there was a reason the developers implemented a backup mode rather than just on-grid for direct grid connection and off-grid when behind Sunny Island, regardless of whether a grid is connected or not. Going through FMEA, one would realize the relay could get welded and leave grid and island side connected. Sunny Island (if so designed) could recognize relay never opened, and not invert to produce AC from battery. It could decide not to tell Sunny Boy to enter backup mode. With Sunny Boy still in UL-1741 mode, anti-islanding would guarantee it shut off.

If Sunny Boy was set to off-grid, relying on Sunny Island to isolate it during grid-down, that wouldn't happen in case of welded relay. Grid would remain connected to Sunny Boy, which would not perform anti-islanding and could continue to deliver power. So I didn't trust the workaround I was given, and have since switched to SB 5000US which works as intended with RS-485.

OH.. I see the problem.. good explanation.

My issue is that I don't trust the grid not to smoke my Sunny Islands.. A direct lightening hit and I'm out $10k worth of inverters. I keep my off-grid system completely isolated at all times.. When the grid goes down, it takes me about 3 minutes to boot things back up.. And since I keep my lithium bats at only 3.6 volts in storage, I don't have to worry about re-configuring the Sunny Boy's into Island Mode for several hours.

Last year, the town I live outside of had a huge power surge that smoked well over 100 appliances in town.. Town's facebook page was filled with complaints about furnaces, dishwashers, televisions, etc.. all toast.

We keep our computers on a UPS and that's good enough for me.. 3 minutes without juice doesn't cause a problem.

 

[robby]

My Sunny Islands connect to my home in the exact same way as one would do with a portable generator hooked up legally using a patch cord. I have a "generator interlock" breaker that is back fed.. To turn it on, the main breaker to the utility meter must be off.

That was the first solution that SMA offered me. My problem is that I have a reef Aquarium and if that goes down when I am not home it's going to be catastrophe.

My off-grid system is a box on wheels that remains completely isolated on all 4 lines at all times when not in use. I use a 4 wire 4ga SO cord to connect.

Once connected, the SI's power the house and the solar system thinks the grid is back up.. Once its running, I boogie over to the computer, log into the Sunny Boy's and set them for Island Mode. I don't have to set them for Island Mode.. its not required for the system to successfully operate and power the house.. but it makes things smoother once the batteries are full.

I'm pretty sure (not 100%) that even in Island Mode, the Sunny Boy inverters will NOT make power if they don't detect a grid.. I think the only thing the Island Mode does is open up some of the grid specs to allow for a slightly sloppier signal.

I was told it can do it but I have never seen it demonstrated by anyone. When I asked SMA they pretty much sent me in circles with the various answers. Verbally I always get positive answers but when I ask the same question in an email I get a different answer. They don't want to put it in writing and that was what pushed me away from SMA.

In other words, if if left in Island Mode while connected to the grid, I'm pretty sure the Sunny Boy's would shut down if the grid went down.. But again, I haven't tested it.

Please try it one day.

OH.. I see the problem.. good explanation.

My issue is that I don't trust the grid not to smoke my Sunny Islands.. A direct lightening hit and I'm out $10k worth of inverters. I keep my off-grid system completely isolated at all times.. When the grid goes down, it takes me about 3 minutes to boot things back up.. And since I keep my lithium bats at only 3.6 volts in storage, I don't have to worry about re-configuring the Sunny Boy's into Island Mode for several hours.

You can buy Lightning protectors for the panel box from various companies. I use one of the "EATON" models, I put it in after the Installation of the Inverter. My electrician has said that he has seen businesses get strikes and the EATON saved the appliances inside at the expense of its own life.

Last year, the town I live outside of had a huge power surge that smoked well over 100 appliances in town.. Town's facebook page was filled with complaints about furnaces, dishwashers, televisions, etc.. all toast.

We keep our computers on a UPS and that's good enough for me.. 3 minutes without juice doesn't cause a problem.

I have had the same experience about 12 or more years ago. My APC UPS systems saved all my electronic equipment and my Fridges are always plugged into a Fridge Guard. My neighbors were not so lucky.
I think I only lost a couple of minor things.

 

[MurphyGuy]

That was the first solution that SMA offered me. My problem is that I have a reef Aquarium and if that goes down when I am not home it's going to be catastrophe.

There's a big difference between powering an aquarium and powering an entire home. Perhaps a smaller less expensive sub-system for it? How much juice does an aquarium suck up? That must be one hell of a fish tank.
My only experience is with a 50 gallon unit, and that could have been powered by a single solar panel with an AGM battery.

My desire to protect those $10,000 inverters is strong.. LOL

I was told it can do it but I have never seen it demonstrated by anyone. When I asked SMA they pretty much sent me in circles with the various answers. Verbally I always get positive answers but when I ask the same question in an email I get a different answer. They don't want to put it in writing and that was what pushed me away from SMA.

Please try it one day.

The SMA inverter operating in Island Mode is still a reactive system with limits.. If the frequency or voltage goes out of spec, they shut down.. so I would think that when the grid evaporated, so would the SunnyBoy's output.

Maybe I'll test it one day.. I do know that when our grid power comes back and I shut down the off-grid system, the Sunny Boy's, still in Island Mode, drop out.. But I've never sat there an inspected things.. and usually, after flipping the main breaker on, the Sunny Boy's are back in production and pumping energy back to the grid by the time I make it back to the computer.

You can buy Lightning protectors for the panel box from various companies. I use one of the "EATON" models, I put it in after the Installation of the Inverter. My electrician has said that he has seen businesses get strikes and the EATON saved the appliances inside at the expense of its own life.

I have had the same experience about 12 or more years ago. My APC UPS systems saved all my electronic equipment and my Fridges are always plugged into a Fridge Guard. My neighbors were not so lucky.
I think I only lost a couple of minor things.

I have one too.. within a month after the appliance terminator showed its ugly head, I installed a Siemens FS140.. Then my neighbor had me install one in his house as well..

 

[Hedges]

In other words, if if left in Island Mode while connected to the grid, I'm pretty sure the Sunny Boy's would shut down if the grid went down.. But again, I haven't tested it.


OH.. I see the problem.. good explanation.

Off-grid they will tolerate much wider voltage and frequency. With frequency-watts, they might even match themselves to a motor load and keep it going?

Not counting frequency-watts, "Anti-Islanding" was described as being needed for a degenerate case of resonant load perfectly matched to PV production. A situation never observed in the wild, but demonstrated in the lab. Active anti-islanding tests grid impedance to make sure it is a bottomless ocean of power, not a closely matched load.

Sunny Boy in island mode would likely shut down with grid down. But a million systems out there, with line broken connecting just household loads and maybe a neighbor's house, possibly one of them would stay up indefinitely. If it can be done in the lab it might electrocute a lineman some day.

I would also worry about zero-export systems. Zero probably within +/-100 mA? Without active anti-islanding, I would worry those might power grid connection with wires broken. I would prefer only UL-1741 listed with anti-islanding control of power output.

 

[robby]

This was what SMA sent me on how to do it using Single Phase 240V equipment,
Flexible Storage
I am not sure why the US Split phase systems cannot do the same thing but they started to sell me on this idea and then added that I would need to use two Autotransformers. The whole thing got ridiculously expensive, the final straw was that I could not get a written guarantee it would work. Oh there where plenty of verbal guarantees.

 

[Hedges]

Were you trying to use Sunny Island for peak shaving in U.S., and only European model did that function?

It looks like SI 8.0 does that with home manager. External transfer switch required for backup operation even though SI appears to have two AC connections?

https://www.estg.eu/nl-nl/amfile/file/download/file/2082/product/2514/

Using a 230V line/neutral inverter you would of course need transformers. Two only if both AC ports of the inverter used.

For US market, Sunny Boy Storage has the peak shaving function. That one requires ABU to provide transfer switch and transformer.

It ought to be doable with just Sunny Island 6048US (x2 or transformer), having Sunny Boy and loads downstream. Nothing else but firmware, however that is the hardest part.

 

[SolarPrep]

Hedges/Robby/MurphyGuy:

Hours of reading later, I am thoroughly confused. Wow. Thank you all for the links.

So, inquiring minds want to know if a Sunny Boy, set permanently to off grid mode, could be used to harvest PV energy, and that energy could be used for direct consumption, or stored in batteries. With the assumption that you don't want to export to grid, ever, and you have a diversion load capable of taking any excess energy.

Much of what I read deals with the Sunny Island, and its role when hooked to Sunny Boy. Is that absolutely required in all cases?

Thanks for your time. Very much appreciated.

 

[Hedges]

Sunny Boy, like any other grid-tie inverter, will shut off if grid goes down. That is for lineman safety and is part of UL-1741.

You can get batteries-optional hybrid inverters from various sources.

Newer Sunny Boy (-40 and -41 models) have "Secure Power" feature, which can be enable with a switch when grid is down. It will produce up to 2000W 120VAC direct from PV, with no batteries. You could use that to power a battery charger. But that system has no communication, doesn't know when PV production droops. It would function as long as loads including battery charger are less than production. Note I haven't described what you would do with the charged battery; that could be DC loads or feed an inverter for other AC loads.

Sunny Island or another AC coupled battery inverter is a much better way to use GT PV inverters off-grid. These will create an island grid for your house without needing utility connection. They power your house from battery, allow Sunny Boy to also deliver power, charge battery from surplus Sunny Boy production, and request reduced production if not needed for loads or battery (by raising frequency above 60 Hz to as high as 62 Hz.)

Sunny Island is 120V, so you need either two of them or a 120/240V transformer. Some brands of AC coupled battery inverter are 120/240V already. Some (Sunny Boy Storage) are 240V only so again would need transformer.

More common for off-grid is DC coupled, SCC harvests PV power to charge battery. If battery gets low, inverter shuts down but SCC keeps working.
You can do off-grid with AC coupled. If no DC coupled included, need a relay to disconnect AC loads when battery low so Sunny Boy remains connected with AC, can deliver power to recharge battery.

AC coupled is bit complicated and expensive, but works well. Seems to be good for larger systems in the 6kW to 48kW range. I think it is particularly good for a system with oversize PV array and undersize battery, where most power is used direct PV to AC (e.g. running my A/C during the day.)

 

[melkier]

Hedges/Robby/MurphyGuy:

Hours of reading later, I am thoroughly confused. Wow. Thank you all for the links.

So, inquiring minds want to know if a Sunny Boy, set permanently to off grid mode, could be used to harvest PV energy, and that energy could be used for direct consumption, or stored in batteries. With the assumption that you don't want to export to grid, ever, and you have a diversion load capable of taking any excess energy.

Much of what I read deals with the Sunny Island, and its role when hooked to Sunny Boy. Is that absolutely required in all cases?

Thanks for your time. Very much appreciated.

I have 60x305W panels and 3x6kw sunny boys set up in island mode. I have 4xsunny island 6048s with lithium batteries. The sunny boys are connected to the output (AC1) side of the sunny islands, which is connected to my house main load center. The PV energy from the sunny boys is used directly by the house when the sun is out, any remaining is put into charging the batteries. Once the batteries are charged and we're not using all the power the PV panels are putting out, the sunny island will increase the frequency (read up on frequency shift power control), which will in turn signal the sunny boys to reduce power output so no diversion load is necessary. I have other loads here (like a rheem hybrid water heater that will kick into high demand/electric mode) that watch when frequency goes above/below a certain amount. All in all, it's a good system and I'm pretty happy with it.

I know a few folks with JUST sunny islands (and no sunny boys) and some with JUST sunny boys that are working in grid tied mode, so they are not required to work with each other. The guys with the sunny islands and no sunny boys use lead acid with midnight or victron charge controllers just as you would with any other inverter. The SI kits come with battery temp and current sensors for this type of setup.

You can even use the sunny island as just an AC-connected battery backup unit (basically disabling params GdPwrEna and GdSocEna and setting GdManStr Auto), which will keep grid connected - passthrough - all the time and then provide battery power when grid is out). You can even feed the grid from the batteries - I've seen some folks say it's not possible but the manual even talks about it and I did it once to just test.

 

[robby]

I have 60x305W panels and 3x6kw sunny boys set up in island mode. I have 4xsunny island 6048s with lithium batteries. The sunny boys are connected to the output (AC1) side of the sunny islands, which is connected to my house main load center. The PV energy from the sunny boys is used directly by the house when the sun is out, any remaining is put into charging the batteries. Once the batteries are charged and we're not using all the power the PV panels are putting out, the sunny island will increase the frequency (read up on frequency shift power control), which will in turn signal the sunny boys to reduce power output so no diversion load is necessary. I have other loads here (like a rheem hybrid water heater that will kick into high demand/electric mode) that watch when frequency goes above/below a certain amount. All in all, it's a good system and I'm pretty happy with it.

I know a few folks with JUST sunny islands (and no sunny boys) and some with JUST sunny boys that are working in grid tied mode, so they are not required to work with each other. The guys with the sunny islands and no sunny boys use lead acid with midnight or victron charge controllers just as you would with any other inverter. The SI kits come with battery temp and current sensors for this type of setup.

You can even use the sunny island as just an AC-connected battery backup unit (basically disabling params GdPwrEna and GdSocEna and setting GdManStr Auto), which will keep grid connected - passthrough - all the time and then provide battery power when grid is out). You can even feed the grid from the batteries - I've seen some folks say it's not possible but the manual even talks about it and I did it once to just test.

In this day of LIfePO4 batteries Is there anyway to make the Sunny Islands power the whole house from lets say 100% SOC down to 20% SOC every night and then go back on Grid?
This would cut down on peoples electric bill significantly. I figure you could do it with a Transfer switch and kill the Grid manually but then you would have to monitor it to know when to switch back to the Grid.

 

[Hedges]

I think so, "Grid Charge"
It would depend on what options for when to connect.

For "Generator", it has features to enable generator at some SoC, and during night time hours allow lower SoC before starting generator to avoid noise.

If nothing else, you could tell SI it has a generator, but really connect grid through a relay to SI. Use the "generator start" dry contacts to close relay and connect grid.

What we will want is better features for shifting consumption between various hours by charging/discharging battery. Sunny Boy Storage is made for that. SI 8.0 I think does that. Software for SI-6048 to do it? Software is much more difficult than hardware, takes longer, is more expensive. My guess is such firmware won't be offered, just the 8.0 model when it comes here.

 

[robby]

I think so, "Grid Charge"
It would depend on what options for when to connect.

For "Generator", it has features to enable generator at some SoC, and during night time hours allow lower SoC before starting generator to avoid noise.

If nothing else, you could tell SI it has a generator, but really connect grid through a relay to SI. Use the "generator start" dry contacts to close relay and connect grid.

Sounds like a brilliant idea! The only possible problem is if the SI is programmed to do something if it does not see Gen power appearing on the connections. Knowing SMA I suspect they will kill the Gen start contacts if the unit does not see power in xx amount of seconds.

What we will want is better features for shifting consumption between various hours by charging/discharging battery. Sunny Boy Storage is made for that. SI 8.0 I think does that. Software for SI-6048 to do it? Software is much more difficult than hardware, takes longer, is more expensive. My guess is such firmware won't be offered, just the 8.0 model when it comes here.

Yes that is what I do with my Inverter. It comes on at 11pm with batteries and runs the house until 5am. I need one more battery pack to get me to 7am, at that point the PV is producing enough to power the house and by 8am it is charging back the batteries. If your wondering why 11pm it is because about 70% of the power outages we have occur at around 8-9pm.
If that happens I want the batteries fully charged so that I can flip on my Honda Eu3000 on and have it take over the 120V loads. I can then run all the 240V appliances like normal including the ACs and get through the night and into the next morning if need be. It's rare that the outages last longer than 2 hours but every year there is at least one that goes all night into the next day.

 

[melkier]

In this day of LIfePO4 batteries Is there anyway to make the Sunny Islands power the whole house from lets say 100% SOC down to 20% SOC every night and then go back on Grid?
This would cut down on peoples electric bill significantly. I figure you could do it with a Transfer switch and kill the Grid manually but then you would have to monitor it to know when to switch back to the Grid.

That's how I run mine. Normally, I have both GdPwrEna and GdSocEna enabled. I have it switch to grid automatically if I'm using more than 4kw of load (which means when I'm not producing adequate PV power - this typically never happens during the day) and turn off again when it's below 3k. I also have it switch to grid automatically when the batteries reach 35% and stay there until they get recharged from PV (the sunny island will turn off the grid if there's enough power from PV). Lately, we've been running from the grid quite a bit - it's been overcast/raining. Typically, during the day, the grid will shut off when we generate PV and then we use the batteries at night until they're empty then it switches to grid again.

Keep in mind, I wrote my own BMS for my lithium batteries and I also control the sunny island with it. I have it switch to different modes when the grid is connected vs generator vs nothinng.

I also have my whole-house generator controlled from the sunny island (in my case, it required 2 relays, one to signal when grid was out, the other to start the generator as mine doesnt have a "remote start feature" but only starts when power is interrupted so I use a relay which is normally connected and then disconnects it when sunny island wants it to start). The generator will automatically start if the grid is down and the battery goes down to 25% and will keep running until the battery is 90% then automatically shut off.

So far it works pretty well but I'm always "tweaking" the system lol. I wrote the original code in C but I'm adding javascript capabilities to it so I change some of the logic without restarting the service every time (because if it crashes and the sunny island doesnt hear from the "BMS" via the CAN bus in a certain amount of time, it will error out and go into standby and you wont have power).



Here's an example of what I was talking about ... We were using a lot of power @ night on the 12th (was cold has several heaters going) then the battery runs out and we started using the grid ... until 8:30-ish am and the sun came out ... the grid turns off and batteries get charged and then we run on batts until the 13th at around 5am.

The spike you see is the sunny island trying to switch the grid back on before the batteries are at 45% and trying to charge the batteries at ~150 amps until my bms detects the grid is connected and sets the charge amps to grid_charge_amps (2). I re-wrote that part to do it within 1 second versus waiting until the next read/write cycle - 10 seconds.

 

[robby]

That's how I run mine. Normally, I have both GdPwrEna and GdSocEna enabled. I have it switch to grid automatically if I'm using more than 4kw of load (which means when I'm not producing adequate PV power - this typically never happens during the day) and turn off again when it's below 3k. I also have it switch to grid automatically when the batteries reach 35% and stay there until they get recharged from PV (the sunny island will turn off the grid if there's enough power from PV). Lately, we've been running from the grid quite a bit - it's been overcast/raining. Typically, during the day, the grid will shut off when we generate PV and then we use the batteries at night until they're empty then it switches to grid again.

Keep in mind, I wrote my own BMS for my lithium batteries and I also control the sunny island with it. I have it switch to different modes when the grid is connected vs generator vs nothinng.

I also have my whole-house generator controlled from the sunny island (in my case, it required 2 relays, one to signal when grid was out, the other to start the generator as mine doesnt have a "remote start feature" but only starts when power is interrupted so I use a relay which is normally connected and then disconnects it when sunny island wants it to start). The generator will automatically start if the grid is down and the battery goes down to 25% and will keep running until the battery is 90% then automatically shut off.

So far it works pretty well but I'm always "tweaking" the system lol. I wrote the original code in C but I'm adding javascript capabilities to it so I change some of the logic without restarting the service every time (because if it crashes and the sunny island doesnt hear from the "BMS" via the CAN bus in a certain amount of time, it will error out and go into standby and you wont have power).

View attachment 76323

Here's an example of what I was talking about ... We were using a lot of power @ night on the 12th (was cold has several heaters going) then the battery runs out and we started using the grid ... until 8:30-ish am and the sun came out ... the grid turns off and batteries get charged and then we run on batts until the 13th at around 5am.

The spike you see is the sunny island trying to switch the grid back on before the batteries are at 45% and trying to charge the batteries at ~150 amps until my bms detects the grid is connected and sets the charge amps to grid_charge_amps (2). I re-wrote that part to do it within 1 second versus waiting until the next read/write cycle - 10 seconds.

We seem to be in sync on how our systems are setup to run
That is some very impressive software that you made. I suspect that SMA like most of the big Inverter companies does not share any kind of API's or documentation on how to Interface with their hardware, so I suspect you had to do this the hard way?

Here is some data from mine.

This first shot is everything in one on a day when the puffy clouds kept passing by, I highlighted the readings when the PV output dropped enough that the batteries kicked in to prevent it from using grid power.



In this shot I turned off all the other graph data except the Grid power being consumed. As you can see at 11pm the batteries take over and they run until about 5am.



I need another 15KWh of batteries to really utilize my panels. I have another 5Kw battery coming soon and that should make it go from 11pm to 7am on battery power.

 

[melkier]

I have 50kw of batteries (of which I only use 30k) and we STILL run out. We're in an old victorian with multiple buildings on the property and we use a ton of power (still have knob & tube wiring - the top of the posts are marked 1925 - the wire itself uses like 900 watts).

Actually I have some ~ok docs from SMA. I also wrote my own SMANET library (which talks to the sunny island over RS485) since the YASDI one they have is so horrible:

solardirector/smanet at main · sshoecraft/solardirector

Contribute to sshoecraft/solardirector development by creating an account on GitHub.

github.com

The current sources for the SI agent/bms is here:

solardirector/agents/si at main · sshoecraft/solardirector

Contribute to sshoecraft/solardirector development by creating an account on GitHub.

github.com

It's a work in progress and the current sources on github are not actually what I'm running in prod atm. If you're interested in how to read/write to the sunny island over can bus, see read.c and write.c in that directory.

 

[robby]

I have 50kw of batteries (of which I only use 30k) and we STILL run out. We're in an old victorian with multiple buildings on the property and we use a ton of power (still have knob & tube wiring - the top of the posts are marked 1925 - the wire itself uses like 900 watts).

Actually I have some ~ok docs from SMA. I also wrote my own SMANET library (which talks to the sunny island over RS485) since the YASDI one they have is so horrible:

solardirector/smanet at main · sshoecraft/solardirector

Contribute to sshoecraft/solardirector development by creating an account on GitHub.

github.com

The current sources for the SI agent/bms is here:

solardirector/agents/si at main · sshoecraft/solardirector

Contribute to sshoecraft/solardirector development by creating an account on GitHub.

github.com

It's a work in progress and the current sources on github are not actually what I'm running in prod atm. If you're interested in how to read/write to the sunny island over can bus, see read.c and write.c in that directory.

Nice! I am sure some SI owners are going to be looking at using your software.
I have 16KWh of LIfePO4 batteries, if I had 30KWh I would be off the Grid.

You should start a DIY project and get the house rewired bit by bit and looking for cheap upgrades you can do to shave some of that power usage. I wish I could find ways to cut some more of my electricity usage but even before I got Solar I had spent the last three years making everything as efficient as possible because the electric bill was so high. The only thing I have left is changing the Hot water heater and putting in one twice the size. I was shocked at how expensive the newer heaters are and then they also have the long back order delays on most models.

As it is now we still have to turn it on again at night to heat enough water for the last person to shower. I was thinking of wiring a new heater to the dump load connection on the Inverter but after a two week experience of seriously overcast and rainy days I realized I cannot fully depend on solar. It's really a learning curve on finding ways to improve the system and hopefully getting fully off the Grid and just having it as a backup.

 

[SolarPrep]

In this day of LIfePO4 batteries Is there anyway to make the Sunny Islands power the whole house from lets say 100% SOC down to 20% SOC every night and then go back on Grid?
This would cut down on peoples electric bill significantly. I figure you could do it with a Transfer switch and kill the Grid manually but then you would have to monitor it to know when to switch back to the Grid.

This is exactly what I want.

 

[SolarPrep]

Melkier: very nice work you have done. I share your pain with the Victorians. I've done a lot of them, the last one being over 12,000sf. That old knob and tube wiring was tough stuff, and often is in pretty good shape. The worst part about it is how they would branch off all over the place, often with no particular plan. The first thing I do is set up a new Square D QO panel, and start in.

 

[melkier]

Nice! I am sure some SI owners are going to be looking at using your software.
I have 16KWh of LIfePO4 batteries, if I had 30KWh I would be off the Grid.

You should start a DIY project and get the house rewired bit by bit and looking for cheap upgrades you can do to shave some of that power usage. I wish I could find ways to cut some more of my electricity usage but even before I got Solar I had spent the last three years making everything as efficient as possible because the electric bill was so high. The only thing I have left is changing the Hot water heater and putting in one twice the size. I was shocked at how expensive the newer heaters are and then they also have the long back order delays on most models.

As it is now we still have to turn it on again at night to heat enough water for the last person to shower. I was thinking of wiring a new heater to the dump load connection on the Inverter but after a two week experience of seriously overcast and rainy days I realized I cannot fully depend on solar. It's really a learning curve on finding ways to improve the system and hopefully getting fully off the Grid and just having it as a backup.

Yep I had planned to do the same (making everything as efficient as possible then going to solar) however, covid changed a lot of my plans - not covid per se, but the economic impact and supply chain problems from it. Wife and I decided it might be best go with solar now vs later and build out infra for self-sustainable living (large chicken coop/greenhouse with aquaponics, etc). The price of lettuce today tells me I'm on the right track and its only getting worse.

We got a rheem hybrid when the water heater died earlier this year. It cost way more than I would have every thought I'd pay for a damn water heater lol. It's a good unit and we're pretty happy with it. I have the pyeconet module and control it via automation. It definitely fits in with our efficiency goal and solar (uses like 460 watts in heat pump mode).

I knew I could not depend on solar 24x7x365 unless I had way more battery than was reasonable. It's why I got the generator too - for those times when the batteries are low and the grid is out. Honestly, I really should have about 2400AH of battery and currently only have 1100AH. The current "plan" is to feed surplus solar to the grid and get "credits" for it to use on non-sunny days and high-use nights (grid as a generator AND a battery).

 

[melkier]

Melkier: very nice work you have done. I share your pain with the Victorians. I've done a lot of them, the last one being over 12,000sf. That old knob and tube wiring was tough stuff, and often is in pretty good shape. The worst part about it is how they would branch off all over the place, often with no particular plan. The first thing I do is set up a new Square D QO panel, and start in.

Yep the wiring is in pretty good shape for it's age and I definitely plan on replacing it, but since it's not a problem I have other high prio projects to work on first (squeaky wheel gets the grease).

Love the Victorian. Now that we've lived in a house with 12 foot ceilings I don't know if I could ever go back lol.

 

[Ai4px]

This is a pretty active thread! I'd like to ask a few questions... I presently have two 6048 sunny islands with 45kwh of batteries. My present system is comprised of solaredge 11400 and a SB3.8-1SP-US-41. I got the grid guard code and can put the sunny boy behind the sunny islands, works like a champ. But it only gives me 3.5kw or so.... so I'd like to swap out some of my solar edge panels to anohter sunny boy. is there any reason I shouldn't use the seemingly older model SB5000TL or SB6000TL ? I read the docs and you use dip switches to set it to island mode 60hz, that should be it, right?

 

[Hedges]

If you have multiple orientations of PV panels available you can overpanel the -41 a bit without losing production due to clipping.

The following document says SB 5000TL-US-22 is OK for battery-backup grid-tied system but not for off-grid system (that's a puzzle, whenever grid is down battery-backup is just like off-grid)
Also, SB 5000TLUS-12 OK for off-grid system but not battery-backup system.

The second one (-12) I know about. I'm the reason - I told SMA about the issue. For grid-tied battery backup, SI sends a signal over RS-485 to inform SB of on/off grid state, and that SI is watching its back. Turns out the "backup" setting of TLUS-12 does widen frequency range, but fails to ramp down wattage output with frequency. With "island" or "off-grid" setting, it works as desired. (Even in a backup system, SMA support gave me that work-around. But I have some concerns about it; the developers did not recommend using it that way for backup. I have a guess as to why, related to lineman safety.)

Why would -22 work for backup but not off-grid? My guess is it needs to be wired with whatever communication used in grid-tied battery-backup. Then if used off-grid it could just always think the grid was down.

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

You've got Grid Guard code and can diddle with parameters, but only once SB has booted its firmware and started talking to you. At least some models won't do that until they've connected on AC side, and if shipped configured for grid, they won't connect while SI is sitting at 59Hz as it is wont to do. I got around that by closing switch reconnecting grid to SI input. SMA began shipping inverters pre-configured in "backup" mode rather than "UL-1741" mode, I would guess for that reason.

 

[robby]

The more I learn about SMA is the more confused I get.
It seems like they are either control freaks who are overly cautious about the way they will allow their equipment to be used or they have an all in one Hybrid model in the works and it's going to be very very expensive and they do not want people trying to use their other products to cobble together something after it's release that can do the same thing.
If it is a proper full featured all in one, I suspect it will make the Sol-Arks price look cheap by comparison.

An engineering friend that that deals with the design of Solar Equipment said to me just last week that Sol-Ark better be prepared as they are going to be facing some serious competition in 2022.

 

[Hedges]

SMA has offered GT PV and separate battery island-forming inverters for decades.
They used to have some small 2kW battery models for the European market. Today what I see ranges from 4.5 kW to 4 MW.
I think 220V European model offers a good balance and price-point. One 6kW battery inverter + two 6kW PV inverters as grid-backup.
The US model seems an afterthought, with bypass relay of same current but operating at 120V can only handle 6.7 kW.

I think the weight of < 150 lbs per unit makes the modular approach good. That was transformer type.
Transformerless, each is no more than 75 lbs.

Sunny Boy Storage looks like a bidirectional version of the newer Sunny Boy PV inverter. Since it has 3 DC inputs, I'd like to see those configurable for either battery or PV, then it would be a hybrid. But, it requires an expensive ESS consisting of battery plus bidirectional boot converter.

Both Sunny Boy and Sunny Boy Storage are reasonably priced, like between $1700 and $2700 apiece for 6kW units. But the transfer switch and split-phase transformer also costs as much. Total ~ $7500 for 6kW from PV, 6kW from battery. Somewhat different architecture and PV/AC limits compared to Sol-Ark, probably a bit more expensive per watt but not much.

I think they're aiming at bigger segments of the market. Grid connected storage and PV tied into spot markets, and commercial scale.