SMA Sunny Island Inverter question for Hedges (or anyone who has relevant Sunny Island experience)

MrDan

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Joined
May 17, 2021
Messages
7
Hello Hedges (and everyone), I have been considering the purchase of 4 Sunny Island inverters through eBay. I currently own two Victron inverters and I am pretty comfortable with them and they seem to be working well. The reason I'm considering the purchase of the Sunny Island inverters is because I need more power than the two 3kva inverters I currently have. I could go with a much bigger Victron, but eventually this inverter setup will be in shop building, which is currently off grid but might in the future have a grid connection (I'd like the option either way). Victron does not currently have much to offer in the US from a code compliance perspective. My current inverters probably do not have all of the associated US certifications, and so therefore they are setup in a mobile fashion, similar to using a generator to power a building. I'd like to permanently install the future inverters and pass code compliance certifications (I didn't find anything that seems to indicated that the Sunny Island couldn't pass code compliance in the USA).

I've read posts about AC coupling with Sunny Island and having some issues with inverter models from SMA, but it appears you were able to work through these problems.

Hedges (or anyone with experience) based on experience, would you do it all again and repurchase your Sunny Island inverters, or would you look elsewhere?

I'm really spoiled by the Victron central control, the Cerbo GX device, etc. The Sunny Island website isn't as user friendly as the Victron site in my opinion, and I'm having some difficulty figuring out if I can bridge an older inverter model like the Sunny Island into the SMA tech stack that connects to the internet. Do you know if it is possible to make the Sunny Island connect to the SMA Data Manager M by using an SMA Communication Gateway? https://www.sma.de/en/products/monitoring-control/sma-com-gateway.html

Thanks for your time.

Dan
 

etatdiysolar

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Jun 29, 2021
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I have 4 SIs and 4, 7kw sunny boys, they seem to work together great with frequency shifting. But still new system learning curve. I'm adding a data manager very soon, it should give nice GUI to the SIs. I use a victron GX device (homebrew Pi3) planning to monitor the SIs with special CAN bus code madsci1016 wrote minus the lithium interface. I'm using Lithium but running as lead acid.
 

daklein

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May 8, 2020
Messages
58
I use a victron GX device (homebrew Pi3) planning to monitor the SIs with special CAN bus code madsci1016 wrote minus the lithium interface. I'm using Lithium but running as lead acid.
The SI puts out a different set of CAN messages for lithium mode vs. lead acid. The lead acid CAN messages don't have all the various signals you'll want, which are available in lithium mode. I have FLA batteries with the SI, so I'm using the SI in lead acid mode. I found some relatively obvious signals in the lead acid mode CAN messages, like AC voltage, Hz, target voltage. But others that I'd really like, say battery voltage, current, I haven't figured out those out.

If you're running lithium batteries, why not use lithium mode on the SI? Just need to get a smart shunt like madsci.
 

etatdiysolar

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Jun 29, 2021
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When you set mode to lithium the SI no longer charges the battery! madsci1016 uses a PV DC charger. I have the smartshunt only for monitoring the system, you don't need one if the SI does the charging. Hopefully in VRLA mode it still puts out power in/out on the can bus..
 

toms

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Jul 24, 2020
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749
The Sunny Island will charge your battery in lithium mode if you are using a compatible BMS. (i use the REC BMS with mine)
 

daklein

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May 8, 2020
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58
If they won't work with AC coupled solar in lithium mode, that will kill my future plans. Are you sure? It would need to have a target charging voltage / current / SOC message given to it, along with the battery SOC estimate and some status flags? The REC bms manual lists what the SMA SI expects to receive to work in lithium mode. Page 10: http://www.rec-bms.com/datasheet/UserManual9R_SMA.pdf MurphyGuy is another one using REC bms with SI in lithium mode.

Anyway, I don't know about that for sure, other than I'm positive that the CAN messages available in leadacid mode are not same as in lithium mode. Once you have a CAN interface hooked up with the RPi, see what you can find.

I used the python-can github project to look at the can messages. It has a viewer script that can be given a scaling and labeling file. Here are the signals that I was able to label. The ones that are not labeled look to me like they could be a signal variable, but may or may not be correctly grouped or be the right variable type. Sometime they'll look like they may be a signal of interest, but they don't always make sense, especially when they'll jump to a different offset level. I modified the viewer script to put out mqtt messages for any signals defined by the labeling file. I don't send any messages on the CAN bus, I don't know what there is to send that the SI would expect to see.

I suspect the 060 message was put in so the Midnite / SMA communication box would be able to set Midnite classic target voltages.

Code:
001:>h:10.0
002:>h:10.0
010:<BBhhh:1:1:1:1:1:b1:b2:b34:b56:b78
020:<hhhh
031:<hhhh:1:1:1:1:b12:b34:b56:b78
041:<hhhH:1:1:1:1:b12:b34:b56:b78
051:<hhhh
060:>h:10.0:BatTgtV
070:<hhhh
181:<LL:1000.0:1000.0:InvV:GrdV
191:<HhHh:1:1:1:1:b12:b34:b56:b78
1B1:<LL:b14:b58
1C1:<HHHH:1000.0:1:4.0:1:InvHz:b34:InvAbsW:b78
1E1:<ll:1:1:b14:b58
1F1:<HHHH:1:1:1:1:b12:b34:b56:b78
201:<hhhh:1:1:1:1:b12:b34:b56:b78
221:<HHBBBB:1:1:1:1:1:1:b12:b34:b5:b6:b7:b8
581:<LL:100000.0:100000.0:b14:b58
601:<LL:100000.0:100000.0:b14:b58
 

etatdiysolar

New Member
Joined
Jun 29, 2021
Messages
11
Ok, so maybe it does charge in lithium mode, not sure why I thought otherwise... madsci1016 does charge via PV in DC side and not use the SI.

Toms, if you have any SI settings suggestions or info on SI setup it would be appreciated...

I will try to get the RPi working with can bus, but I'm not familiar with RPi linux/ python code... so it may take a while..
 

toms

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Joined
Jul 24, 2020
Messages
749
I see my SI8.0H to lithium mode, then all the battery parameters are set in the BMS.

The Sunny Island is controlled by the BMS.
 

MurphyGuy

Solar Addict
Joined
May 20, 2020
Messages
688
Hello Hedges (and everyone), I have been considering the purchase of 4 Sunny Island inverters through eBay. I currently own two Victron inverters and I am pretty comfortable with them and they seem to be working well. The reason I'm considering the purchase of the Sunny Island inverters is because I need more power than the two 3kva inverters I currently have. I could go with a much bigger Victron, but eventually this inverter setup will be in shop building, which is currently off grid but might in the future have a grid connection (I'd like the option either way). Victron does not currently have much to offer in the US from a code compliance perspective. My current inverters probably do not have all of the associated US certifications, and so therefore they are setup in a mobile fashion, similar to using a generator to power a building. I'd like to permanently install the future inverters and pass code compliance certifications (I didn't find anything that seems to indicated that the Sunny Island couldn't pass code compliance in the USA).

I've read posts about AC coupling with Sunny Island and having some issues with inverter models from SMA, but it appears you were able to work through these problems.

Hedges (or anyone with experience) based on experience, would you do it all again and repurchase your Sunny Island inverters, or would you look elsewhere?

I'm really spoiled by the Victron central control, the Cerbo GX device, etc. The Sunny Island website isn't as user friendly as the Victron site in my opinion, and I'm having some difficulty figuring out if I can bridge an older inverter model like the Sunny Island into the SMA tech stack that connects to the internet. Do you know if it is possible to make the Sunny Island connect to the SMA Data Manager M by using an SMA Communication Gateway? https://www.sma.de/en/products/monitoring-control/sma-com-gateway.html

Thanks for your time.

Dan

I would absolutely do it again.. wouldn't do it any other way.. In fact, if I could find the same ebay deal again for the inverters, ($1100 each), I'd buy two more just as spares.
 

etatdiysolar

New Member
Joined
Jun 29, 2021
Messages
11
You'll never see that deal again because the billion dollar pozi scheme has been fully liquidated now.... I also wish to have got a few extras..

Ok, I was sorta right, I can't use lithium mode, because the RPi is not doing the job of battery management, madsci1016 was just passing SOC from the smartshunt and his DC charger was doing all the management, voltage levels, current control, etc...

I'll have 12 battery packs each with thier own BMS when done I'd have to rip out all the BMSs and no plans to do that... dalklein, if you're building your own batteries with REC then you should be good.. , running in VRLA mode seems to be working for me.
 

daklein

Solar Enthusiast
Joined
May 8, 2020
Messages
58
What are your BMSs on each of the 12 packs? If they communicate, at least what their voltage is, that would be useful. I wouldn't remove those bmss if they're working fine at a pack level. The smart shunt would measure the total battery bank current, and voltage and report that to the SI via the RPi.

With the SI in lithium mode, the RPi being the source of bms messages to the SI, should be able to control an AC coupled system by changing the max charging power (lowering it). That should cause the SIs to raise the AC1 freq and kick off any GT inverters that are backfeeding AC coupled power. And, as the battery bank voltage gets too high or low, change those power limits also. Need to be careful to double check that things work as intended though. Plenty of room for errors, like if the RPi locks up.

Using VRLA mode should work fine most of the time. The trouble might be with the SIs estimate of SOC based on voltage and current counting. Every now and then it will suddenly decide that SOC is off a bit and reset it up or down, and that could shut your system down. madsci reported that type of issue.

Not using REC. I'm staying with the forklift FLA until they die, I hope 10 years. I have separate lithium packs that I charge either direct from solar (Midnite 250 CC), or from AC:DC chargers as load dump with excess solar. I have 9kwhr working with two 36v 10s packs in parallel in an Electrak, and setting up 4 stationary 48v 14s packs for about 13kwhr more. I discharge the lithium banks with old enphase microinverters, AC coupled back to the SI AC1 (the house). The JBD bmss on those packs talk to the RPi. The RPi controls the AC:DC charging and the microinverter discharging, aiming to keep the FLA just floating full overnight, except big short term loads. There are 3 banks not directly connected to each other: the 48v FLA, 10s 36v Leaf modules, and 14s 48v Leaf modules. It's not the simplest system, or something I'd recommend, but, it's kind of fun & neat & cheap. The old enphase micros were nearly free, the Leaf modules are the old pack I removed from our car, and the DC Solar trailer was cheap.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,435
SI 6048US is UL listed, meets US codes. The European 8.0 model isn't in the US yet, so wouldn't meet code.
Since UL-1741SA became the standard, Sunny Island doesn't meet that, but I think that just means it can't be the inverter which is backfeeding grid (i.e. with DC coupled PV as power source.) It should still be a acceptable as an inverter/charger to provide UPS function.

I'm quite happy with what I got, glad I got a pallet of them during the liquidation sale. Otherwise I would have installed fewer for cost reasons.
I do monitoring locally, not connected to internet.

Compatibility issues I've had are older model Sunny Boys that don't reduce power output in response to frequency, and SB 10000TLUS which is supposed to in "backup" mode but only does so in "offgrid" or "island".
Other issue is when powering a VFD (for 3-phase motor), Sunny Boy gets upset when connecting. Cheap VFD aren't power-factor corrected.

I use a small AGM bank. I should wire more relays to disable loads based on SoC, grid status, time of day. Power failures are infrequent, and some load management I do manually.
 

etatdiysolar

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Jun 29, 2021
Messages
11
I plan to use a cheap 1 to 3 phase converter for an old lathe, would that give the SBs the same problem, what sort of problem did you see?

How do you handle not enough battery capacity, I'm in the same boat as I wait for delivery. Thinking now that I will trigger connect to grid with low SOC of say 25% then charge up to say 50%, this may happen a couple time in the night until the sun comes up and fully charges the li batteries... ???
 

Hedges

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Joined
Mar 28, 2020
Messages
8,435
My PV exceeds consumption during times of good sunlight, so battery recharges from night before and stays floating. Battery provides any needed starting surge.

If you have grid available, probably just let SI use it to keep battery full except during expensive time of use.
For off-grid operation, ought to have batteries able to carry load until sunup. Shutting off fridge/freezer and the like would help. Ideally with a relay box that also has a thermostat to re-enable in event temperature rises too high.
For lead-acid, default is load-shed house at 70% DoD automatic reconnect at 50% DoD. Shut down inverter if 80% DoD reached (then you have to recharge somehow and manually restart.) Your lithium DoD settings probably differ; I don't know if that is even set up with BMS communication.

With VFD running and Sunny Island forming the grid, when 10000TLUS wakes up it occasionally says "IGBT Error". When waking up 5000US says, "relay fault". If they are already running when VFD is started, it is OK.

What we want is a VFD with near 1.0 power factor. Some switching power supplies actively stuff cancelling harmonics into the line. Others have a switcher on the line side input to synthesize a sine-wave current draw.

Something I mean to try is putting an induction motor after the breaker feeding my VFD. Maybe a rotating mass will hold up voltage when the diode/rectifier front end tries to clip top off voltage waveform.
 

etatdiysolar

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Jun 29, 2021
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Wonder if electric instant water heaters do the same thing and stuff harmonics into the line? I have a couple that pull 13kw, so I wonder if they may cause trouble once I switch them onto the SI grid soon... hmm.
 

Hedges

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Mar 28, 2020
Messages
8,435
Not if they are just a big resistance heater. But if they support variable flow with regulated output temperature, they have to do something. Could be a "light dimmer" which probably isn't as bad as using a diode to place a capacitor across the AC line.

If you want PV/inverter system, it is likely you have surplus power for a period of time and would be better off diverting AC to a storage water heater. Store that energy in H20 instead of Pb of Li.

So you already have the instant-on heaters. Maybe feed those from grid and put a storage heater before or after the instant on? (check its specs on inlet temperature range.)
 
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