DIY battery system for SMA Sunny Boy

[Eran]

Thank you so much Hedges,

I change The Max AC Charge current to 20.100 AC I simulated a grid outage and seemed like it worked. I do log in to the system VIA the LAN and WLAN. and Yes it 32 mA is a ground-fault limit.


I did change this value back its original value which was 60A from 25A which i set, but neither should trigger the ground limiter. Isn't it?

 

[Hedges]

10's of amps of battery charge current shouldn't affect ground-fault circuit, which measures current out through "Line" and back through "Neutral" to ensure they are same (if different, current is leaking into ground.)

I don't have GFCI as part of my system.
In the U.S. we have 5 mA GFCI outlets for wet locations like kitchen/bath/outdoor.
Our grid connection has a Neutral which is connected to ground, usually at our meter.

In Europe, some utility service has no ground connection to Line/Neutral, and a 30 mA GFCI is used for the entire building.

Is GFCI built into your Sunny Island? Or is Sunny Island tripping a GFCI in your house panel?
EMI filters typically dump a couple mA into ground due to capacitors they have to suppress RF emissions. That's something I measure and address in my day job.
Grid Tie inverters like Sunny Boy are transformerless these days, and PV panels have some capacitance to ground; not galvanically isolated by the GT inverter, could affect it.
Sunny Island (at least my US model) has floating battery, and allows either positive or negative ground. That is galvanically isolated from AC, but could carry some capacitive coupling.

Disconnecting all AC loads and all AC and DC coupled PV or other generation should narrow the issue to just Sunny Island and battery.
Ground chassis of Sunny Island. Also try disconnecting all communication ports.

 

[Eran]

Ones again Thank you @Hedges for taking the time to answer my question.

The SI does not have GFCI inbuilt in, but I have used GCFI in the Grid line coming in to the SI. As ground fault protector. and also goes through a AC circuit breaker. I did pull off all the loads and try its trips on its own. My guess is faulty GFCI unit or what you Advised, I am going to replace it with 100mA GFCI else or altogether remove it. But ill update you when I narrow down on the issue

Mine as well has floating Battery only thing i didnt disconnect was the com lines let me try doing that.

I did add my plant to the sunny portal yesterday after trying for some time.

Thank you gain hedges

 

[mudman455]

Hedges, Can Sonny Island SI6048-US net meter here in the US? Also what Lithium batteries work best, and how about server rack batteries? Thank You Randy

 

[Hedges]

Sunny Island is capable of doing that that, but doesn't meet newer newer codes, which require features it lacks.
It used to be on California Energy Commission's approved list of inverters. If you drive battery with DC coupled PV to a higher voltage than SI wants, it can export that.
It is no longer on the list since Rule-21 and UL-1741-B functions were added.

Presumably it would be allowed as battery backup, a UPS, with GT PV downstream.

I've only used lead-acid batteries. Some people use various lithium batteries open-loop. Some use REC BMS for closed-loop.
SMA lists various supported batteries including from BYD.

https://files.sma.de/downloads/SI-LiIon-TI-en-48.pdf

 

[mudman455]

Sunny Island is capable of doing that that, but doesn't meet newer newer codes, which require features it lacks.
It used to be on California Energy Commission's approved list of inverters. If you drive battery with DC coupled PV to a higher voltage than SI wants, it can export that.
It is no longer on the list since Rule-21 and UL-1741-B functions were added.

Presumably it would be allowed as battery backup, a UPS, with GT PV downstream.

I've only used lead-acid batteries. Some people use various lithium batteries open-loop. Some use REC BMS or closed-loop.
SMA lists various supported batteries including from BYD.

https://files.sma.de/downloads/SI-LiIon-TI-en-48.pdf

Thank you

 

[daklein]

Also what Lithium batteries work best, and how about server rack batteries? Thank You Randy

Another SI6048 lithium battery bms option is a victron shunt with a raspberry pi running venus os, which can talk to the SI CAN bus reporting SOC to keep SI happy and operating properly. https://github.com/madsci1016/SMAVenusDriver and search in the forum here for @madsci1016 posts (the really long SI6048 inverter thread might be where it's discussed.

 

[etatdiysolar]

Anyone besides madsci1016 got that working? He doesn't charge with the SI.

 

[Hedges]

AND ...

I just bought more AGM. Used, supposedly not heavily.
24 pieces of 6V 250 Ah.

I'll use that for three Sunny Island systems of 12kWh (gross) each, or one 12 kWh for my planned 2x SI split-phase system and maybe 24kW for my existing 3x SI 120/208Y three-phase system (which presently has 5kW of old, tired batteries.)

The batteries should last a decade of nightly 15% cycling (1800Wh, 150W average which leaves 100W average draw for night time loads after 50W for 2x SI.)
But for now, they're just grid-backup so will float except during grid failures. OK to use 70%, 8400Wh, less frequently.