Troubleshooting SMA and REC - Mostly (all?) Solved

[SilverbackMP]

It should have a Gen option,

View attachment 188702

I found it and got it working. Thanks!

We are assuming that the values are per Sunny Island. Is that what you are finding? So if I have a 240v split phase 30kw generator (150 Amp @ 240), the settings under 234 03 (GN CurNom) should be 62.5 amps. 234 01 (GnVtgMin) and 234 02 GnVtgMax should remain 80-150v (to target 120v) and that’s what they are seeing off the two legs. Does that make sense?

This is the kind of irritating shit about SMA…you gotta guess about this kind of stuff unless you find it in a special flyer or the occasional 15 year old video.

 

[1201]

No external grid.

I thought that setting might be named so due to German to English and SMA’s ability to talk around any issue/setting inst

I found it and got it working. Thanks!

We are assuming that the values are per Sunny Island. Is that what you are finding? So if I have a 240v split phase 30kw generator (150 Amp @ 240), the settings under 234 03 (GN CurNom) should be 62.5 amps. 234 01 (GnVtgMin) and 234 02 GnVtgMax should remain 80-150v (to target 120v) and that’s what they are seeing off the two legs. Does that make sense?

This is the kind of irritating shit about SMA…you gotta guess about this kind of stuff unless you find it in a special flyer or the occasional 15 year old video.

It's per sunny island.

My gd current nominal is 50a and my sunny islands will pull 12kw from the grid so I know that it is per sunny island.

Also, the voltage is 120v so when I set my voltage to 122v on the master, the total voltage for 2 phases shows as 244v

 

[Hedges]

SI multi-function relay has option "AutoGn Automatic generator request The generator is automatically activated due to set
criteria (see Section 14.1.5 "Automatic Generator
Operation", page 123)."

You could use that to signal you when manual generator needs to be started.
I guess it could provide an additional load-shedding control as well.

I would hope everything require for care and feeding of SI could be found by RTFM.

"Value for parameter "234.03 GnCurNom"
A sensible value for parameter "234.03 GnCurNom" is approximately 80% of the maximum
generator current for each line conductor."

"If the parameter "234.15 GnCtlMod" is set to CurFrq, the generator is also limited at frequencies
lower than the nominal frequency (parameter "234.04 GnFrqNom"). This function can be used if the
full generator power is not always available and you want to prevent the generator from being
overloaded. The default setting is only intended to control the nominal generator current.
If the current set using the parameter "234.03 GnCurNom" is not sufficient for powering the loads,
the battery provides support ("real generator support").
The Sunny Island provides all the required reactive power."

So that one appears to be per SI, whether single-phase 4p configuration or split-phase 2p2s.

I remember setting larger values than 56A for grid current, up to 112A with two SI in parallel.
Could be that is due to quick-start menu, where we apparently type in the total current. But the parameters accessed in other menus are per inverter?

"
GenGrid:
– Maximum generator current (0 A - 224 A), default setting: "16 A"
– Generator interface (Manual, GenMan, Autostart), default setting: "Autostart"
– Maximum grid current (0 A - 224 A), default setting: "16 A"
"

It's per sunny island.

Except during quick-start, it seems.

 

[SilverbackMP]

SI multi-function relay has option "AutoGn Automatic generator request The generator is automatically activated due to set
criteria (see Section 14.1.5 "Automatic Generator
Operation", page 123)."

You could use that to signal you when manual generator needs to be started.
I guess it could provide an additional load-shedding control as well.

I would hope everything require for care and feeding of SI could be found by RTFM.

"Value for parameter "234.03 GnCurNom"
A sensible value for parameter "234.03 GnCurNom" is approximately 80% of the maximum
generator current for each line conductor."

"If the parameter "234.15 GnCtlMod" is set to CurFrq, the generator is also limited at frequencies
lower than the nominal frequency (parameter "234.04 GnFrqNom"). This function can be used if the
full generator power is not always available and you want to prevent the generator from being
overloaded. The default setting is only intended to control the nominal generator current.
If the current set using the parameter "234.03 GnCurNom" is not sufficient for powering the loads,
the battery provides support ("real generator support").
The Sunny Island provides all the required reactive power."

So that one appears to be per SI, whether single-phase 4p configuration or split-phase 2p2s.

I remember setting larger values than 56A for grid current, up to 112A with two SI in parallel.
Could be that is due to quick-start menu, where we apparently type in the total current. But the parameters accessed in other menus are per inverter?

"
GenGrid:
– Maximum generator current (0 A - 224 A), default setting: "16 A"
– Generator interface (Manual, GenMan, Autostart), default setting: "Autostart"
– Maximum grid current (0 A - 224 A), default setting: "16 A"
"



Except during quick-start, it seems.

Thanks Hedges. My electrician might be stopping by later so I’ll show him. My head hurts. Lol.

 

[SilverbackMP]

One thing other thing that concerns me…when I had the generator on, the FIVE batteries were at about 85% SOC, were only charging with 5kw (according to the BMS). Now if I have the C charging coefficient set at 0.25, and they are 230AH batteries, and they should be able to take in in around 14-16kw. Does that sound right?

 

[kommando]

What voltage are the batteries at is more important to the charge rate than the SOC, what is the battery voltage showing at the 5kw charge rate.

 

[SilverbackMP]

What voltage are the batteries at is more important to the charge rate than the SOC, what is the battery voltage showing at the 5kw charge rate.

I think around 3.36 / 53.76 but I will run it again this afternoon (when my electrician stops by).

 

[kommando]

You are closed loop but being SMA that still leaves the question of whether the charge rate is set by the SI or the BMS. Only looking at the data will show you that, once you know which equipment is setting the charge rate you should be able to alter the setting.

 

[1201]

One thing other thing that concerns me…when I had the generator on, the FIVE batteries were at about 85% SOC, were only charging with 5kw (according to the BMS). Now if I have the C charging coefficient set at 0.25, and they are 230AH batteries, and they should be able to take in in around 14-16kw. Does that sound right?

Yes. About 14kw.

There are several settings in the sunny island that can limit how much charge is going into the batteries.

You also have to subtract the loads as the generator/pv are both charging the batteries and supplying the loads at the same time

 

[SilverbackMP]

Yeah, it’s only charging around 5.5 kw. Other loads on the generator aren’t anymore than 2kw.



Sigh….let’s see if I can run down this setting.

 

[SilverbackMP]

Yes. About 14kw.

There are several settings in the sunny island that can limit how much charge is going into the batteries.

You also have to subtract the loads as the generator/pv are both charging the batteries and supplying the loads at the same time

Ah, I see you’ve likely already identified the problem in that attachment. Thanks for that. All of that reads like it’s old programming for lead acid and it needs to be adjusted for lithium.

 

[1201]

What is your gen cur nom set at? The default is 30a

So about 7.2kw for two sunny island. Subtract 2kw for your loads and leaves about 5kw

 

[SilverbackMP]

What is your gen cur nom set at? The default is 30a

So about 7.2kw for two sunny island. Subtract 2kw for your loads and leaves about 5kw

61 Amps. Just under the 62.5a (250a @120v from the 30kw, divided by four (per Sunny Island).

 

[1201]

61 Amps. Just under the 62.5a (250a @120v from the 30kw, divided by four (per Sunny Island).

Ok so if must be something else then. Please let us know what you find.

 

[SilverbackMP]

61 Amps. Just under the 62.5a (250a @120v from the 30kw, divided by four (per Sunny Island).

Maybe that one should be set for all four inverters? I don’t think so.

This also threw me for a loop:


From here: https://www.sma-sunny.com/en/generator-settings-on-the-sunny-island-for-off-grid-systems/

Assuming they are referencing gen cur nom set.

Whereas it said 30A default in the manual and it’s was actually set to 30A.

Maybe I set it too high? And it’s ignoring it. The 50A figure makes more sense given specified capabilities.

 

[1201]

Maybe that one should be set for all four inverters? I don’t think so.

This also threw me for a loop:

View attachment 188831
From here: https://www.sma-sunny.com/en/generator-settings-on-the-sunny-island-for-off-grid-systems/

Assuming they are referencing gen cur nom set.

Whereas it said 30A default in the manual and it’s was actually set to 30A.

Maybe I set it too high? And it’s ignoring it. The 50A figure makes more sense given specified capabilities.

Hmm, that page provides a hint- do you have the generator output feeding all four sunny islands? ( I think you have four?)

 

[SilverbackMP]

Hmm, that page provides a hint- do you have the generator output feeding all four sunny islands? ( I think you have four?)

Yes, it is. Yep, four sunny islands.

 

[SilverbackMP]

So I adjusted 222 01 Bat Chrg Cur Max to 250 A.

Was able to double the amount watts and amps the batteries were charging with:


I am thinking that I might be limited by the number of batteries now? Might be able to take in more power at .25C as I add more…

In a subsequent test, I also adjusted 234 03 Gen Cur Nom to 112 A.

The 112 A is based on this:



but it didn’t have an direct effect on the battery charging with current setup.

I would think that two sets of two Sunny Islands could handle 224 A …but apparently not…as it would not let me go higher than 112.

Edit…I bet that means 112 A per SI pair / 120V leg. Maybe?

 

[1201]

Making progress, that's great.

If you raise battery charging current max even further, like 500a, what happens?

 

[SilverbackMP]

Making progress, that's great.

If you raise battery charging current max even further, like 500a, what happens?

Will try next time I run the generator - which will be several times today. Had a hell of a time getting it started after a -16 F night and no block heater. So I will try to keep a bit of heat in it…and will buy a block heater and a dedicated battery tender now that we have some power to spare. But I digress.