sma sunny island thinks battery voltage is low

[ripvansparky]

Oi! I have two sunny islands running off my diy battery with batrium bms. My shunt died, so I had to swap out the bms for an older version with working shunt. Now my SI's wont make power, just throw code f213? low battery voltage. The bms is communicating properly, the SI displays proper SOC and BV but is being stubborn as a mule about it. I've spent hours trying everything and searching online with no joy. Soooo, I'm hoping someone here has some insight. Honestly these things are almost a boat anchor, they are so outdated.

 

[kommando]

Check all your connections between batteries and the SI's, use a multimeter to check where the V drops. With the capacitor inrush is the BMS shutting down discharge, if so use a pre charge resistor.

The BMS may be reporting its V and the SI displays it but if the SI's internal voltmeter does not also see the V then it will not startup.

 

[ripvansparky]

Yeah I have checked everything. I use a precharge resistor too. It's absolutely baffling.

 

[kommando]

Check the internal DC breaker is working ie the one with the lever on the front cover on the master.

 

[ripvansparky]

It is, these are brand new, I only have been using them off and on a couple of weeks as I have been trying to integrate them to my system. It has been extremely difficult, unlike the growatts which are soooo easy to use. Other than that one time the autotransformer breaker tripped and almost burned down my house. That's why I decided to get fancy and go with the most over engineered German crap I could find. sorry to rant, I'm annoyed lol

 

[kommando]

Well when the possible has been eliminated then you need to consider the Impossible.

But first try this, there are three protection SOC's, for lithium I set at low SOC's eg 2 3 and 4% but by default they get set to lead acid values which are much higher. If the BMS reports SOC's below these % the SI shuts down. So check these and set them to 2,3 and 4.

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If that does not work.

Revert back to the last working setup, ie the Batrium with bad shunt. Assuming the shunt is used by the Batrium to calculate the SOC then the SI will not be bothered, it charges to the BMS set V and ignores 100% SOC as a signal to stop charging. If that works then the issue is in the latest BMS with working shunt.

 

[ripvansparky]

I also tried swapping the slave and master. I tried setting the protection values super low as well. I'll try swapping back. thanks for the input!
It's just baffling that it keeps throwing the fault but all the meters and communication are proper

 

[kommando]

Check the firmware, your SI's may be 'New' but still have old firmware and the first Lithium firmware had bad canbus comms.

For the SI4048US latest firmware is

https://files.sma.de/downloads/SI4548-US_6048-US-7304_7300.zip

Also update the Batrium firmware.

 

[ripvansparky]

Yeah I updated them before commissioning them. It must be something not right with the 1st gen Batrium coms. Im giving up until I can order a new shunt from them, then hopefully it will work. If not, well who knows??

 

[kommando]

SMA made a change to the Canbus messages during one firmware update which stopped the Midnight Chargers emulating SMA chargers. Neither Midnight or SMA fixed the issue so I have the opinion the SMA Canbus docs do not tell the full story and there are hidden errors/messages.

See post 12

Thread 'Sunny Island 6048 Midnite Classic Rec BMS'

Sep 18, 2023

So I’ve been PMing with @Hedges a bit about SMA systems. Very grateful for the contributions and I think I’d like to expand to others for more insight as well.

SMA Sunny Island does not seem designed to handle Lifepo4 banks. To mitigate, it appears that many utilize the REC BMS for lithium comms
Every thread I’ve found so far, shows this working with AC coupling with Sunny Boy.
Hedges brought up the sunny boy as well, so I guess maybe I need to take this under more serious consideration
Unfortunately, my pea brain can only absorb so much, so often. And so it’s still stuck on DC...

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