Sunsynk inverter doesn't connect to Hubble BMS using BMS CAN bus

[MarcFe]

Hi everyone,

We've recently set up our residential solar system here in Muizenberg, using 10x 455W panels in two arrays, a 5kW Sunsynk inverter and a 5.5kWh Hubble AM2 battery.

I set up a Raspberry Pi with the Solar Assistant software which connected very easily to the Hubble battery, using the RS232>USB converter cable from https://solar-assistant.io/. When I tried to connect the Sunsynk inverter to the same Raspberry Pi, it wouldn't accept its signal – it threw a "CRC Error" and didn't show the inverter in the dashboard.

Eventually I figured out that it had to do with the battery settings of the inverter – I set it to "Lithium" and "RS485", which I assumed would give me a solid connection between the battery and the inverter. It turned out that the battery settings on the inverter can't be set to RS485, otherwise the signal from the inverter doesn't make it through the BMS485 port, where the Raspberry Pi, running the Solar Assistant software, was connected. Once I set the battery in the inverter settings to communicate over CAN, it suddenly worked.

I'm very pleased about the Solar Assistant software running on my RasPi, it's super fast and has a well done user interface. 

But, when I now open the SOLARMAN app – which is connected through the wifi dongle of the Sunsynk inverter (see photo), I still can't get a connection between the inverter and the battery. I had a few suspicions along the way, but none of them have solved the problem, so far. They were:

• Battery / inverter firmware aren't up to date enough – Sunsynk and Hubble couldn't talk via BMS back in the day
  • Installer told me that firmware is up to date, not sure if this is the case. Sunsynk support told me it's definitely possible to read Hubble BMS on Sunsynk
     
• I am using the wrong cable. Does it have to be a crossed Cat5 ethernet cable or some other weird pin layout?
  • The installer said it will work with just a regular Cat5 ethernet cable
     
• The inverter must be either restarted or set back to factory settings, so it can start up the very first time with the Hubble battery attached to the BMS CAN bus
  • I find this hard to believe, I would have thought that the BMS CAN bus from the inverter can easily ready from the battery even if plugged in later

Any thoughts on this? Is it worth doing a proper reboot of the Sunsynk inverter? If so, how does this work?

Currently, the Solar Assistant software gives me very accurate details about the battery. I see the SOC percentage is very different from what the SOLARMAN software reads. My fear is that I am currently telling the inverter to charge the battery based on Lithium methods, but it can't, as it's not able to read what the battery is saying. Maybe this is not an issue, but often the SOLARMAN software discharges the battery down to 80% (which I programmed in the work mode) but the battery SOC in the Solar Assistant app tells me it's actually down to ~46% or something like that.

Thanks everyone, I hope this made sense,
Marc

[TimCam]

28 minutes ago, MarcFe said:

I am using the wrong cable. Does it have to be a crossed Cat5 ethernet cable or some other weird pin layout?

• The installer said it will work with just a regular Cat5 ethernet cable

 

Look on the Hubble website with reference to SunSynk CAN connection. All settings are there, and the correct pin-outs.

The supplied cable is only for AM-2 to AM-2 battery communication, not to be used to any inverter.

 

Welcome to the solar family, and hope you have many happy years with your setup.

Good looking setup, and choice of components.

 

Edited December 6, 2021 by TimCam

[MarcFe]

26 minutes ago, TimCam said:

Look on the Hubble website with reference to SunSynk CAN connection. All settings are there, and the correct pin-outs.

The supplied cable is only for AM-2 to AM-2 battery communication, not to be used to any inverter.

 

Welcome to the solar family, and hope you have many happy years with your setup.

Good looking setup, and choice of components.

 

Thanks for your quick reply, TimCam.

Oh alright, I did have a look at that, but wasn't sure how to get / create such a cable...

Just to confirm, you are saying with this cable layout, it should work between Sunsynk BMS CAN and Hubble CAN?

https://www.hubblelithium.co.za/sunsynk-hubble-setup.html

[TimCam]

That's the the one, and double check the dip switches too.

 

[MarcFe]

8 hours ago, TimCam said:

That's the the one, and double check the dip switches too.

 

Thanks, I will try to get a cable made to match the drawing posted above. @TimCan, does it make a difference then, not using a normal cat5 cable – as in, are those left out cables essential? I didn't realise that's the case, but if so, let's find out soon once I get hold of the right cable :).

I changed the DIP switches from "untouched" (0 0 0 0) to "master" (1, 0, 0, 0) for now and can see this in the SOLARMAN app when going on the inverter device screen's battery tab:

Is this all I should see, or do you think the battery and the inverter are still not communicating properly over the BMS CAN?

Thanks for your help, and also for the kind words about our setup – I'm particularly happy having 2 MPPTs and two arrays of panels facing east/west, it's been great so far and I'm keen to take it further with home automation, solar geyser relays (heat when there is sun) etc. using the Solar Assistant software's MQQT integrations.

Thank you,
Marc

[MarcFe]

Update: It's now working!

Thanks again, TimCam, the hint with the DIP switches solved the issue. It's possible to use a normal cat5 ethernet cable to establish a connection between Sunsynk inverter and Hubble AM2 battery. If you use a single Hubble battery just make sure the DIP switches at the bottom of the battery are set to Master (1, 0, 0, 0) and the inverter will be able to read the BMS data and displays them in the LiBMS dashboard (see photo).

Again, for me it was important to also have the Solar Assistant software running properly on my Raspberry Pi, why I needed to connect the battery to the inverter using the BMS CAN (inverter) to the CAN (battery) ports. The battery settings on the inverter hence must also say "Lithium, connection through CAN", not RS485. Hubble and Sunsynk can apparently communicate through both channels, but if you choose RS485, the Raspberry Pi with the Solar Assistant software won't get a readable signal from the inverter.

For the Solar Assistant software to work, I connected both battery and inverter straight to the Raspberry Pi, using the USB cables from solar-assistant.io, which work perfectly well. The RasPi 4 delivers data every 1-2 seconds which is amazing

Now it's all – hopefully – working as good as it can be. Thanks again, TimCam.

[TimCam]

Great to see your setup working to your satisfaction, and with your monitor software too.

The satisfaction of been independent even through load-shedding is great, and cutting down on the electricity bill is priceless.

 

[MarcFe]

Just now, TimCam said:

Great to see your setup working to your satisfaction, and with your monitor software too.

The satisfaction of been independent even through load-shedding is great, and cutting down on the electricity bill is priceless.

 

Yes, I agree. We've been running a small inverter/battery backup for our studies for years, but it was about time to replace the AGM batteries – so we decided to go Lithium and solar instead. Super happy about the step, and yes, saving electricity is obviously... good :).

[Mervyn Cookson]

Hi all. 

I have installed a Sunsynk 8.8kw with 2 x BSL BATT 5.1kwh batteries in parallel. One master and the other slave. Connected the battery link cables and the CAN cable between the master battery and inverter . But I can't see the BMS info on Solarman  . No PV installed on this system. Just a back up. 

I connected up a 3P 12kw Sunsynk recently with 3 Hubble 5.5kwh batteries in parallel in the same way and can see BMS info on Solarman. Pv installed on this one. 24x 455w panels. 3 arrays as the Sunsynk has 3 MPPTs.

Please help. 

 

[Deonlr]

Just wanted to say thank you, I've been struggling for a day to get Hubble BMS to connect, was about to make a custom cable as last resort.  Turns out it was just the Master setting on the DIP switches.  You guys are live savers.