Cerbo GX Commissioning

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brucevanderbilt asked Feb 8, '22

Cerbo GX Commissioning

I've installed a pair of multiplus 12/3000/120 (in parallel), with Lynx Ion Smart BMS, Cerbo GX, and 4x Victron Lithium 330ah batteries. I've udpated the firmware on all these components. The Multiplus firmware is v490 and the Cerbo GX is v2.81. While I have solar chargers and an SBP, I have not installed them yet in favor of working out all the kinks of the basics before adding on.

As I’m working through my configuration, there’s a few things that do not seem to be working properly.

1) I’m not seeing SOC on my Cerbo GX. When checking the BMS in Victron connect, it shows 100% state of charge. I believe the BMS is working properly because it balanced the batteries from the start and also passed initial testing of disabling the Multipluses and opening it’s contactor when I disconnected the BMS cable from a battery. The manual indicates that SOC should be shown after synchronization, but no luck so far (after several absorption runs of 2 hours)

2) I don’t see the BMS in my device list. Should I?

3) I don’t see the BMS as a device option under Battery monitor. Should I? NOTE: It does, however, show up under the VE.Can port settings of the Services menu.

4) And finally, this is more of a question on DVCC. The manual seems to talk more about settings for other manufacturers batteries than for the Victron Batteries. There’s no mention at all for Victron Smart Batteries. Here are my current settings. Could these be introducing an issue with the SOC not appearing on the GX? For my configuration, should I enable SVS, STS, and SCS?

Thank you for your help in advance!

cerbo gx BMS

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Stefanie (Victron Energy Staff) answered · Feb 08, 2022 at 07:22 PM

Hi @brucevanderbilt,

the problem I see is that your Lynx Smart BMS is not showing up at all. This explains all of the issues you mentioned above.

Can you please post images of your installation, especially how you have connected the Lynx Smart BMS to your GX device.

About DVCC: once the Lynx Smart BMS is installed and correctly detected by your GX device, DVCC is forced on automatically.

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Matthias Lange - DE answered · Feb 08, 2022 at 07:24 PM

Is the BMS connected to the correct port on the Cerbo GX (VE.Can not BMS-Can)?

Edit: och menno Stefanie, hehe. :D

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Stefanie (Victron Energy Staff) ♦♦ commented · Feb 08, 2022 at 08:01 PM

@Matthias Lange - DE

Yeah, sorry Matthias ;-)

@brucevanderbilt

Yes, make sure the Lynx Smart BMS (it's not a Lynx Ion!) connects to VE.Can port of the GX device and also make sure it's properly terminated. See the manual for all the info.

Once connected, you should see it in the devices list as well as in Settings/Services/VE.Can port. Ignore the Can-bus profile name.

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Stefanie (Victron Energy Staff) answered · Feb 16, 2022 at 06:35 AM

Hi @brucevanderbilt,

IMO this should have been an entirely new question in my opinion as it is a completely new subject.

As you already mentioned, bulk, absorption and float have a different meaning in a lithium system, especially in a system where the BMS is controlled by the Cerbo GX in DVCC mode. It is all about charge voltage limit (CVL) and charge current limit (CCL) with respect to the chargers.

The Lynx Smart BMS determines CVL and CCL and the Cerbo GX controls the chargers (those that are DVCC capable like MPPT and MultiPlus). In this respect, bulk, absorption and float no longer play a role at all. Although you have to set the parameters for Lithium batteries in your chargers, they will be ignored because of DVCC.

You have to get used to the new terminology or wait for Victron to go back to using the old terminology despite everything.

2. As far as I know, CVL stays at 14.20V until the absorption phase time set in Lynx Smart BMS (defULT = 2h) is elapsed.

3. This is normal. See explanation above.

4. It has nothing to do with DVCC. The behavior of your installation is similar to what I also notice in my system. And this has been going on for 1.5 years now.

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Modifications Space

Node Red Space

Answer 1 · 2022-02-08T21:19:04Z

brucevanderbilt answered · Feb 08, 2022 at 09:19 PM

@Stefanie @Matthias Lange - DE You guys are amazing. I get so turned around on nomenclature of components BMS Can vs VE.Can, Lynx Smart BMS vs Lynx Ion vs VE. Bus BMS, etc. Both your answers are very helpful.

-Mathias, I had the BMS plugged into (and terminated) the BMS-Can port vs the VE.Can port. Also, thank you for letting me know to ignore the Can Bus profile name under services, because it shows Lynx Ion BMS, which confused me about the nomenclature. But, yes the Lynx Smart BMS shows up there now.

-Stefanie, Thank you for the DVCC information. You are absolutely correct, DVCC is now showing up as "Forced On."

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Stefanie (Victron Energy Staff) ♦♦ commented · Feb 08, 2022 at 09:25 PM

Glad it's working now.

For the Lynx Ion BMS in VE.Can port: it's only the CAN-bus profile. But I understand how confusing this can be.

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Answer 2 · 2022-02-15T21:07:08Z

brucevanderbilt answered · Feb 15, 2022 at 09:07 PM

@Stefanie @Matthias Lange - DE . I've had a few days to play around with the system to observe behavior. I still haven't hooked up the MPPTs as I want to make sure the BMS, batteries, and Multipluses are all playing well together. It seems the BMS is performing flawlessly and cerbo accurately reporting the state of things.

However, with no prior experience, I'm not sure if I'm observing the correct charging behavior. For testing purposes, I have the batteries at 100% SOC and multipluses set to the recommended lithium settings of absorption voltage at 14.2, float voltage at 13.5, and then charge current 90A (Note, i have 2 in parallel) and Absorption time at 1 hour.

I manually switch off the Multipluses and BMS. I power them back on to observe behavior.

1)The Multipluses run in bulk supplying 180 amps which slowly diminishes down to about 5 amps after about 15 minutes. Then switches to absorption. This seems normal but please let me know if the multipluses should know not to bulk charge at all given the known SOC of 100%.

2)They system stays in absorption mode at 14.2 volts for several hours. I would expect it to drop to 13.5v immediately after 1 hour.

3) Eventually current drops to about 1A, and the voltage slowly started dropping to the 13.5v. I would expect for the cerbo and indicator lights on the multipluses to indicate float. However, they both continue to report absorption many hours later (while still holding 13.5v).

Prior to connecting the Cerbo GX, the multipluses operated exactly as configured with a 1 hour absorption and then the indicator lights reflected float when voltage started dropping towards 13.5.

I understand that absorption and float don't mean the same for Lithium batteries as they do for lead, however, it still seems the correct indicators should appear based on the correct voltage. It leaves me concerned that I don't have the configuration is correct.

Could this have anything to do with (SCS) Shared Current Sense DVCC? It's interesting that SVS is "forced on" and STS is "forced off" yet it allows me to chose on or off for SCS. So I'm not sure if I should have it on or off.

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brucevanderbilt commented · Feb 16, 2022 at 12:00 PM

Thanks @Stefanie for the clarification and confirmation that I'm seeing proper behavior of my system.

I also found your comments on the thread https://community.victronenergy.com/questions/114201/lynx-bms-gx-not-going-into-float-kinda.html.. which are very helpful.

Hopefully Victron releases a firmware update soon that indicates more clearly that the multiplus is under external control of the BMS.

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Stefanie (Victron Energy Staff) ♦♦ brucevanderbilt commented · Feb 16, 2022 at 12:22 PM

Welcome, Bruce. I too hope that it becomes external control (the MPPTs already have this feature) for the MultiPlus soon as it seems quite confusing.

I've recorded a full charge session, to make it more clear, although you now know how it works:

Charging at 'full' power' - charge current limit set in DVCC to 70A

CVL at 14.20V (coming from the BMS and communicated via Cerbo to the charge controllers MPPT and MultiPlus)

Battery voltage has reached 14.20V - 2h (as set in the BMS) 'absorption' phase started

Sync to 100% shortly after this screenshot

After exactly 2h CVL starts to drop slowly to 13.50V

MultiPlus remains in 'Absorption'

even at 13.50V - and

after the MultiPlus is switched off and on again, the charge mode is showing "bulk" for a very short moment and then resumes in "absorption" without doing any charge because battery voltage is at CVL level.

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