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brucevanderbilt asked

Lynx Smart BMS - VE.Configure Settings

I've installed a pair of multiplus 12/3000/120 (in parallel), with Lynx Smart BMS (500a), 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.

I'm not finding any online information that reflects the correct VE.Configure settings for my system that reflects the latest firmware in regard to charger Tab in VE.Configure. Existing documentation indicates that I need to setup an assistant for my Lynx BMS. However, the new firmware indicates that has been deprecated in favor of the settings available on the Charger tab.

The logical settings in VE Configure, under the Charger tab, is to choose the battery type "Victron Smart Lithium Batteries, i.c.w. with VE.Bus BMS.”.

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This appears to give the what would seem to be the correct settings. This checks the boxes for "Lithium Batteries" and "Configured VE.Bus BMS"and the rest of the settings on this page conform to the batteries' recommendations (e.g. absorption voltage=14.2v).

However, with the “Configured for VE.Bus BMS” box checked, the Multiplus kicks off a low voltage alarm and resets itself every 20 seconds, despite voltage at the Multiplus of 13.1V. When I go back in to settings, and I uncheck the "Configured VE.Bus BMS" box, then everything works great and the system seems to be fully operational including balancing the new batteries.

I'm concerned that my Multiplus is not communicating properly with the BMS because when testing the system by disconnecting one of the BMS cables from a battery, the Multipluses continue to charge while the BMS is giving error lights and making a clicking sound.

It seems I should be able to use the “Configured for VE.Bus BMS” setting without getting the low voltage alarm. Any recommendations as to what I have wrong?

Lithium BatteryBMSmultiplus ve.bus
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Stefanie (Victron Energy Staff) avatar image
Stefanie (Victron Energy Staff) answered ·

Hi @brucevanderbilt,

no VE.Bus BMS assistant required with the Lynx Smart BMS.

You choose Lithium Iron Phosphate (LiFePo4) Batterie and make sure it has the correct settings for Absorption and Float Voltage (14.20V and 13.50V). I think it's even enough to just choose Lithium Batteries. That's what I did on my system (4 batteries). Lynx Smart BMS in control of Cerbo GX will care about voltages etc.

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Once set and everything is up and running, do the test again and unplug one of the BMS cables from the Lynx Smart BMS.


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brucevanderbilt avatar image brucevanderbilt commented ·
Thank you Stefanie,

It's a bit confusing as to why there is are actual settings for Victron Lithium batteries and Lynx BMS available on the Charger Tab, but not to use them?

Do you know the exact behavior I should expect to see when I unplug a BMS cable from a battery? I expect to see the Multiplus stop charging, however, it continues to charge. I do get an error light on the BMS as well as a clicking sound from the Cerbo GX though. So it feels as though the BMS is not communicating properly with the Multiplus.

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Stefanie (Victron Energy Staff) avatar image Stefanie (Victron Energy Staff) ♦♦ brucevanderbilt commented ·

The clicking sound you hear is probably coming from the Lynx Smart BMS contactor which opens and closes as a result of the misconfiguration.

May I ask what "Existing documentation" you are referring to where it says to set Victron Smart Lithium i.c.w. VE.Bus BMS for your Lynx Smart BMS?

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brucevanderbilt avatar image brucevanderbilt Stefanie (Victron Energy Staff) ♦♦ commented ·

Thank you for the clarification on the check box for "configured for VE.bus BMS." It is confusing.

The documentation I referred to is a combination of the Victron Document titled "Manual-A-Guide-to-VEConfigure-EN.pdf", Peter Kennedy's blog on Victron Lithium Setup, and various threads. None show the option available for "Victron Smart Lithium i.c.w. VE.Bus BMS" under Battery types. Whereas I do with my setup, which had me thinking that since I have the absolute latest firmware, that those documents are dated. And it seemed logical that I do have Victron Smart Batteries and it would be a good choice vs. the Standard Lithium LifePo4 option.

I ran the BMS test again, and it worked, I just gave it a little more time. The behavior was as follows:

1) Immediate error light on BMS with clicking sound. Note, the clicking sound is faint and rhythmic like a clock. Not the sound of the contactors opening.

2) After about 15 seconds, the contactor opened, the multiplus stopped charging, and a low voltage error on the cerbo appeared.

I previously did not wait long enough when running the test before plugging the BMS cable back in. I very much appreciate the help!


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Stefanie (Victron Energy Staff) avatar image Stefanie (Victron Energy Staff) ♦♦ brucevanderbilt commented ·

VE.Bus BMS is not Lynx Smart BMS. Please don't mix them up. But I understand the confusion.

When you unplug the BMS cable, the MultiPlus should stop charging immediately and probably will issue a low voltage battery alarm. You can ignore that for now. And I think that the Lynx Smart BMS will open the contactor to prevent further discharging of your batteries. It's kind of simulating a problem with the batteries.

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Related Resources

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Victron VE.Bus BMS product page

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