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Viv Gauntlett asked

BMS CAN Bus Protocol and implementation


We are a battery and BMS manufacturer from Perth, Western Australia.

We currently have several products available in the market and are hoping to add Victron CAN Bus support in the next iteration of our BMS.

We are looking for information on interfacing with Victron products via the CAN-BMS protocol. Is it possible to obtain a copy of the specification for the protocol?

I noticed that @mvader (Victron Energy) mentioned the relevant documentation in the topic "What kind of protocol do you recommend to implement for BMS ?"

We currently have a working CANbus and are able to communicate some information to a CerboGX in our development environment. We would like to refine this based on Victron's recommended usage of the protocol.

Kind regards,

BMSbatteryVE.Cancommunication protocol
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Viv Gauntlett avatar image Viv Gauntlett commented ·

Just thought I would add some more information.

While we have the CAN bus working well, we are unable to charge our batteries above 57.3 V, even while the parameter screen reads "Charge Voltage Limit = 58.8V" and "Charge Current Limit = 50A"

Multi's have been set to float / absorbtion voltage of 58.8V and our BMS is asking for a charge to 58.8V.

Do you have any ideas what could be limiting our max charge voltage?

I am unsure whether the CerboGX / Multi-II-5000's are overriding our requested charge voltafe, or whether we have made a mistake in our CANbus implementation.


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masi avatar image masi Viv Gauntlett commented ·

I have the similar issue with an Elerix battery, it seems the ESS has some hidded parameters that overrides whatever I seted up. Unfortunately technical support of Victron is close to zero. No answers from distributors or Victron technical staff. That's it.

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David avatar image David commented ·
I’d be interested to know more about your product?! I’m in NSW.
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1 Answer
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sgrigor1 answered ·

I think ESS overwrites the charge voltages according to battery detected. I was able to switch from Pylontech to Ld Resu and the charge value was changed from 52. 4V to 57.4V. It seems that those values are hardcoded by ESS. I'd like to know what kind of CAN frames should I send to enable BMZ ESS battery that have charge voltage of 61.5V

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Just use a different name that is not seen as a different battery, the system will than only use the parameters sent by the battery.
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Related Resources

Victron VE.Bus BMS product page

Victron 3rd party BMS compatibility page

Additional resources still need to be added for this topic