WS-REC-Cerbo slave issues?


  • I have an installation with WS, REC bms and Cerbo that works quite well. But there are two challenges I cannot solve. When WS is in slave mode (REC), float mode does not work via \"feature in\" so I had to set this to \"half mode\" and define a 30% field to be able to regulate down the power (200a) dynamo. Is there any solution to this? The second challenge is that battery volts and dynamo volts are identical. When charging at 200a, I have a 0.6v drop to the battery. I assume WS senses dynamo volts from power supply (red no. 6) as this is the only wire WS has this info available. Is there a bug in the WS software under external control?


  • Hey Johnny, this is one we will have to push back to Wakespeed for a reply. Copy to Al at Wakespeed @al-thomason

  • I did bring both these issues up with AL in October 2022. Attached is an photo to illustrate.   The first issue kind of makes sense as the float voltage is defined in the BMS, And the WS500 can not foresee what this float value will be. It has to choose to ignore the CAN bus charge voltage and use its internal setting.  

  • Quote from Jonny Sollid on March 2, 2023, 11:31 am
    I have an installation with WS, REC bms and Cerbo that works quite well. But there are two challenges I cannot solve. When WS is in slave mode (REC), float mode does not work via \"feature in\" so I had to set this to \"half mode\" and define a 30% field to be able to regulate down the power (200a) dynamo. Is there any solution to this? The second challenge is that battery volts and dynamo volts are identical. When charging at 200a, I have a 0.6v drop to the battery. I assume WS senses dynamo volts from power supply (red no. 6) as this is the only wire WS has this info available. Is there a bug in the WS software under external control?
    DISCLAIMER:  Al from Wakespeed Hello. As the Ws500 is in Slave Mode, none of the WS500 Charge Profile items are in effect; so there is no \'Float Mode\' to select.  If your goal is to reduce loading on the engine for some points of operation, your approach of selecting half-power and defining a lower de-rate is a good one.  Of course, check out White Space and see if that addresses some system design aspects. As to Alt Volts vs Battery Volts (and the AST line I am assuming):  The WS500 has the ability to use Remote Instantiation via CAN for battery insight.  Mostly this is used for battery temperature and current; however, there is also the ability to use remote sensing of Battery voltage as well  -- but it requires special capability from the BMS which today is not present (Support for DC_SOURCE_STATUS_5 message specifically).  In installs where remote instrumentation of battery voltage is being used, you will see different values in the AST line. Now, the Ws500 (Gen 2 design, Type-B USB) also has a 2nd voltage sensing on the RED ALT+ wire.  We use it today to trap excessive voltage drop between the alt and the battery, as well as a 2nd sense point for load-dumps.  This also assumes the RED wire is on the alternator vs. on a common bus bar.   But that sensor is not very accurate, so at this point it is not sent out - either in the AST line, nor in any of the CAN messages.  We are looking to perhaps improve  ALT+ voltage sensing accuracy and might make a change in future firmware leases.  But for now, it is just not sufficient to be meaningful outside the gross traps noted above.        

  • Thanks Al for your well explained answers. My wish is to be able to regulate charging as needed (0-100%). I am in the process of installing two alternators of 250A each and then it is a big advantage to be able to regulate the current steplessly and not just two different effects as I have today. Is it possible to add field current adjustment (0-100%) to the Cerbo menu?

  • Hello Jhonny, Ben here. Your suggestion from field control through the Cerbo is maybe not the best approach.   But the Cerbo has already a \"max\" amp setting under DVCC which would be nice if that should function with the WS500.   As far I understand this means a update that Victron needs to do. Would be a nice upgrade if Victron is willing to make this possible.   This probably will take time.   Or use the option, \"short the alternator temp sensor\", regulator goes in half power mode.  Halfpower mode can be programmed to a certain level. But Al need to confirm or this work in mode 39(bms/can control)

  • Hi Ben I agree, being able to set max charging via DVCC is the best solution, I hope it will be integrated soon. Half power mode is what I use now to regulate power down, it works ok with WS under external control of REC, but not float as I wrote in the first message.

  • Guys, after talking with Al, he confirmed that the WS500 does not integrate with CVCC yet. From Al \"And at all times the WS500 directly takes its guidance from the BMS -- Victron has not extended DVCC to the WS500 yet\" This means that if you want your non-victron BMS to control your WS500 the WS500 will need to be connected to the BMS-CAN port,  but you will lose it on the GX50-70 so to display data you want to connect it to your chart plotter using NMEA. If you really need it on your GX50-70 then you can use an opto out on the REC BMS to disable/reduce charging with the \"Feature In\" wire of the WS500. If anyone has a better suggestion I would love to hear it! @benv  

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