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REC Active BMS Not Ramping Down Near Top

  • J

    Another challenge I'm dealing with at the moment is the BMS not seeming to slow down the charging rate of the Victron Multiplus 3000 the battery gets toward full. This seems to result in the high voltage sensor going off and tripping the charge relay which in turn sends an error message to me via the Cerbo GX. I got these consistently this morning as the battery reached full.

    I'm assuming this is a settings issue. I'm surprised as this has only happened a couple of times over the last 18 months, and I haven't changed settings since initial setup.

    Here's a look at the BMS settings:

     

    Here's a look at the Volts vs. Current Logging for the Past 2 Days. (Please keep in mind, I had a failure of my alternator charging my batteries over a 5 day trip resulting in a low voltage cutout of my system. I failed to realized the alternator wasn't charging over these days, as its worked flawlessly for a long time and I got lazy about continuing to check. I ended up limping to a marina and charging up to 50% before continuing on home. During the 5 hours home there was a brief period where the XT250 alternator worked after fiddling with the wiring, however it stopped workin about 30 minutes later as shown by the major current spike. The other charging activity came from the Victron Multiplus)

    State of Charge... finally here's a state of charge graph for the past 2 days:

     

    I imagine there's a setting which help the BMS direct the Multiplus to slow and stop charging prior to hitting the voltage limit. Can you help me determine what this is and how I can improve it?

     

     

     

     

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  • B

    Only a short answer, no more time at the moment.    Having high voltage alarms after 18 months, I see that more times.  Before the cells where nice in balance and there will be no alarm.  Maybe cells are out off balance, and it gets important to have all settings correct.   Check manual or your GX settings under dvcc are made correctly. post dvcc settings here.  dvcc settings are controlling the multi.

     

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  • R

    Not sure what firmware you are running but version 2.9 has added some enhanced top voltage control.

    It starts on page 24 of the manual and you can find the update and manual here:    https://rec-bms-na.com/product-manuals/#7-8-wpfd-rec-active-bms

     

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  • B

    In VRM, you can also add a widget that show CCL and CVL, can you post them here, from the same time line as above screenshots, VRM?

     

    Also post the widget from VRM, cell minV and cell maxV.  Same timeline as above widgets.

    With this info I can see more about your issues.

     

    The new function Rick discribe is usefull, but with the older firmware the Multi is controlled also to limit the charge.

    Or this works correctly  we can see in the widget I ask for.

     

    Probably dvcc is not switch on in the GX, this means the Cerbo received de CCL and CVL commands but don't send this info to the Multi.

     

    If the Multi is not controlled, this will gives the High voltage disconnects.

     

    If all chargers are under control from Cerbo, the charge relay will never/not open. ( In normall conditions the charge relay  NEVER opens ONLY if there is any device in malfunction, or installation , design faults)

     

    Are there any other chargers in the system next to the ws500 and Multi?

    In your other post logfiles I have seen, that the WS500 is correctly controlled by the BMS. The WS500 is directly controlled by bms-CAN, independent from GX settings.

    Your charge settings are a little high, but that is maybe a personally choice.

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  • J

    Thanks for the replies.  I was able to do some of this via the VRM remote panel.

     

    DVCC: First, here's the DVCC settings:

    When I first connected and reviewed these settings the 'Controlling BMS' was set to 'Automatic'. I changed this to 'REC BMS battery'. Otherwise all other settings are unchanged.

    Also thought I would share the Battery Monitor status:

     

    CCL & CVL Graphs:

    Cells - Max & Min Graphs

     

    Let me know what you think.

     

    Also with regard to battery settings... I'm open to suggestions on settings which you might find would work better for the system. I'm using 12 280ah EVE Cells in a 4s3p configuration. 

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  • B

    Under dvcc, limit charge current, and limit voltage need to be on.  Make a setting, just higher as the BMS "goal"(CVL CCL).  The GX will take the lowest from, manual setting, or from BMS.

    When I write this, I start thinking, IF this setting is off, like Jamie has, does that mean the function is disable, OR will the chargers still follow the BMS CCL/CCV.

    Maybe someone else can answer this? Is it really needed to switch this ON?

    I always have these 2 settings ON, seams to work correctly.

    Probably this is visible when I study the VRM in detail. (Request for viewing your VRM, see in your personal messages)

     

     

    Settings is personally, but you can use if you like.


    balance END V     3,52
    balance START V   3,45
    MAX allowed cell V difference 0,25
    END of Charging V  3,52
    END off charging V Hys 0,17
    MAX allowed cell V  3,65
    MAX allowed cell V Hys 0,25
    MIN allowed cell V  2,8
    MIN allowed cell V Hys 0,1
    MIN cell V discharge (inverter through CAN) 2,9
    Charge float voltage Coefficient   1
    SOCH end off charge hystory(in%) 5


    This setting gives a ""float"" from 13.4V

    Restart to bulk if SOC is below 95% AND voltage below 13.36V.


    Check or "Charge Float Voltage Coefficient" is set correctly.
    Only possible with the WIFI, not with the PC software.

     

    I notice that the Victron Multi, is in a few causes not accurated with the output voltage level.
    (Victron refuse to look at it, they dont take me serious if I send my complains)
    If charge voltage and Cutoff voltage are to close, and the Victron put out a little higher voltage, a charge bus can switch off. 

     

    A charge bus if all devices are undercontrol form BMS-CAN, or by the GX, the charge bus should NEVER switch off.  Only when a device fails, OR like in one off my experiences, that the Victron Multi is not acuurate enough!!

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  • J

    Thank you. I updated the two settings from the remote panel and will update BMS when I get back to the boat.

     

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  • B

    @Jamie limit amps suggest to make 200amps.

     

    Looking in more detail to your VRM post from above, I see something strange.

    At 5septeber around 23:00h, I see voltage rising, but no charging amps?

    This is strange. How voltage can rise when battery is discharged?

    From my view this looks like that there is another charger, connected on the wrong side off the shunt.

     

     

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  • J

    @Ben Thanks for the advice here. 

    Voltage Spike: I don't have an explanation for the voltage spike you mentioned. The only charging devices on the boat are the Multiplus and the alternator, and two DC-DC chargers which maintain the starter & windlass/thruster batteries... though I don't think those could be the source of the voltage you mentioned. Based on the timing, I wasn't on the boat so I'm not sure of the circumstances. Though looking at the State of Charge graph, it looks like this is right around the time when the battery hit 100%.

    Settings: thanks for the settings. I'm given them a try. Though I seem to be missing one from your list (highlighted) and wanted to confirm the ones connected by the blue line are the same.

    I also set the DVCC current limit to 200 AMPS as mentioned in another post.

     

    I'm hoping this resolves the issue so I can avoid the continual high/low voltage alarms when reaching max charge.

     

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  • J

    Just because we're diving deep here I though I'd share the Multiplus settings to see if you have any concerns or suggestions:

     

     

    I would imagine the BMS would override these settings if and when it needs to, but I want to be sure there isn't a conflict contributing to the over-voltage problem.

     

     

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  • B

    @Jamie on the mainscreen GX, you need to see external control at the multi icon.

     

    Checking your VRM, there is charge current, when the cell voltage get higher. (On your posted VRM widget, this was not visible.  This means there is no stranger charger, as I mentioned before.)

    But interrupted charge, see screenshots below.  This is strange.  Checking Futher I see that the Multi shows strange voltage.

     

    This probably cause the problem from interrupted charge.  Check the voltage sense wire from the Multi.

    The problem has nothing to do with the REC, CVL is unchanged, Multi should charge stable.

     

    No where I see a higher voltage as 3.65V that indicates a high voltage trip!!

    This means the REC didn't switch off the charge relay.

    Although the Multi has monitor a high voltage!! The REC BMS NOT.  This is strange. Suggested to check all multi DC cables and fuses.

    For better trouble shooting, you need to give a drawing from your system, you have seperated load charge bus, or only one main relay?

     

     

     

     

     

     

     

     

     

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  • B

    @Ben

    Another strange event.

    System is in float 13.9( your old settings)

    See CVL.

     

     

    CVL stays constant 13.9.

    Then Multi start giving fluctuating voltages.

     

    All related to Multi, nothing strange at REC BMS side.

     

     

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  • J

    Thanks for diving deep into this. Those events are around a short evening sail I took with friends. Looks like they coindcided with starting engine, sailing, starting again, etc.

    Hopefully this is less of an issue with the new Cerbo/Multiplus settings.

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  • B

    Hello Jamie,

    New settings is better for batteries I think, not many manufacturers ask for a continuous float voltage from 13.9V.

    But your Multi is over shooting the "goal" voltage CVL, that the REC send to the Multi, continuous.

    In screenshot below, CVL is 13.9V continuous, but multi is not that stable in voltage!!!

    There most be a reason for this.

    With new settings would this change?  Has nothing todo with each other.   

     

    I suggest to check or there is a newer firmware for the unit.

     

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  • J

    Thanks again Ben. It does look like my Multiplus is out of date on firmware. I'm presently running edition 490, and it looks like that is a couple of years old. However, I have to wait until I get back onto the boat to be able to update this. I will do that and get back with you.

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  • J

    Thanks agian for the help Ben. I updated the settings per your instructions and they seemed to work better see WS500 thread for logs.

    Though, I should note I didn't see an SOCH End of Charge Historesis setting in my options via the WiFi connection. Here are the settings via the REC BMS Wifi Panel:

     

    I believe I have the latest firmware for the BMS and the Wifi so I should be seeing everything you are seeing. Let me know if I'm not.

     

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  • B

    @Jamie some settings are not on the main settings page in the WIFI.

    They are not often changed.  

    This settings you can do with, manual programming, under settings tab.

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  • J

    Worked with the manual communication tool of the WiFi portal. Here's what it reported when I did the SOCH? query: "5.00000e-2"

    I'm a business guy, not a scientist so I assume this translates to 0.05 per this handy translator.

    The setting you specified was: "SOCH end off charge hystory(in%) 5".  Since you say "in%" then I believe this means 0.05.

    This is appears to be the same as it is currently set, though just for fun I sent instructions "SOCH 0.050" to the system, and then queried to confirm and got back "5.00000e-2". So I think all is correct here.

    Let me know if I misunderstood. As always, thanks for your help!

     

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  • B

    You have the correct understanding.

    If you like 5% hysteresis, (restart at 95% SOC) you program 0.05.

    The standard, out off the box setting is 5%.

    You are right, if I share settings, it is better to mention 0.05 instead off 5, I have change it in my documentation. (good catch)

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