Alternator not charging.


  • Hi, I have just built up my REC BMS and the WS500, I have connected up the alternator and the WS500 as per the instructions and I am not getting any field coil output, hence my alternator isn\'t working. I have briefly tested the alternator by putting 12V across the field coil (the ws500 wasn\'t connected at the time), and I was getting full output of the alternator as I would expect to see so it seems like the alternator is working as it should. I have connected the network cable between the BMS and the WS500 and if I am correct I should see the green indicator light change to a yellow/orange colour and I am not seeing this. Could it be that the regulator is not receiving the data on the CANBus system from the REC BMS and this is causing it to stall/not operate?? Is there a way to test the CANBus signals from the REC?? Also is there a way to run the regulator without the CANBus to at least get the alternator running as a step in the right direction to getting this working?? Best wishes Michael  


  • Hey Mike, When I set up a system, I first install the default profile for my battery type and set my CANBus speed to 250K.  (Some people prefer 500K but I have seen some comms problems at the higher speed so I play it safe) I then bring up my WS500 in standalone mode and verify correct operation(In the event you lose comms with your BMS it will default to its moderate factory configuration) Once I have verified everything is good, only then do I connect my BMS after confirming my baud rate as per the CANF parameter is set for 250K as well.  After plugging in the CANBus it should switch from green to yellow/orange on the WS500 LED

  • Also make sure you use the correct CAN bus cable. Of you have connected the REC BMS directly to the WS500 you will ned an special CAN bus Cable. Usually the REC BMS comes with an cable made for Victron Cerbo GX.   Victron        -        WS500   CAN-H PIN7  -  CAN-H PIN1   CAN-L PIN8   -   CAN-L PIN2

  • Hi Rick Thanks for your helpful reply I have certainly not done any of the communication settings you have detailed above. Which profile would you suggest that I use to do the initial installation? I have installed the REC profile I thought that was the right thing to do, I am running 280AH EVE LiFePO4 with a REC BMS. Have I missed some installation instructions or is this procedure documented somewhere, I haven’t seen it? I will try and get to the boat in the next couple of days. Best wishes Michael

  • Quote from Trond Arvid Røsvik on August 30, 2022, 2:02 pm
    Also make sure you use the correct CAN bus cable. Of you have connected the REC BMS directly to the WS500 you will ned an special CAN bus Cable. Usually the REC BMS comes with an cable made for Victron Cerbo GX.   Victron        -        WS500   CAN-H PIN7  -  CAN-H PIN1   CAN-L PIN8   -   CAN-L PIN2
    Hi Trond Arvid Rosvik Thanks for your reply, I am using the CAN-Bus cable that was supplied by REC and as far as I know the REC is operating as it should, but I haven’t set the communication baud rate so suspect this could the issue. To be honest I am not really sure where I set this?? But I will try and get do to the boat again in the next couple of days and try and work it out. Thanks again for your help. Best wishes Michael

  • Its all in the manual. https://www.rec-bms.com/wp-content/uploads/2022/02/UserManual_ABMS_Victron_Wakespeed.pdf The command to set the canbus speed to 250kbps is: CANF 250 After that, you have to power cycle the BMS.   REC and Wakespeed can be complicated to set up for the first time. Its not plug`n play.. have to read up on it.   Again, the CAN bus cable that came with the BMS is probably not meant to connect directly to the WS500 unless you ordered it specialy for that.  

  • Quote from Trond Arvid Røsvik on August 30, 2022, 2:35 pm
    Its all in the manual. https://www.rec-bms.com/wp-content/uploads/2022/02/UserManual_ABMS_Victron_Wakespeed.pdf The command to set the canbus speed to 250kbps is: CANF 250 After that, you have to power cycle the BMS.   REC and Wakespeed can be complicated to set up for the first time. Its not plug`n play.. have to read up on it.   Again, the CAN bus cable that came with the BMS is probably not meant to connect directly to the WS500 unless you ordered it specialy for that.  
    Hi Trond Arvid Rosvik Thanks for this I will certainly read up on it, and print the instructions out. My REC BMS has been back to the supplier twice already because the unit wasn’t doing what it should have…… When it was sent back the last time it was specified that I was going to use it with a Wakespeed regulator and was supposed to be set up for this, but it appears this hasn’t been done as the LED is not changing colour. It’s a shame that no one has put a video up showing how to set it up to get both units to play nicely as you say it’s not really that plug & play. Thanks again for your help Best wishes Michael

  • Michael,   Trond makes a good point here.  Wakespeed uses a different pinout than most devices such REC and Victron so you need to be careful as if you were to connect a standard Ethernet cable, you will put high voltage on the comms pins of your REC BMS causing it to reset and possible be damaged.  We sell the correct REC to WS500 cable here. https://www.offgridsoftwaresolutions.com/product/rec-ws500-canbus-cable/

  • Quote from Rick-admin on August 30, 2022, 10:19 pm
    Michael,   Trond makes a good point here.  Wakespeed uses a different pinout than most devices such REC and Victron so you need to be careful as if you were to connect a standard Ethernet cable, you will put high voltage on the comms pins of your REC BMS causing it to reset and possible be damaged.  We sell the correct REC to WS500 cable here. https://www.offgridsoftwaresolutions.com/product/rec-ws500-canbus-cable/
    Hi Rick OK, thanks for this, reading Trond’s initial post again, I am using the cable that came with the REC BMS, and from what he and you are saying this is the cable for the Victron units only? I want to also connect the BMS to a Victron unit eventually, so can I make the pin out change between the Victron layout and the Wakespeed with a bespoke network cable, I have the tools to make a bespoke network cable. I have connected it up with the wrong cable as I didn’t know differently, I have to hope that it hasn’t damaged the REC BMS, is there any way of testing the REC BMS CAN-Bus output or am I best to make up the network cable and test it? I went down this BMS and regulator route as it seemed to be the sensible route with the BMS driving the regulator and ultimately the alternator, I still think it’s the right way forward to get the the system to work as it should. Thanks again for your help. Best wishes Michael

  • Yes, probably your cable is meant for connection to Victron, but we dont know that. You can see that by looking at the RJ45 connector. Is there cables on PIN 7 and 8? Or is there cables on PIN 1 and 2?   You can simply cut of the cinnector and crimp on an new RJ45. Then you need to move:   CAN-H PIN7  -  CAN-H PIN1 CAN-L PIN8   -   CAN-L PIN2

  • Quote from Trond Arvid Røsvik on September 2, 2022, 1:06 am
    Yes, probably your cable is meant for connection to Victron, but we dont know that. You can see that by looking at the RJ45 connector. Is there cables on PIN 7 and 8? Or is there cables on PIN 1 and 2?   You can simply cut of the cinnector and crimp on an new RJ45. Then you need to move:   CAN-H PIN7  -  CAN-H PIN1 CAN-L PIN8   -   CAN-L PIN2
    Trond Arvid Røsvik Thank you, Thank you, you were spot on the money and  correct, you have saved some more grey hair........... I want to add a Victron inverter/charger in due course so rather than cut the plug off as you suggested I have made a crossover network cable, thank you for pointing out the different pin outs between the units, you are a star...... Thank you Rick-admin for your help too, it seems that the CAN-Bus is working OK, is there any way of testing this or by the fact the LED has changed from green to orange it is working as it should??? I want to add a Victron Multi2 inverter/charger this winter as my existing big charger has died, so I really wanted to keep the Victron pinout. I assume I have to add a Venus GX or Cerbo GX  to get the REC BMS to talk to the Victron unit via the CAN-Bus??? Thanks again both for your help. Rick please move this post if its in the wrong category. Best wishes to all Michael P.S. just need to extend the alternator temperature sensor now and get the engine speed into the regulator too.........

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