WS500 Not Keeping Battery Topped Off


  • I have a WS500, Balmar XT250 and 840Ah LiFePO4 battery on my sailboat. I have a REC BMS, but it is NOT configured to control the WS500. For now I want to have the WS charge independently.
    If I have to motor for a short period of time the combination works well. The alternator provides very good output as per the configuration of the regulator. 

    If I have to motor for several hours I am usually left with a bank that is not fully charged when I turn off the motor. When I motor and have the power available I will run my watermaker which is a 1HP AC motor run off the inverter. As I motor and make water the battery charges up and reaches 100% (Set to 14.2VDC). The regulator then ramps down and stops charging the battery. If the battery is topped off and I have a couple hours more motoring and am still running loads such as the watermaker, the battery drains down to 75 or 80 percent before I turn off the motor. 

    I don't have these extended motors very often, but when I do run the engine for a while I'd like to end up with the battery topped off if possible. 

    Should I adjust the "Revert Volts" to have the alternator resume charging sooner or is there another method of keeping the battery topped off while the motor is running? Or is it a bad idea to keep it topped off? 

    My normal charging is via solar when at anchor or a Multiplus if I have to run the generator. I don't normally run the propulsion engine for the sole purpose of charging batteries. 

    Revert Volts is currently set at 13.0. I think these were the defaults. 

     

    Thank you!

    Brent



  • Brent

    It sounds like your SOC is dropping because your "float" voltage is set to low (I assume your "revert" voltage is the "float" voltage)? By setting your "float" voltage at 13V the regulator is shutting down the alternator until the voltage at the battery drops to this point.

    As LiFePO4 holds its voltage well, the batteries are running the load this is why the SOC is dropping to 70-80%.

    What batteries are you running?? It would be worth asking them what the float voltage should be???

    Connecting the BMS will help with this as the BMS will "drive" the regulator and it will maintain the higher SOC.

    If it was me I would try a "float" voltage of 13.3v-13.4v and see how that goes...... you will find that the SOC will drop off once the batteries have been fully charged. But 70-80% is far too much.......


  • Brent 

    One thing that caught me connecting the REC to the Wakespeed is the data cable is not a straight through cable and so you need to make sure you get the pins correct there are only two used on both ends, but they are not the same.

    Good luck 


  • @Brent (Disclaimer:  Al of Wakespeed).

    As suggested by Michael, it sounds like the float voltage needs to be adjusted.  But am a bit more concerned by: 

        "I have a REC BMS, but it is NOT configured to control the WS500. For now I want to have the WS charge independently. "

    What are you using to allow the REC BMS to inform the WS500 of a pending charge bus disconnect?  Do you have some type of Wiggle-wire installed, just checking to make sure this important safety capability is somewhere if not via the CAN!

     


  • @Michael Thanks. I am going to raise the float voltage to see if that resolvese the issue. the 13.0 value was from the default LiFePO4 profile. 


  • @Al Thanks Al. I have the REC BMS but the regulator is temporarily disconnected to establish a configuration that would work without the BMS. The regulator will be reconnected to the CANBUS shortly. I am assuming the WS500 would use the configuration I establish if it is not able to communicate with the BMS. Is that a bad assumption? 

     


  • @Brent

    The idea of the BMS is to control the regulator, and will override your settings, as Al is pointing out that one of the points of CAN bus communications is if the cells are getting out of balance and a shutdown is pending the BMS will stop the charging and allow things to settle down (balance for example), well that is how I understand the system works.

    This willlprotect your alternator and electronics..... I wouldn't worry too much about the Wakespeed settings, use the default settings and connect the CAN bus to control it all......

    Think about it the Wakespeed doesn't know of any of the cell voltages where the BMS does and needs to be the control and protection all built into one..... it's a great system......

     


  • @Michael Thanks Michael. I am a little gunshy due to probems with the system over the last several months. I am regaining confidence in it. I had alternator issues that nobody was able to diagnose (OPE, REC, wakespeed and Balmer were helping). I spent a while using the alternator's built-in regulator. I also had a REC BMS fail. It turned out the cause of lots of frustration was a broken connection on the regulator ground ring terminal. The system is working well now, but I was reluctant to give control back to skynet. This morning I turned the DVCC back on and the alternator was working well in slave mode. I'll see how it goes next week when I sail to my next destination as I will have to motor for a couple hours. 

    Thanks for your comments. 


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