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bomax182 avatar image
bomax182 asked

Wakespeed charging SmartLithium batteries at 13.50v after DVCC update

I noticed that my Wakespeed WS500 controlled alternator is only charging the Victron SmartLithium batteries at 13.50-13.52v (@100amps). This seems low to me, and I expected it to rise to 14.2v for absorption and cell balancing. But that doesn't seem to happen (at least within an hour or so of monitoring).

I have the Lynx Smart BMS controlling everything via DVCC after the latest firmware update from Wakespeed. The Wakespeed reports it's correctly in Slave Control operation as before.

Otherwise everything is working as it always has, but it seems now that the DVCC has been introduced in this firmware update, the system is limiting the alternator charging voltage to 13.50. It is as though it's limited to Float. I am almost certain it used to rise to 14.2v as expected prior to updating the Wakespeed firmware.

Is this expected/normal?

Lithium BatteryDVCCalternator
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pwfarnell answered ·

When running on the WS500s own charge algorithm every time you started the engine the alternator would go to absorption at 14.2V and then after absorption it would go to float at 13.5V. It would do this even if an absorption charge was not really required, even if the batteries were quite full.

Now the Lynx BMS controls the charge voltage and you need to understand how the Lynx BMS looks after charging and read this in the manual. To explain briefly, once the Lynx has completed absorption, it requests float voltage of 13.5V. It stays on float voltage until either 30 days have passed or the SOC falls below 70%. Therefore, the batteries only get an absorption charge when required, if the SOC is still above 70% when you start the engine it charges at 13.5V and this is high enough to keep the battery around 100% SOC.

You can see this if you go into your Venus device (Cerbo etc) or VRM and look at the CVL (charge voltage limit) value, this is what the BMS is asking the chargers to charge at.

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pwfarnell avatar image pwfarnell commented ·

@bomax182 here are the Ly x settings which control a new charge cycle


screenshot-20240706-215837-kindlephoto-1081424540.png

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pwfarnell avatar image pwfarnell commented ·

@bomax182 If you go into the Venus device menu and go to the Lynx BMS and click on this you should see the following page to show the limits the BMS is setting.

29562-bildschirmfoto-2022-02-16-um-084801.png

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bomax182 avatar image bomax182 pwfarnell commented ·

@pwfarnell Thanks for the quick and detailed replies. Everything you said makes sense. What I forgot to mention in my original post is that the SOC was only about 50% when I fired up the motor, well below the 70% charge threshold (I confirmed this is what mine is set to).


I also checked the Parameters screen per your suggestion and confirmed the CVL is set to 14.20v as I’d expect.


I just tried everything again after verifying correct settings on the Wakespeed. Now the voltage rises up to 13.62 @ 106A but doesn’t seem to want to rise above that.


Is there something that could be making it difficult for the alternator to bring the voltage to the requested 14.2v? I’m running it at a healthy RPM (2000rpm) and it’s not overheating (90°C). Field is at 100%.

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DVCC chapter in GX manual