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stevomyatt avatar image
stevomyatt asked

Lynx Smart BMS + WS500

Hi, I see the new schematic diagram showing the lynx bms and ws500 indicates that CAN comms to the ws500 is still under development. Any indication when this might be ready?

With the ATC control of the ws500, does this open before the contactor opens to avoid load dump damage to the alternator? Is this also the case when the bms is turned off by the remote contact?

Also wondering how the relay output is configured on the lynx bms and why the ATC signal is wired through the relay for the ws500?


Thanks and nice work on the new product!

BMS
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5 Answers
bathnm avatar image
bathnm answered ·

Details to support the diagrams I believe are coming. I believe you are correct in your assumption. The relay will when firmware in the Lynx BMS is updated and relay mode set within updated VictronConnect allow the relay to open seconds before the contractor on the Lynx BMS opens, thus allowing the Wakespeed to shut down before the batteries are disconnected, thus protecting against load dump.

Not aware of any timelines for CAN integration, but hope soon as I’d really like to go down that route. Note that you will need a special CAN cable as the pin outs in the Wakespeed and Victron are different….

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stevomyatt avatar image
stevomyatt answered ·

Note full CAN support has been released between Victron and Wakspeed, with the Victron wiring diagram updated accordingly. Excellent work!

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bathnm avatar image
bathnm answered ·

Yes all works great. Make sure you use the configuration on the Wakespeed site and beta firmeware

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stevomyatt avatar image
stevomyatt answered ·

Hi @Bathnm, are you able to provide any detail on the battery temp over CAN to the WS500? I have Victron smart lithiums and a Lynx BMS on CAN to a WS500.

$AST: BTemp is reporting -99

The Lynx/WS500 wiring diagram indicates a wired battery temperature sensor is not required.

I'd like the WS500 to shutdown dependent on battery temperature over CAN. Do you know if this is possible/should be working?

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bathnm avatar image bathnm commented ·

@stevomyatt Hello there. The value of -99 is because no temperature sensor has been detected. For information the same will be reported for alternator temperature if there is no sensor on that connection.

The WS500 will follow charging criteria (voltage and current) as set by the Lynx Smart BMS. The Lynx Smart BMS will know if there is a temperature issue, aka too cold, and will send the relevant CAN messages to stop charging, as it does today for the MultiPlus/Quatro and MPPTs

There is no need to wire any temperature sensors to the WS500 or receive any via CAN.

For information you will see the WS500 in status EXT Control, just like the MPPTs and MultiPlus/Quattro.

You need to make sure that the system follows the configuration as defined in the default Lynx Smart BMS configuration as published on the WS web site. This ensures that when the Lynx Smart BMS opens it contractor or signals a charge disconnect or the WS500 looses contact with the Lynx Smart BMS the WS500 actions the correct behaviour.

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stevomyatt avatar image stevomyatt bathnm commented ·
Thanks @Bathnm, that all makes sense. I'm currently testing with WS 2.5.0 and Lynx config modified for shunt = not at battery (plain shunt installed on alternator positive) and ignore sensors = 0.
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bathnm avatar image bathnm stevomyatt commented ·

@stevomyatt great that is how I have it configured. If you pull the CAN on the LynxBMS, you should see the WS500 error in the VenusOS UI and also drop charge to a get home voltage level of 13.2 for a 12v system or 26.4v on a 24v system. If you pull the charge disconnect, which is wired to the feature in, the regulator should switch off and also provide an error on the VenusOS UI.

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stevomyatt avatar image stevomyatt bathnm commented ·

@Bathnm I'm doing some more testing and seem to have run into a problem.

I can't get the local shunt current to display on VenusOS. There is a slight change between WS 2.4.3 and WS 2.5.0, I'll try to explain:

With 2.4.3, when CAN disconnected, local current shunt is displayed as both ALT and BAT current (AST;). When CAN is connected, both ALT and BAT current changes to Lynx BMS current. This current is displayed on VenusOS.

With 2.5.0, same as above, however when CAN is connected, current is not displayed on VenusOS, only dashes.

WS HW version 2 (printer USB socket)

2.4.3.png

2.5.0.png

CAN Disconnected to Connected.png

Lynx.Lithium.configFile_Local Shunt.txt

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243.png (19.5 KiB)
250.png (20.4 KiB)
can-disconnected-to-connected.png (31.4 KiB)
lynxlithiumconfigfile-local-shunt.txt (2.0 KiB)
bathnm avatar image bathnm stevomyatt commented ·

@stevomyatt Where do you have your shunt wired and configured?


If the current field and therefore power field contain -- then the system is not receiving any current readings from the WS500 for the alternator only battery values. This is likely due to one of the following reasons

  • The shunt is configured as being located at the battery and therefore the WS500 does not have any alternator current reading. Check the configuration of the shunt through the CST terminal output. If the CST line has a ShuntAtBat? Set to 1 then this will be the reason. Modify the ShuntAtBat? through the $CST configuration line and set it to 0.
  • The shunt is not connected to the WS500
  • The system has been told to ignore the shunt sensor. Check the $SVC terminal output. If the $SVC line is reporting an Ignore Sensor configuration which includes ignoring the Local Current Shunt, then this would be why. Modify the Ignore Sensor line through the $SCA configuration line.


WHY

The change in between 2.4.3 and 2.5.0. The relevant CAN messages used to have current populated in the alternator message irrespective of shunt location. This is wrong, as if the shunt is connected to the battery it is reporting battery current and not alternator current. Therefore the shunt must be at the alternator and configured as such

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stevomyatt avatar image stevomyatt bathnm commented ·

Hi @Bathnm, the alternator shunt is wired at the alternator on the positive output. Both parameters have been changed to set the shunt at batt = no and ignore sensors = 0. This can be seen in the CST and SVC lines and config attached.

When CAN is disconnected from WS500 the AST line displays alternator current for both battery and alternator current (in the attached example this is when the alternator is off so current and power = 0) but when CAN is connected, AST line displays Lynx battery current for both battery and alternator current (in attached example this is -0.6A, -31W).

I'm expecting to see AST display Lynx current for battery and shunt current for alternator (0A while alternator is off) but it seems as though the WS is always using Lynx battery current.

Does your AST line show different values for the battery and alternator current?

CAN Disconnected to Connected_1.pngCST_1.pngSCV_1.pngLynx.Lithium.configFile_Local Shunt.txt

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cst-1.png (47.3 KiB)
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lynxlithiumconfigfile-local-shunt.txt (2.0 KiB)
bathnm avatar image bathnm stevomyatt commented ·

@stevomyatt thanks for the screen shots. Strange in deed.

I see this is at idle. What are you getting when the engine is started and the alternator is actually generating. I have seen mine show -- even in initial start and prior to actually generating.

It is also possible at idle with no engine running that the AST line and CAN messages that are being broadcast are not matching. Do you have access to the Cerbo via ssh? If so we can get some CAN dumps and look at those as well.



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stevomyatt avatar image stevomyatt bathnm commented ·

@Bathnm thanks for the ideas. I'll test with alternator running and look into accessing via ssh (have not done this yet).

I wonder if its related to the delay check logic in the WS - waiting to see a bulk phase (refer attached).

WS Config Guide_Delay Check Shunt.jpg

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ws-config-guide-delay-check-shunt.jpg (226.2 KiB)
stevomyatt avatar image stevomyatt stevomyatt commented ·
@Bathnm Sorry for the delay in getting back to you. I have tested with alternator running and everything seems to be working as expected now. Agreed, there is a small delay before the alternator current comes through, presumably to ensure the shunt is functional.
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bathnm avatar image bathnm stevomyatt commented ·
@stevomyatt Yes the delay is the system detecting the shunt is correctly reading. It needs to detect an average reading of positive or negative of >5A. As soon as it has done this it starts responding.
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stevomyatt avatar image
stevomyatt answered ·

@Bathnm

Regarding the WS500 target amps. This appears to correspond to the VenusOS charge current limit (CCL) (200A in my case). In VenusOS DVCC settings, when I set Maximum Charge Current to 100A, this is not reflected in the WS500 - it remains as 200A.

It would be nice if the WS500 could be incorporated into the Victron maximum charge current logic.

Target Amps.png

Limit Charge Current.jpg

Screenshot_20220626-211952_VRM.jpg


target-amps.png (49.2 KiB)
limit-charge-current.jpg (316.9 KiB)
screenshot-20220626-211952-vrm.jpg (196.4 KiB)
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bathnm avatar image bathnm commented ·
@stevomyatt. The WS500 is taking it's charge direction from the Lynx Smart BMS (Feature introduced to the WS500 in 2.4.2 with CAN profile 16 and 17). What has been introduced in VenusOS2.90 Beta and WS500 2.5.0 Beta is the ability to monitor the WS500 from VenusOS. What you are requesting is the integration of WS500 into the Victron DVCC structure so that the WS500 takes charging targets from VenusOS, this is not targeted for these two releases.
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stevomyatt avatar image stevomyatt bathnm commented ·
@Bathnm ok, perhaps in the future if the integration progresses!
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