question

markau avatar image

Lynx Ion 1000 A BMS Aux Power Output + SOC

Our system configuration: Lynx Ion BMS 1000A + 2x LiHE 100 Ah batteries + Venus GX + Multiplus 2

Question 1 - When have powered the Venus GX from pin A1 & A6. At what battery voltage & SOC will the BMS stop sinking power from the battery? We are concerned that the batteries may run 100% flat.

Can you further explain 1.3.2 Storage instructions of a complete system (Lithium-ion batteries with BMS) of the manual?

Question 2 - How do you change the minimum SOC from 30 % to a lower number. Is there any issue running the batteries to 5% for example? When running the unit we expect the Multiplus 2 to cut out on low voltage, but the unit allow to discharge prevented any further discharge from the batteries at 30% SOC.

Question 3 - How do you program B5&6? Is there a list of CAN instructions

BMS
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
Pat Davitt avatar image
Pat Davitt answered ·

You don't say if this is a 24V or 48V system, so I am assuming 24V.
Since you did not mention it, I also assume you are not running in ESS mode.

Question 1: Best I can tell, the BMS and the Aux output remain active after an automatic switch to standby mode by the BMS due to low voltage. (SOC is not part of the equation.) However, if you put the BMS in standby mode by pressing the On/Off switch to manually throw the safety disconnect, then the Aux output is turned off, but the BMS remains active and draws 75mW for a 24V system.

Took me a few reads of the storage instructions to understand it, but I think I finally got it. If you have a full (100% SOC) battery and manually switch the BMS to standby mode, the battery will last about 2570 days. If however, you let the battery run down to the voltage where the BMS automatically goes into standby mode, then you have approximately 128 days before the battery is damaged. Even if you disconnect the batteries from the BMS there is still a small self discharge of approximately 2Wh.


The bottom line is that at some point the user has to take action to charge the batteries to prevent damage.

Question 2: Not sure where you are getting the 30% SOC from. I have a system similar to yours and have activated DVCC (Distributed Voltage and Current Control) on the GX. This removes any charge settings from the Multiplus/Quattro and the Victron Solar Charge Controller, if you have one. The Lynx Ion BMS then directly controls the charging sources. Allow to Charge and Allow to Discharge wiring is NOT required since the control is through the VE.Bus and VE.Direct communication channels. Read section 3 of the CCGX manual.

Question 3: To setup the Lynx Ion BMS relay you must get a CAN to USB interface from Victron. This will allow your PC to talk to the BMS. Then download the "Lynx Ion BMS Tool Version 2.14 from the Victron Professional web site. You can then use the tool to program the BMS relay for a number of different conditions. Since the CANUSB interface is fairly expensive $350.00 USD and you can really screw up your system if you misuse the tool, I recommended you find a Victron Installer that has one and let him do the programming.

Hopefully a Victron staff member will join this conversation to confirm my statements above.

Regards,
Pat

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

markau avatar image
markau answered ·

Hi Pat,

Thank you for your answer. We are running a 48 V system without solar.

Please see link to my other question. This states allow to charge / discharge is required.

Our application is unique and we need to remove user error of flattening the batteries, hence we have asked the question what happens if you sink current current from the BMS running the venus GX until flat.

In our application can you discuss the benefits of using DVCC and ESS.

Thanks

Mark

2 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Mark,

I'm on phone at present, will answer when I get back to my computer. However, the use of DVCC overrides the requirement to wire the allow to charge and allow to discharge circuits.

Pat

Mark,

It is impossible to completely bullet proof any system so the batteries cannot be damaged by neglect. It doesn't matter if the batteries are lithium, lead flooded cell, or AGM. The Venus GX only draws about 60mA so it should not be a problem.

Since you have a Lynx Ion BMS 1000, this is the best BMS for use with DVCC. Read Section 3 of the CCGX manual.

Pat

markau avatar image
markau answered ·

Hi Pat,

Thanks for your assistance. in principle, with the DVCC function, is this same on the Venus GX as the CCGX?

Mark

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Yes. Both devices use the same operating system.

Pat