question

dunno avatar image
dunno asked

ESS with 2 wire BMS

Hi,

I got a Multiplus 24/3000, Venus GX and 2x MPPT 100/30 Solar chargers running togehter in an ESS System. I want to change from AGm to LiFepo4. The BMS iwant to use for the LiFePoS has a LOW-Voltage Protection Line and an OverVoltageProtection Line which i want to connect to the multiplus like it is described in https://www.victronenergy.com/upload/documents/Manual-Connecting-other-lithium-battery-systems-to-Multis-and-Quattros-EN.pdf

and setup the ESS assistant with two Signal BMS. The pdf above is meant for the Multiplus connected to shore, but does it work for Home ESS System too?


When there is no OVP or LVP fault, the AUX input and TempSense Input will be short circuited.

If there is a OVP or LVP fault, the Input pins of Temp Sense and Aux are NOT short circuited


Question:

1) Does the ESS System (Venus GX) stop the two Solar Chargers when there is an OverVoltage Signal from the BMS like described above?

2) Does the Multiplus stop inverting when there is a low voltage signal?


Kind regards,

Georg

ESSBMS
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

3 Answers
Paul B avatar image
Paul B answered ·

I would think that the answers to your question are YES


However I would ALWAY do a manual test of these features and observe that they do work, just for your own piece of mind. ie wiring issues assistant issues etc etc

Myself I us the VE-BMS unit and this works fine for myself

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

dunno avatar image
dunno answered ·

Hi,

thank you,

In the meantime I made a manual test test and short-circuited the 2 Aux1 pins and the two Aux2 pins after setting up the 2-wire BMS in the ESS assistant. Like you said, the answer to both questions is yes

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

dunno avatar image
dunno answered ·

Hello,

I did some further tests, and there is one problem with the OverVoltage logic in the multiplus. I set the Multi to "disable charger" when there is an OVP info on the aux input as described above.

The Problem. ESS isnot only disabling the charging, but also inverting. In the Venus GX one can see, that the Multiplus is in Passthru mode. Is there any poissibility to keep it inverting?

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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