question

John Rushworth avatar image
John Rushworth asked

Lynx Ion BMS - SOC and Consumed Ah incorrect

My system consists of:

1 x Lithium HE battery 24V / 200Ah

1 x MultiPlus C 24/2000/50 (Latest firmware 433)

1 x Lynx Ion BMS 400A (v1.14)

1 x Color Control GX (v2.23)


The system is running DVCC. In the screenshot below the SOC shows as 75%. As it's a 200Ah battery surely the consumed Ah should show as 50Ah but it shows as 37.5Ah. Conversely if the 37.5 Ah is correct then that means the battery has a capacity of 37.5 x 4 = 150Ah.

Am I missing something, any idea what is going on?

SOCDVCC
img-7986.png (440.5 KiB)
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1 Answer
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hey John, I know I owe you an answer on this one :-). And I’ve asked and know it now:


The Lynx BMS has two modes: default, and performance.


In default mode it offers limited capacity to ensure a longer battery life. Its limited to ~75% of the capacity.

In performance mode it allows 100% of capacity.

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John Rushworth avatar image John Rushworth ♦♦ commented ·

Thanks Matthijs That now makes sense, thought I was going crazy!

Your answer begs the question what is the Cycle Life @100% DoD (0,3C) and @75% DoD (0,3C), as in the datasheet we just give Cycle Life @80% DoD (0,3C) as 2000 cycles.

How does one enable performance to get the full 200Ah / 100% as that is preferable in my application, subject to cycle life answer?

A nice surprise to be able to have 5kWh of useable energy in performance mode compared to the 4kWh I assumed from the datasheet @ 80%DoD.

(Edit - I have discovered that changing between default and performance can be done with the BMS tool available in https://professional.victronenergy.com/downloads/firmware or it seems the facility will likely be available soon via the CCGX/VRM. As the cable for the tool is expensive, waiting for it via the VRM seems preferable.)

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Pat Davitt avatar image Pat Davitt John Rushworth ♦♦ commented ·

Good question. I'm interested also.

Pat

1 Like 1 ·
mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ Pat Davitt commented ·

Hey John; as you discovered yourselves, it can be done using the PC software called "Lynx Ion BMS tool"; available on Victron Professional in the downloads/firmware section.

Yes this requires a USB-CAN device; and yes they are expensive.

There are no plans that I know of to make it possible to change that in a different way in the near future. Long run for sure; yes.

We do lend those can devices to our dealers btw.

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Related Resources

Additional resources still need to be added for this topic

DVCC chapter in GX manual