question

kevin-greene avatar image
kevin-greene asked

Lynx Smart BMS Charged Voltage Setting

I wanted to understand if the Lynx Smart BMS Battery monitor settings: Charged Voltage should be set 0.2V below the Absorption or Float Voltage (so set to 14.0V or 13.3V).

I have a Victron LiFePo4 12.8V 1320Ah battery bank (4x330Ah)
Lynx Smart BMS and Distributors
Cerbo GX
Multiplus 3K 120V

Thanks,
Kevin

lynx bms
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4 Answers
mvas avatar image
mvas answered ·

Where in the Lynx Smart BMS manual does it state to set the "charged voltage" to 0.2v below float voltage?

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kevin-greene avatar image
kevin-greene answered ·

It doesn't specify which is why I'm asking. It just says default is 14.0V which happens to be 0.2V below the 14.2V Absorption Voltage recommended for Victron LiFePo4 batteries.

However, in this Victron overview: https://www.victronenergy.com/media/pg/Lynx_Shunt_VE.Can/en/battery-monitor-settings.html

Section 9.2 says: The “charged voltage” parameter should be set to 0.2V or 0.3V below the float voltage of the charger.

So the default looks a lot like 0.2V below Absorption and this other overview references Float.

The main reason I ask is my SoC has jumped to 100% from as low as 67%. Sometimes it doesn't jump and twice it has jumped when charge current was still 80A+. I know this is well above the tail current (which is set to 2.5%), but something is off and got me looking at the config.

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klim8skeptic avatar image
klim8skeptic answered ·

@Kevin Greene

Section 9.2 says: The “charged voltage” parameter should be set to 0.2V or 0.3V below the float voltage of the charger.

^ This info is wrong and has been rectified in the updated Lynx Smart BMS manual . Should be 14.0v. Is this even adjustable?

Re Soc jumping, check the "Battery bank capacity" setting is 1320Ah.

Re cell balancing (you have to get that sorted), check the "Number of batteries in parallel" setting

How many of the BMS settings are actually adjustable??

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kevin-greene avatar image
kevin-greene answered ·

Thanks. Battery Bank Capacity is 1320Ah and parallel batteries set to 4.
charged voltage is adjustable. The installer set it to 13.3V (0.2V below float). I changed it to 14.0V and will see if that helps.


Even with this change, I'm still not sure why the SoC would jump to 100% when the charge current was far greater than the tail current (using generator/chargers). Everything I read on this problem references Solar charging, which can have the cloud effect where current drops for a period of time. I didn't have that issue.

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