Lynx Ion BMS and Skylla-I low voltage alarm warning.

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jonathant4 asked Nov 17, '21

Lynx Ion BMS and Skylla-I low voltage alarm warning.

Hello,

Have run into an issue when using a Skylla I with a Lynx Ion BMS system. The issue is once the Victron Lithium’s are fully charged it opens the allow charge solenoid, this causes the Skylla-I to trigger a low voltage alarm on the colour gx as there is no longer any voltage on the charge bus as it’s not connected to the batteries anymore. It seems as if the Skylla-I hasn’t been designed to work with the Lynx Ion BMS however this is a bigger victron system and we don’t want alarms coming up when there is nothing wrong. Am hoping someone has run into this issue before or knows of a solution or might even have the exact same setup and don’t have this alarm. Any help or info on what others have done is much appreciated.

BMS CCGX Color Control Skylla

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Answer 1 · 2021-11-17T17:37:06Z

Mike Dorsett answered · Nov 17, 2021 at 05:37 PM

Having the Charge relay open is NOT a 'nothing wrong' situation - this should be regarded as an error.

You need to reduce the charge voltage from the Skylla so as the battery voltage does not rise to the point where the BMS does not accept charge any more. Charge should be limited by the set points in the charger, not the cut off voltage of the BMS. This will also prevent the 'low voltage' alarm.

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Answer 2 · 2024-07-08T18:29:21Z

bobcat answered · Jul 08 at 06:29 PM

With their flat charge voltage curves, using a voltage setpoint strategy with LFP cells will likely lead to overcharging but okay for lead acid.

I suspect the low voltage alarm you get is not when charging completes but rather when charging is enabled. Little difference but still. I think voltage is sensed before the batteries are connected so the alarm is triggered. My guess is you get an arm recovery message seconds later?

Maybe you should not use the Lynx relay output and instead rely on the VE-CAN-bus? In the manual, it says, "A Lynx Ion can be connected to the Skylla-i charger directly via the VE.CAN-bus, the “allow-to-charge” condition will be communicated via the VE.CAN-bus automatically, no separate wiring is required".

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