question

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martin-fi asked

Lynx Smart BMS 500 - Discharge Floor - Hibernation Mode - self adjustment

Hello Victron Community,


We have the Lynx Smart BMS connected to one 12,8V / 200Ah Lithium battery. I think usually the battery capacity used with the Lynx Smart BMS 500 is bigger. Therefore the capacity reserve after going into hibernation mode is also bigger.

In our case the Lynx Smart BMS discharges the battery down to 8,5V before it powers completely off. Power consumption in hibernate mode 12V system is 0.25mA - 0.35mA .


MY QUESTION:

Will it be possible to self adjust the discharge floor for smaller battery capacities & switching Bluetooth off to lower the Power consumption in hibernate mode?


The best option would be that the user could self adjust the discharge floor parameter higher than 15% himself. For safety reasons the minimum discharge floor parameter can be 15%.



Relavant passages from the manual:



"Discharge floor The “Discharge floor” parameter is used in the time remaining calculation. The battery monitor calculates the time it takes until the set “discharge floor” has been reached. It is also used to set the state of charge alarm defaults. The discharge floor parameter is fixed at 15%."



"9.3.7. System in sleep or hibernate mode This is indicated by the status LED off and the Bluetooth LED flashing every 3 seconds. The Lynx Smart BMS goes into sleep or hibernation mode once the battery or a battery cell has been deeply discharged. The Lynx Smart BMS will conserve as much power as possible, to not discharge the battery much further. Bluetooth is still active, but other non-essential circuits are turned off, including the power to the Lynx Distributor(s). Check the voltages of the connected batteries and if they are low, charge the batteries. As soon as the Lynx Smart BMS sees a charge voltage it will automatically re-activate and close its contactor to allow for battery charging."



"Hibernation mode The Lynx Smart BMS is in hibernation mode when the Lynx Smart BMS has turned itself off because of a low battery event or when it has been turned off via the remote on/off switch. In hibernation mode, the contactor and most of the electronic circuits are turned off and the power consumption is very low (0.8mA). The status LED is off. The power to the Lynx distributor(s) is turned off. Bluetooth is still active during hibernation mode. The blue Bluetooth LED is either flashing every 3 seconds or is on, depending on whether there is an active Bluetooth connection with the VictronConnect app. The Lynx Smart BMS will come out of hibernation mode when the remote on/off switch is switched on or the batteries are charged."

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1 Answer
Stefanie avatar image
Stefanie answered ·

Hi @Martin_FI,

Unfortunately, your post got lost in the multitude of other topics. Sorry for the late reply.

I hope it's only a typo with the 8.5V?

That should/can/must not happen. Especially not with the Lynx Smart BMS. At the latest when a cell voltage of 2.80V to 3.10V (depending on the setting of your Smart Lithium) is reached, there will be a pre-alarm (audible or visible if you have wired a light/LED/speaker to the alarm relay) and then 30 seconds later (if you don't intervene and turn on a charger, for example) the BMS will open the contactor and thus switch off the loads and then going into hibernate/off mode. So we are talking about a battery voltage between 11.20V and 12.40V and not 8.50V. I would strongly recommend that you check this again.


Now to your question:

I like the idea of having the discharge floor adjustable, although I'm constantly monitoring my batteries and just looking at the SoC is a pretty good guess as to how much longer I can draw power from the battery to be on the safe side.

A larger battery (bank) naturally has a larger capacity reserve. But the 15% is always the same no matter the size of the battery.

I will forward this to Victron.


ps. Is there a reason why you mention "Hibernation" mode", Section 9.3.7 in the manual in this context?

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