Bmv 712 setup for Chins 300ah question

Bobastrat

New Member
Joined
May 16, 2021
Messages
8
For the battery most specs I could find is below:
Chins 300ah LiFePO4:
Rated Capacity (0.2C): 300Ah / 3840Wh
Cycle life: 2000+ cycles at 80% discharge depth
Rated voltage: 12.8V
Charge voltage: 14.2 - 14.6V
Depth of Discharge (DoD): 100%
Standard charge current: 60A
Charging time: Approximately 6 hours
Max continuous charge current: 100A
Max continuous discharge current: 200A
Peak discharge current: 600A (Duration: less than 3 seconds)
Operating temperatures: Charge 0°C~50°C(32°F~122°F),
Discharge -20°C~60°C(-4°F~140°F), Storage -20°C~50°C(-4°F~122°F)
Impedance: ≤ 15mΩ

My question is in the Victron connect settings for the bmv712 what should the following be for best results:

Under battery settings:
charged voltage:?

discharge floor:?

Tail current:?

charge efficiency factor:?



Under relay settings:
relay mode:?

invert relay:?

min close time:?

relay off delay:?

low soc relay: ?% ?%

low voltage relay:?

high voltage relay:?


Thanks!
 

mikefitz

Solar Addict
Joined
May 28, 2020
Messages
859
You need to change the following , the default settings are OK for the rest.

Battery capacity, your actual capacity, 300
Charged voltage
, the charge voltage your chargers are set to, minus 0.1 volt, example charge voltage 14.2, BMV setting 14.1
Puekert Exponent
1.05
Charge efficiency factor 99%


The BMV syncs to 100% when the voltage is above the charge voltage and the current is below tail current and both the conditions are valid for the charge detection time.

Its possible when charging with a power source that varies in output, for example solar, the current may fall below the tail current before fully charged and give an incorrect sync to 100%, adjusting the tail current ( lower) and/or the charger detection time (longer) may help.

Its also possible to manually sync to 100% when you are sure the battery is fully charged and continue to use this method at intervals, disabling the auto sync by changing parameters to values that would never be reached, example charged voltage 15 volts.

The relay and alarm settings are totally independent of the display and calculation for battery capacity.
The relay settings only need to be set if you intend the relay outputs to control part of the system.
You can also configure alarms.
With lithium batteries for long service life operating above 15 to 20% of capacity is considered good practice. The settings for the relay and alarm could reflect this.
Useful guides,

All battery monitors will over time accumulate errors and give incorrect readings. If the battery is regularly charged to full then the auto sync using the above settings should keep things in order.

Mike
 

gwliddle

New Member
Joined
Dec 10, 2019
Messages
15
Hi guys, may I jump in with a question? I have a BMV-700 and would like to make sure I have it set correctly. The part I'm concerned about is the Low SOC relay setting. The manual says it is used to calculate remaining time. If I disable this relay function using Connect App, will the BMV-700 still calculate remaining time? Under battery settings I set Discharge Floor =20%. Will it determine time remaining from this setting if relay Low SOC is turned off?
 
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