Victron SOC problem

I just upgraded my entire system to Victron and am using a pi3 with Venus OS connected to VRM. All seems to work well on the monitoring but my shunt doesn't seem like its accurately working.

I've included a screen capture of both my battery BMS showing the SOC and also the Victron dashboard. It seems that the Victron SOC always jumps to 100% very quickly even before the battery is actually all charged.

Multipass II 24v/3000w
MPPT 150/85
BMV-712

What are your settings for the shunt? Sounds like your charged voltage may be too low.

Shut settings are key for tracking SOC, the SCC setting are also key in determining what the shunt considers full.

JeromeS13 said:

What are your settings for the shunt? Sounds like your charged voltage may be too low.

Click to expand...

I went through VictronConnect and found these for the shunt settings. Are these also attached to the MPPT and inverter settings?

740GLE said:

Shut settings are key for tracking SOC, the SCC setting are also key in determining what the shunt considers full.

Click to expand...

Any tips on configuration?

On a Smartnetwork (just Bluetooth) the SCC charging settings adjust the shunt charged values. Not sure if the same is for a Cerbo system.

As far as your charged voltage, 26.4, that’s only 3.3v/cell.

Typically 27.2 is more accepted as fully charge at 3.4v/cell.

Doesn’t sound like muck but it’s a wold of difference.

Simonbr said:

Any tips on configuration?

Click to expand...

Currently have the Victron BMV-712 battery monitor shunt in a (510ah measured) 24 volt LFP system with the Raspberry Pi 3 Venus OS VRM. Don't have any other Victron equipment. The battery bank is charged to 28.5 volts with the solar charge controller or Samlex EVO 2224 Inverter/Charger.

Really like the Venus OS. Able to look at the BMV-712 status, output and make settings from any place. Works on my PC, iPhone & iPad.

Battery Settings used:
Battey capacity 510AH
Charged voltage 28.3V
Discharge floor 0%
Tail current 4.50%
Charged detection time 2m
Peukert exponent 1.00
Charge efficiency factor 100%
Current threshold 0.01A
Time-to-go averaging period 3m

Some say the Peukert exponent & Charge efficiency settings should be slightly different, but these settings work the best so far for my system.

Here are the settings Battle Born Batteries recommends for a 12 volt LFP battery system. Don't have Battle Born, but a good example.

• Battery Capacity: Enter the total Ah of your battery bank. (i.e. 400Ah for 4 – 12V 100Ah Batteries wired in parallel.)
• Charged Voltage: Set to 14.4V, but make sure it is about 0.1 or 0.2 volts below the charging voltage set in your device.
• Discharge Floor: Set to 0%.
• Tail Current: Set to 2-4%.
• Charged Detection Time: Set to 3m.
• Peukert Exponent: Set to 1.05.
• Charge Efficiency Factor: Set to 99%.
• Current Threshold: Set to 0.10A.
• Time to Go Averaging Period: Set to 3m.
• Battery SOC on reset: Keep SOC
• State of Charge: Leave Alone
• Synchronize SOC to 100%: Leave alone. The device will sync itself at the top of the charge.
• Zero Current Calibration: Leave alone.

740GLE said:

On a Smartnetwork (just Bluetooth) the SCC charging settings adjust the shunt charged values. Not sure if the same is for a Cerbo system.

As far as your charged voltage, 26.4, that’s only 3.3v/cell.

Typically 27.2 is more accepted as fully charge at 3.4v/cell.

Doesn’t sound like muck but it’s a wold of difference.

Click to expand...

I have my Victron SCC set or 3.45v per cell (27.6v). So by setting this to the same voltage as the SCC that should et the SOC closer to the real rating?

Simonbr said:

Victron SCC set or 3.45v per cell (27.6v).

Click to expand...

I assume you have lithium batteries , set up the shunt for lithium. Charged voltage just below absorption voltage. 27.6 volts may be too low to alow balancing to take place for long enough, suggest 28.0 to 28.4 range , set charged volts in the shunt 0.2 volts lower. Efficiency 99%, Peukert 1.03. Discharge floor 20%.

Simonbr said:

Victron SCC set or 3.45v per cell (27.6v).

Click to expand...

I assume you have lithium batteries , set up the shunt for lithium. Charged voltage just below absorption voltage. 27.6 volts may be too low to alow balancing to take place for long enough, suggest 28.0 to 28.4 range , set charged volts in the shunt 0.2 volts lower. Efficiency 99%, Peukert 1.03. Discharge floor 20%. SOC after reset , turn off.