SmartShunt battery settings incorrect

Q&A and troubleshooting
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1

Really happy with the way I can use the CERBO to view information about my setup from afar. But I think I have not setup the smartshunt battery settings correctly.

battery settings
battery settings1170Ă—2532 255 KB

At night time I am reading the battery at 75% but the phoenix inverter is shutting down due to low battery voltage (not always, just after a few low solar days). There is no big load on at that time, maybe the fridge or a small light. Therefore I think the phoenix is reacting correctly, just the percentage is wrong due to my bad? input…

My battery is a TUDOR OPZS 12v 985 amph.

I have attached a photo of the settings that I have put into the solarshunt.

Thanks in advance

Brent

2

Hi Brent

At the first view the battery monitor settings are ok.

Discharge floor should be 50% for lead.

Who deep is the battery voltage when the inverter Shuttle down?

What says the smart shunt min/max values?

1 Like
3

As said above, the settings look good for a lead acid battery, do you have a load that is bypassing the shunt so is not being counted, see linked FAQ. Do you have a large voltage drop between the battery and the inverter.I

1 Like
4

Thank you for your answer, Dirk. Do these pictures answer your question? The two diagrams are from the same time period. The inverter shut down on the night of 12/13. You can see that there was no sun on the 12th (which is rare in Portugal…). But SOC is showing just under 80% and voltage drops to 10.88v. (I can only see that if I zoom in a lot)

BATT SOC
BATT SOC1170Ă—1742 130 KB

BATT VOL
BATT VOL1170Ă—1748 171 KB

5

Thank you for taking the time to answer!

The shunt is the first connection to the battery. Everything else is on the other side of that including solar, 12v load and inverter.

The inverter is connected by a 1m cable. It’s really thick (I can’t remember the gauge but it was the correct one according to Victron at the time of installation. And any big loads such as water pumps are designed not to work at nighttime.

6

Hi Brent,

The battery voltage drops significantly, which then causes the inverter to shut down. With a battery capacity of over 900 Ah, the voltage should not drop so sharply with such a small load.

Depending on the interval you have set for logging in Cerbo (default 15 min), you will lose some of the real data.

How old are the batteries? They may be sulfated.

Have you measured the voltage directly at the battery terminals (unloaded and under load) to see if it matches the voltages measured by the Smart Shunt?

If there is no reason for the sharp drop in voltage, then I fear that the batteries are at the end of their life.