SOC, State of Charge

[Rancho Partera]

I have an question about my system, every few days the SOC numbers starts to go down and doesn't stop till it gets to 0% then it resets back to 100% for a few days until it starts to go back down to 0 again. The battery volatge is fine and is well within limits during the time (SOC will show low but voltage will be fine. I have been told by neighbors that this is a glitch in the system and that as long as the battery voltage number's are good we are all good. I would really like to figure out if there is a way for the system to stop doing this, as I hate getting error lights and messages. I have a Mate3S, a GS8048A inverter, a FM 100 and an FM 80 charge controller, and a FN-DC Flexnet-DC, and 24 Full River DC400-6 batteries.

[raysun]

How long has the system been in production?
How long has this SoC behavior been displayed?

The FNDC is the device monitoring the battery and deriving SoC figures. While I've not seen this exact behavior, it sounds like something is misconfigured - either in the FNDC parameter settings, or possibly, a shunt.

If the system is on OpticsRE, navigate to the Device Map, select the FNDC Battery Charging page, and post the parameters here.
Also, how many shunts are active in the system? From the Optics main status screen, click on the battery icon in the power flow diagram. A dialog will pop up with the shunt data. A screen shot of that will be informative.

[Rancho Partera]

The current system has been in place for about a year and the SOC percentage thing has been in place from the beginning, with no issues other. We have had outback equipment for 20+ years, this is new equipment.

on the battery charging page
Battery AH-400 which is default
Charged Voltage-52.8, default is 57.6
Charged time-1 minute which is default
Charged Return Amps-8 which is default
Charge Factor-100, default is 94

On the battery icon it shows SOC, current 100%, min 100%, Max 100%
Shunts Current
Shunt A- 15.1A
Shunt B-- (nothing shown)
Shunt C-- (nothing shown)

[raysun]

on the battery charging page
Battery AH-400 which is default
Charged Voltage-52.8, default is 57.6
Charged time-1 minute which is default
Charged Return Amps-8 which is default
Charge Factor-100, default is 94

24 Full River DC400-6 battery blocks?
That would be 48V @ 1200AH (3 banks of 8 blocks). Change battery AH: 1200

Charged Voltage should be set to 0.4V lower than the lowest Absorb Voltage setting. If using Full River's Absorb specification of 58.8V (2.45V per cell) with solar chargers set at 58.8V and inverter chargers set at 58.4V, the Charged Voltage: 58.0V

Charged Return Amps is typically set at 2% - 3% of the battery C20 AH capacity (1200AH). @ 3% CRA: 36A

Charge Factor is the figure of battery charge efficiciency. AGM batteries are typically 95%.

[raysun]

On the battery icon it shows SOC, current 100%, min 100%, Max 100%
Shunts Current
Shunt A- 15.1A
Shunt B-- (nothing shown)
Shunt C-- (nothing shown)

It's possible, but atypical, for a large system to use a single shunt. Typically a shunt is installed to track battery <-> Inverter current, and another for Battery <- Charge Controller current.
Is it possible more than one shunt is installed but not enabled? Temporarily enable Shunt B and C and see if there is any activity on those circuits. If nothing, then disable again.
If a single shunt is all, then make sure the Battery Negative lead is on the Battery end of the shunt (only), and all devices (Inverter, Charge Controllers) are on the Load end of the shunt. Take a picture of the wiring around the shunt and post. (It's very easy to miswire them.)

[Rancho Partera]

Thank you for your time I will take a look and post back.

[pss]

Historically, when that has happened to me, the problem goes back to the Mate 3S and the SD card.

I have found that sometimes powering off the Mate by removing the cable that connects it to the outback hub solves the problem.
Other times I have removed the SD card after a Mate 3S power down and placed it into my PC and found the file system corrupted. If this is the case, try to effect a repair of the file system, save what you can, then reformat the card, restore what files look good, usually the log files and then re-insert the card to the Mate.

If the condition still exists, then I have found that I need to re-flash the firmware on the Mate.

The Mate is a small Linux computer. As such, it does not contain all of the file read and write caching and confirmations of secure transactional computers like those in banks and critical missions. So every once in a while, something can get corrupted and needs to be manually restored.

Hopefully this will help you.