Question for Victron SmartShunt users...

[sunshine_eggo]

Sorry can't send a screen cap from my mobile but here they are:

Battery Cap 560Ah
Charged voltage 52.8

This should be 0.2V below absorption voltage for solar OR 0.2V below float voltage for AC charging. If you have both, set for solar.

Discharge floor 0%

This is a "time to go" number. When the shunt reports the time to go, it's based on this setting. I prefer to set it to something like 10-20% since one can't always count on their battery delivering true rated capacity.

Tail 4%

At lower charge voltages, this need to be lower than the 4% default. I'd try 2%.

Charged detection time 3m
Peukert exponent 1.03
Charge efficiency factor 95%

99%

Current threshold 0.10A
Time to go averaging 3m

Battery SOC on reset Keep SOC
SOC 28.5%

My inverter is pushing it to 55.2 with this setting anyway.

so the shunt is reporting 55.2 even though you have the charger set to 55.0V? If so, that's fine.

A bit high.

Agreed. My reasoning though is our system goes for days and even weeks during the rainy season, for example, at the lowest SOC (unable to fully charge because we're using up all the PV power) and long term these batteries last longest if they are not sitting forever below around 20% SOC according to Luyuan, so I thought it's better to keep them at that level. No good?

That's a good reason.

 

[DIYrich]

I have a 28.6kwh battery (2P16S EVE 280AH). My Victron SmartShunt says my deepest discharge was 408Ah.
This calculator says my theoretical battery capacity is 595.83 (Ah). My deepest discharge was only 68% of my battery capacity.

You have a name plate rating of 560ah, and Victron says you used 408ah. That is 73% of the name plate rating.

Low voltage disconnect is set at 51.6V.
Am I within reasonable spec on my battery capacity and do these settings look reasonable?

51.6v is about 30% SOC. If the inverter stopped using battery at 51.6v, that is about the 408ah of the deepest discharge. 408ah is 70% of 583ah, which is close to the 595ah theoretical battery capacity you calculated. The rest could be that you are charging at 55.0v, and not 58.0v, leaving a few ah on the table at the upper end.

I have my low voltage cutoff at 48.0v, an average of 3.00v per cell. That is about 10% SOC, and leaves headroom to reduce the risk an individual cell reaches 2.50v. It also provides reserve capacity for the inverter to "blackstart" itself if the grid is down.

 

[sunshine_eggo]

51.6v is about 30% SOC. If the inverter stopped using battery at 51.6v, that is about the 408ah of the deepest discharge. 408ah is 70% of 583ah, which is close to the 595ah theoretical battery capacity you calculated. The rest could be that you are charging at 55.0v, and not 58.0v, leaving a few AH on the table at the upper end.

Good point.

Given the OP's desire to cut off at a higher SoC for "storage" purposes, it would make sense to change discharge floor from 0% to 30% to yield a more accurate "time to go" value reported by the shunt.

 

[kolek]

Guys it's late here in JP, I need to sleep please don't be offended if I don't answer until tomorrrrowowrowow morning. Goodnight everyone and thank you for the tips!

 

[sunshine_eggo]

Guys it's late here in JP, I need to sleep please don't be offended if I don't answer until tomorrrrowowrowow morning. Goodnight everyone and thank you for the tips!

Sleep is for the weak, but your spelling of tomorrow suggests you may be in dire need.

 

[kolek]

You have a name plate rating of 560ah, and Victron says you used 408ah. That is 73% of the name plate rating.

51.6v is about 30% SOC. If the inverter stopped using battery at 51.6v, that is about the 408ah of the deepest discharge. 408ah is 70% of 583ah, which is close to the 595ah theoretical battery capacity you calculated. The rest could be that you are charging at 55.0v, and not 58.0v, leaving a few ah on the table at the upper end.

I have my low voltage cutoff at 48.0v, an average of 3.00v per cell. That is about 10% SOC, and leaves headroom to reduce the risk an individual cell reaches 2.50v. It also provides reserve capacity for the inverter to "blackstart" itself if the grid is down.

This is actually the answer I was looking for. You're right, 408ah is 73% of 560ah, and my low voltage cutoff at 51.6V is about 30% SoC, so it seems like my battery bank is delivering the capacity it should. Thanks @DIYrich