Battery cells voltage drop from 100% to 80%

[RadPL]

Hello, I have noticed a power drop in my installation and I have no idea why or how it happens.
I have a 16 48v cell LiFePo4 power bank and an EaSun 8kw inverter.
Batteries charge to their full capacity of 56v and then sharply drop to 53v (regardless of power consumption that day) and stay that way all day.
I was expecting for the cells to charge back to 100% in daytime and a consistent power drop to 10% at night.

First graph is the voltage of my battery through the day, second shows its percentage.

 

[Bananaman321]

Hello, I have noticed a power drop in my installation and I have no idea why or how it happens.
I have a 16 48v cell LiFePo4 power bank and an EaSun 8kw inverter.
Batteries charge to their full capacity of 56v and then sharply drop to 53v (regardless of power consumption that day) and stay that way all day.
I was expecting for the cells to charge back to 100% in daytime and a consistent power drop to 10% at night.

First graph is the voltage of my battery through the day, second shows its percentage.

It's a possible that they have satisfied the bulk stage and have dropped to float I do not know what your settings are but.
Not a whole lot to go off of here that's the best I can make of it.

 

[Luk88]

This is completely normal with lifepo4 . You likely still have almost full charge at the beginning of that drop. It depends on the exact lifepo cells. I have seen so. E that drop to prescribed 3.45 per cell. I also have Higee cells that drop to 3.35 per cell and they still have goid capacity.

It is also possible you're not charging them fully, but we're talking single digit percent numbers here. Not 20%.

 

[AntronX]

Voltage drop to 3.31V is normal, the battery is full. But your BMS is reporting incorrect SOC. I suspect it only listens to battery voltage and does not do coulomb counting.

 

[RadPL]

Thank you all for the advice

 

[wpns]

Mine do that too:

Not sure why your BMS isn't counting coulombs, but it looks like it's just measuring voltage, which is the worst possible way to measure SOC.

 

[hardtop]

For my Lifepo4 pack I found that voltage is not a go-to metric at all like a lead acid or AGM battery. I pretty much forget about it unless I'm waiting for charging to complete. I read AH remaining on my JK. It seems accurate enough and it has a % remaining field off that AH count so that is what I use to determine how much battery I have.

 

[BatteryBuff]

Hello, I have noticed a power drop in my installation and I have no idea why or how it happens.
I have a 16 48v cell LiFePo4 power bank and an EaSun 8kw inverter.
Batteries charge to their full capacity of 56v and then sharply drop to 53v (regardless of power consumption that day) and stay that way all day.
I was expecting for the cells to charge back to 100% in daytime and a consistent power drop to 10% at night.

Those voltages are fine. 56V is the boost voltage that I usually use. 55.5V is fine for the float voltage. 53V after the sun goes down is normal for a LiFePO4 battery when at rest at 100% SOC.