Help with 128 batteries each one is 280ah, and want to configure for 48v system.

[Yurtdweller]

This is part of a document that I received with my cells. This doc was written by Steve S. and is distributed by Amy Wan at Shenzhen Luyuan.

 

[Sanwizard]

Andy at "off grid garage" has done some excellent testing on this subject

 

[DerpsyDoodler]

I would not float lithium at the same voltage as absorb unless your use case is a home or similar environment which has loads and you are charging from solar. 3.35 is very close to the voltage in which the cells settle at at might not trigger balancing. I charge my EVE cells to 3.40 volts with a long absorb time. I only charge from solar. My inverter does not have a setting for Float when I choose Lithium profile.

Lithium really isnt meant to be floated. lead acid likes to sit full, lithium likes to be cycled, or at the very least they don't want to sit long periods of time at a high state of charge.

 

[hummmingbear]

I would not float lithium at the same voltage as absorb unless your use case is a home or similar environment which has loads and you are charging from solar. 3.35 is very close to the voltage in which the cells settle at at might not trigger balancing. I charge my EVE cells to 3.40 volts with a long absorb time. I only charge from solar. My inverter does not have a setting for Float when I choose Lithium profile.

I am in a home and charging from solar. House is off-grid.

In that case you suggest floating at the Abs voltage? Why is that your suggestion, because of the limited time it sits in Abs before the sun goes down?

 

[hummmingbear]

Lithium really isnt meant to be floated. lead acid likes to sit full, lithium likes to be cycled, or at the very least they don't want to sit long periods of time at a high state of charge.

That makes sense. If I want to maintain 90% SOC what float voltages are recommended?

 

[hummmingbear]

Andy at "off grid garage" has done some excellent testing on this subject

This is a great video, watched it the other night. The only thing to keep in mind is he's just testing 1-cell, results would differ quite a bit with a 64-cell battery.

 

[kromc5]

This is where where I have float at for my daul 4p16s.

 

[Ampster]

In that case you suggest floating at the Abs voltage? Why is that your suggestion, because of the limited time it sits in Abs before the sun goes down?

No, I would float at the resting voltage which is about 3.35 per cell. It is below my Constant Voltage (Absorb) setting of 3.4 volts so the cells will get some charge to offset the overhead of the inverter and small loads. I am grid tied and do not use a float setting and the solar covers my loads until the sun goes down and then the battery takes over to serve the loads.