48v Lithium Ion correct charge (bulk, absorption and float)

[Billbait]

Hi all,

First off, I’m new here. I tried to find this information on my own but I couldn’t…

I’ve been off grid for about a year now. We have a fairly large solar setup. I was doing some unrelated research and found a chart that showed the correct voltage that a charge controller should be set at (bulk, absorption and float) to get the proper charge on our battery storage. I’m concerned mine is not set correctly and may be damaging my batteries.

I have 10x Tesla Model S Battery Modules, 24V, 250Ah 5.2 kWh wired in series to 48v. We use Victron smart charge controllers. What should I have my bulk, absorption and float set at for this?

Thank you in advance.

 

[kpw]

this may help

LiFePO4 charging voltage

Hello, I'm new to LiFePO4 battery charging and have a question. I am converting a 36 volt golf cart to Lithium and have decided on the Fortune cells. They say that the max charge voltage per cell is 3.65v but my charger will only get to 3.6 volts. What effect with this have on the battery as SOC...

diysolarforum.com

 

[Ampster]

The above advice is for LFP cells. You need to find advice specific to Tesla Modules. The specifics for those cells is 4.05 to 4.10 Max Constant Voltage but since most Teslas only charge to 90% you will probably get longer life if you go to 4.0 per cell. Tesla Modules are 6 cell groups in series so the math for two modules in series would be 48 volts max.

Absorb is a Lead Acid term and is a constant voltage phase where the Amperage tapers. Some controllers has an Absorb ending based on time or Amps.
If your stationary storage is constantly loaded you can use a float voltage slightly below the constant voltage setting to keep your pack charged from solar until the sun goes down. Otherwise many people do not recommend using a float charge on any Lithium batteries.

 

[Billbait]

The above advice is for LFP cells. You need to find advice specific to Tesla Modules. The specifics for those cells is 4.05 to 4.10 Max Constant Voltage but since most Teslas only charge to 90% you will probably get longer life if you go to 4.0 per cell. Tesla Modules are 6 cell groups in series so the math for two modules in series would be 48 volts max.

Absorb is a Lead Acid term and is a constant voltage phase where the Amperage tapers. Some controllers has an Absorb ending based on time or Amps.
If your stationary storage is constantly loaded you can use a float voltage slightly below the constant voltage setting to keep your pack charged from solar until the sun goes down. Otherwise many people do not recommend using a float charge on any Lithium batteries.

Thank you. I had such a hard time finding an answer directed toward Tesla specific batteries.