MPP LV6548 with SOK SK12V206 - battery parameters?

[Mike.Indiana]

I have 8 SOK batteries made into two 48v 206A banks. I'm feeding two MPP lv6548 inverter/chargers to power my home. Essentially the system for now is operating as a whole house UPS (ground mount solar panels will be installed in the spring). Everything appears to be working so far..

My question is concerning the correct battery settings for the MPP.

I calculated bulk charge voltage to 58.4v (14.6v * 4).

I set max bat discharge current to 100A and charge current to 30A per SOK specs.

I am unsure about the following MPP settings:

Cut off voltage ?
Float charging voltage ?
Battery Equalization (EQ) - enable?

Assuming battery EQ enabled..

Realtime activate battery EQ ?
EQ time out?
Battery EQ time?
EQ period ?
EQ voltage
Back to grid voltage?
Back to discharge voltage?

Can anyone shed some light on the proper settings?
Thank you.

Michael Fox

 

[sunshine_eggo]

I calculated bulk charge voltage to 58.4v (14.6v * 4).

14.4 * 4 is better as 14.6V requires the batteries to have perfect balance, and you'll likely trigger over voltage protection as one cell

Cut off voltage ?

48V leaves you with 5-10% remaining.

Float charging voltage ?

3.375V/cell = 54.0V

Battery Equalization (EQ) - enable?

disable

CRITICAL THAT YOU FULLY CHARGE EACH 12V INDIVIDUALLY TO 14.4V AND THEN CHAR GE 4 IN PARALLEL TO 14.4v BEFORE YOU STRING THEM IN TO 4S 12V FOR 48V. Failure to do so may cause one or more of the 12V to trigger OVP and terminate charging prematurely.

 

[Mike.Indiana]

Hi Bentley. Thank you for your advice!

About the critical balancing step, I connected all 8 in parallel and charged them (power queen 14.6v 20A LIPO4 charger)
all fully - it took about 3 days. The next day (maybe 2 days later) I connected them into the two 48v banks.

The two banks should but do not appear to have the same capacity, I have a victron shunt on each bank. When I tested the system shutting the grid power down and running on battery backup for about 3 hours the shunts indicate about 1 hour difference between expected discharge time (7hrs versus 8hrs). Further testing yields similar results. The batteries were all new from the same vendor however the batteries for one bank were purchased separately about a month apart. Thoughts or suggestions? TIA