Hi,
A normal 48v LiFePO4 is made up with 16 cells, which gives a max charging voltage of 58.4v (3.65v/cell) but from the information you provided above, it seems that these Allied batteries are only using 15 cells, giving a maximum charge voltage of 54.8v.
Your resting voltage of 52.4 indicates a filly charged 15 cell battery or a 50% charged 16 cell battery. Lithium batteries are best stored and shipped at 50% capacity so there’s a discrepancy there.
If it’s a 15 cell battery You’ll need a lithium charger (CC/CV power supply) with a CV setting of 54.8v. If it’s a 16 cell battery you’ll need a 58.4v CV setting.
Allied should be able to tell you if you need a 15 cell charger or a 16 cell charger.
The discharge curve for lithium is very flat so you cannot accurately predict state of charge with voltage, you’ll need a coloumb counting SOC meter, hence the no published voltage chart. This is the one I use and recommend.
https://www.renogy.com/500a-battery-...xoC0UYQAvD_BwE
Cheers
Pat.