Charging 14s pack with LiFePO4 charger

Is there any reason not to charge a 52V (14s) Lithium Ion pack with a 48V LiFePO4 (16s) charger? The terminal voltages are almost the same.

Yes, fine

LFP 16S 58.4V is usual, personally I use under 57V, at low C-rate 55.2V max

LI "52V" 14S, usual is 58.8V, but I would use around 56.7V at low C-rate, 57.4V max

Obviously, balancing with a non-adjustable BMS,

as opposed to a dedicated balancer or balancing charger,

may require holding Absorb above the start-balance setpoint until balancing is complete.

Probably depends on your BMS. If your BMS will start to balance at 58.4v then you will be OK. However if it doesn't start to balance until 58.8v the you could have some balance and or cutoff problems down the line as the BMS balance function will not kick in.

If the LiFePO4 charger has an adjustable voltage trim pot you might be able to bump it up to 58.8v with a slight twik to the pot.

Or, if the BMS won't let you tweak tge start-balance setpoint down, just use something else for balancing

to get better longevity