I have upgraded from a 24v AGM battery bank to 48v LiFePO4
For many years I have benefited from this Orion 24v-12v converter.
It has a very high efficiency 96% and a low "off load current" of <15ma
I cant find a product similar efficiency for 48v to 12v conversion - Have I missed the obvious choice?
The Orion-Tr 48-12-20 has 87% efficiency and an off load current of <80mA.
Orion 24v-12v DC-DC
In the same boat. Asked my victon distributor about using a smart solar mppt. they said it would probably work, they dont know, and its not supported.
have not hooked it up yet but will let you know if I get to it soon.
also bonus, equalization every 30 days on the 12v lead acid. I dont think my 110v smart charger does that, not sure about the orion ( i have the non smart version).
I hooked this up the other day and it has been running great. Now I can keep my critical 12v systems on when the pack is low and inverter is off. (was using a victron smart charger to keep the battery charged).
not shown is I brought the 48v line off of my lynx distribution w/ fuse. 
The MPPTs are completely different, will not give you a stable continuous supply due to the regular solar tracking kicking in.
The standby current of the model you are considering is so low, it's not worth worrying about. And efficiency differences mean that you will only consume a little more power.
It's Not Much, But It Adds Up:
24 x 365 = 8.760 hours
80mA - 15mA = 65mA
8760 x 65 / 1000 = 569Ah
569 x 48v = 27kWh
I bought this DC-DC Converter - it will do the trick - I don't have any 12V batteries left - only 12V consumers
For 12V consumers only, you can use any Step-Down Converter with 48V->12V. There are many of them on the market, for example from MeanWell.
If you also want to charge the 12V battery, use the Orion 48/12-20 (isolated, not smart)
