dc to dc charging from 144 volts to 12 volts

Could I hook up a dc to dc charger from the large hybrid battery to charge a 12 volt lithium battery ? I have the 2015 Prius C model vehicle and I would like to be able to charge a lithium battery between 20-60 amps for a fast charge instead of using the 12 volt system.

 

I just found this: 121475001037 on ebay, it's listed as DC Converter Volt Reducer 144V to 12 volt 60 Amp 720W Electronic car 144volt. Input voltage range: Along with this: 120V to 170V.ECO-WORTHY 12V 40A DC to DC Charger with MPPT On-Board Battery Charger LiFePO

 

Thanks for the tip about the fuses. I will report back when I have the pieces together, looks like the entire system with 2 100 ah batteries will cost about 1000 dollars. This rig should be able to run my small freezer, microwave and Keurig 30 minutes per day without major problems. My in car freezer currently runs with a small portable inverter/booster power pack and/or the 12 volt socket in the car as the freezer only draws about 45 watts on and off.

P.S I also plan on installing a second battery (house) with an isolator and a 200 watt ac inverter along with a ups (automatic transfer switch for the 2 ac inverters) This will allow trickle charging of the lithium bank and other incase of failure of the main charging system.