dracekvo, similarly to you, I also have a 48v battery --> 4kW inverter to produce 240vac --> J1772 EVSE --> onboard charger --> i-MiEV battery pack. Haven't measured the 48v power draw to compare to CaniOn charging current&voltage readings, but I'm sure it's not very efficient. In my case, I already have it, it works and is paid for, and I have no need for efficiency, as I have plenty of 'free' existing solar to recharge the 48v pack and I'm not in a hurry. The key point for me is that I have the ability to recharge my i-MiEV when the grid goes down.
Searching to improve efficiency, any other solution will take time and money. The only consumer CHAdeMO charger I'm aware of is SETEC, and it runs off an ac input.
Simply adding more solar panels to recharge the 48v pack a little faster may be the most cost-effective solution for the dc-ac-dc charging system inefficiency.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV