If you think about it the vampire girl seems to have no issue with the sun. Maybe when they are filled they become human-like and can walk in the sun. There are plenty stories of day walkers even if they are rare, maybe this breed belongs to that kind
If thats the case is just a matter of time before he runs out of batteries and become weak against the sun or even worse go back to a hideous form.
Also i hope poor Chika didnt get infected due to her recuperation. Hope it works partially like Vampire the Masquerade ghouls: Shes still a human not a vampire but she gets enhanced recovery and strenght that will eventually fade away unless she gets a regular dose (on Vampire the Masquerade, vampire blood was crazy adictive and created a huge dependance on the vampire who feeds the ghoul though, plus make them inmortal aging wise hope its not the case)