There's never any documentation of the electronics that come with the chinese models that I've seen... I think the amp esc for hyd pump is something like 125amp. The brushless motor for the pump is overly large & therefore turned back to 19% EPA (approx) in radio settings. 12v car battery will be typically 13,5 to 14,2v full charge. Start with a 10amp fuse... maybe
I think it's a diode that's needed to reduce voltage from the car battery... if you know an electrician, he might have something on hand... maybe a light dimmer switch would work, use a voltage meter to set your output.