Ok so i got no battery in the truck and id like to know if i can use a battery charger directly put on the battery cable.. no battery in place.. ive done some search and people seem to say it my not be good coz of the dc output isnt stable and stuff like this.. but idk i dont think it can be that bad but should i do it on 12a 2a i dont wanna try to start it i just wanna check if everything on the truck work.. lights radio and stuff