Where i spliced the wires out of,

The wires im planing to connect to this battery read 12.26, so it will charge. But yeah does it need a regulator or anything?
I spliced some wires, i think they were for a 12v (cigarette lighter) and extended them into my bead, (ether way)multimeter reads 12+v
now I want to connect it to a deep cycle,
Do I need a one way diode ?
I'm going to put a 10 amp fuze on it. Is that correct to do?
Anything I should watch out for?
I don't want to fry my car!

 

What year? What are you trying to accomplish? Where will it be mounted? Thinking you meant bed but just want to make sure.

 

This is a double post. OP has this exact post already in here....