A leisure battery is a term used to describe batteries that are designed to hold and discharge power over a long period of time. Typically they are used as "house" batteries for RVs and boats, storing power generated by the engine for use later when the engine is not running. You can wire a leisure battery easily; there are only a few basic connections you have to make to keep your lights running long after you have come to a stop.
Run the wire from the battery isolator in your engine compartment (this is what will allow your leisure battery to charge from the engine when it runs) to where you will be storing the leisure battery in your RV or boat. Strip a 6 mm (1/4 inch) of insulation off the end of the wire with your electrical pliers.
Open the wire plate at the base of your battery terminal connector by using a 10 mm (7/16 inch) box spanner to loosen and remove the screw bolts. Place the bare end of the wire from your isolator in the indent in the base of the plate. Strip a 6 mm (1/4 inch) of insulation off your roll of #14 wire and place that end on top of the other wire. Screw the top of the plate back on so the wires are pressed into the battery terminal connector and you cannot pull them out.
Put the battery terminal connector you just wired on the positive post of your leisure battery and tighten the screw on the connector to hold it in place. Run the #14 wire to your fuse box. Cut the excess wire off, strip a 6 mm (1/4 inch) of insulation off the end and attach a spade connector to the end. Connect the wire to the input spade of the fuse box (typically this is marked with an arrow).
Cut a length of #14 wire that can run from the negative post of your leisure battery to a screw or bolt that is on the metal frame of the vehicle or boat. Strip a 6 mm (1/4 inch)of insulation off both ends. Attach a ring connector to one end, remove the bolt or screw you will use as the grounding point for the battery, pass it through the ring connector and tighten it back into position. Connect the other end to your battery terminal connector using the same method of opening the wiring plate and inserting the wire as you did on the connector you used on the positive post. When the wire is securely attached to the connector, place the connector on the negative battery post and tighten it in position. Your leisure battery is now wired.
To help keep your leisure battery in its best condition be careful not to completely drain the battery; make sure there is a minimum charge in it at all times.
All batteries can potentially explode due to the nature of the acid inside and the gasses they produce. Do not store any battery in an area lacking proper ventilation as this will increase the risk of explosion.