I'm trying to put two led bars into my boat but I need to buy a battery for them and also need help on figuring out what I would all need to hook them up thank you
LED lighting has very low draw on a battery compared to incandescent counterparts. There is probably no need to figure out how much draw these new additions will have on a good 12V marine battery (assuming this is what you have, and assuming" LED bars" aren't something with 100 extra bright LED arrays). I converted most of my marine lighting to LED. I can literally leave the navigation lights on for days without concern. Fuzzy's advice is great, but it would help to know exactly what your current system consists of. That is, do you have a system. If so, what does it power? Is it a deep cycle battery or a starting battery? Is it connected to an engine alternator? Etc.
What you do not say is what if any electric system you already have on your boat.
If you have the usual 12 volt system and your L.E.D. bars are rated for 12 volts then basically all you have to do is connect one end to the positive bus bar and the other to the negative. Of course running through a fuse and switch.
If you do not have any electrics then either purchase a battery pack or a marine 12 volt battery and connect to the terminals, through a fuse and switch.
the LED bars will have a voltage & current rating written on them. Probably 12 volt. In that case you need a 12 volt battery. The other value, the current will be in milliAmps (or mA). A 1000 mA = 1 Amp.
Battery capacity is given in Amp hours. Yuo need to work out how long you want your lights to work for in hours between charging. Multiply this by the current drawn by the lights (in Amps) to give you the requirements. Double this for security (also batteries dont like being run flat & actual battery capacity drops with age)
Now you know your voltage & capacity – that's the size battery you need.
You'll also need cable – get red & black multistrand tinned wire with a core diameter of about 1.6mm2 (or a little larger). A switch t osuit you tastes (screw or spade terminals)
A cheap crimping tool, lugs to suit your battery terminals, waterproof fuse holder & 5 Amp fuse) & the switch & the led bars.
Run the cable neatly & out of the way & protected from water, careless feet etc.
Red wire from battery plus to fuse to switch to led bar positive.
Black cable form led bar negative to battery negative.
You will also need provision for recharging the battery either insitu or by removing it to the bench.
Do NOT have joints mid run. One piece of wire all the way. All joints either crimped, screwed or soldered (but not with plumber's solder) Insulate all joints with heatshrink , liquid tape or similar.
1 its spelled LEAD
2 if u need lead buy lead
3 if you'r trying to protect metal parts look up boating on the web
Try this website, it will give you the basic information.