Connecting Two Battery

Hi, I need some help connecting two battery, What do I have to do to connect to batterys.

thank you

Short and simple answer is... buy an isolator and a sealed battery.  Two of the most popular types of sealed batteries are Gel Cell and Coil.  Optima makes good sealed batteries.  The reason for a sealed battery vs. a regular battery is that most people install the second battery inside the vehicle.  Non-sealed batteries can emit hazardous fumes if they develope a leak or tip over (not to mention the battery acid that can get into your vehicle).

The isolator is installed between the alternator and the 2 batteries.  It acts as a brain, and determines which battery needs the charge, and routes the power accordingly.  Isolators come with installation instructions for the wiring to the batteries, but you will need to know which wire to disconnect from the alternator to the stock battery and then reroute it to the isolator.

if you want to go the simple route and dont want an isolator, just put in the other battery and connect its positive terminal to the origional batteries positive termainal and connect the new batteries negitive terminal to the frame of your vehicle and then you will have the combined power of both batteries and you alternator will charge both batteries equally.

keep in mind that if you play your system for a while with your car off then both batteries will be drained at the same rate and it is still possible to drain them both and not be able to start your car, but this will take atleast twice as long as it would with only one battery

Just something that no one mentioned...When batteries are wired in parallel, it increases the current capabilites. (Eg - You have three 12V batteries, each one at 600A......The voltage stays the same which is 12V but the current changes to 1800A) Also note that you can't wire a 12V and a 6V battery in parallel.....there will be FIRE.

If you wire those same batteries in series then you're current will remain the same and your voltage will go up. Final Results being 36V and 600A.

I know it wasn't really part of the question but it may help someone who reads it someday.

So you shorted BOTH wires? Yikes....well I need some details here.

1) Explain exactly what happened to you're positive 12V wire and your ground wire...did you short circuit the positive directly to ground? And did you short the ground to positive? Are both of the wires melted and ruined? These are important aspects.

Running wires to an amp isn't very difficult...there are just a few things that you have to remember...

-Positive wires runs from the positive from the battery...it should be fused as close to the battery as possible to help prevent fire if there is a short. You run it from the + on the battery through the firewall of a car (where the gas/brake pedals attach...u just have to find a hole or make one yourself BUT CHECK WHERE YOU DRILL IF YOU DO HAVE TO MAKE ONE). And once it's through the firewall you just run it up the kick pillars on either the passenger or driver side of the car.

-Just a quick note....your RCA cables should be running on the opposite side of your car as your positive wire. (eg positve running on driver side kick pillar and RCA's running along passenger side kick pillar). If you don't...you can get system noise running into your amp and your speakers will pick it up.

-Negative wires are usually really close to the amplifier...you are going to want to use the same gauge wire for your negative as you did your positive.<<THIS IS IMPORTANT. Just find a ground, make sure that it is sanded free of any paint and attach it with a ring terminal.

-Remote Wire is just a wire from the deck that runs to your amp...usually popular to run it on the same side as the positive seeing that it does carry a little bit of voltage, but it is usually neglectable and whatever is easier.

Those are the basics.....any more info just let me know......