gonna be doin this soon....but how? do i need to run a wire to the front battery or something so that the rear one gets charged too?? lol...i have no clue
I have a second battery in my 4wd car. What i have done is just earth the negative of the second battery to the cars chassis and then you can either connect the positive terminal to the positive terminal of you original battery or i have put the positive terminal of the second battery going to a 180amp relay then going to the battery and i have hooked te trigger for the relay to the ignition power (this can come from the radio) this way will isolate the two batteries when the car is off, so in theory you can never get a flat battery. Be carfull running the positive wire and make sure there is no sharp edges it would rub against because there is no fuse. Also make sure the wire you use isnt to thin in diameter to carry the high current. Its pritty easy to do anyway....Good Luck with it.
thanks, is there any negative effects of just running the postitive of the new battery to the positive of the original? it just seems much easier. also would it just be okay to just run a HO alternator and a optima battery if i would eventually be running around 2000wRMS?? or would that secnd battery be needed like i would assume?
you need a battery isolator, you need appropriate gauge cable and ground, and you'll need a battery box to isolate the battery and vent it in case of gassing. any RV shop or speed shop should be able to sell you the isolator and battery box. you'll need an alternator that can handle recharging both batteries as well. you'll want a deep cycle for the rear isolated battery like an optima yellow top that can be deep cycled without damage to the cells.
the isolator is pretty simple. you just connect it between the second battery and the starter battery as it's diagram will indicate. get an isolator rated for at least the current output of your alternator (100, 150, 200A, whatever) the isolator will prevent the batteries from seeing one another but allow both to be charged from the alternator. They're fairly inexpensive. the battery box can be found at summitracing.com or yearone.com or any car parts supply house. They are VERY common in the racing world to move weight to the rear of the car when moving the battery and clearing engine compartment room. Also safer to have the fuel cell and battery isolated and protected in the trunk. they come in plastic or metal. the cable you can get pretty cheap from knukonceptz.com the optima battery will run ya in the ballpark of $150-170 for a red or yellow top. the red is ideal for the starter battery the yellow is ideal for the isolated audio system battery or batteries
I use a red top and two yellows in my own car in a similar setup. high output alternator to a battery regulator, then to the starter battery and two yellow tops. that allows me a good run time with the car shut off, as well as plenty of current for the system while driving.
