what size wire do i use to connect a second battery in my trunk for sound system?

Question

well i have a optima battery in my tunk powering 3 amplifiers 2 for bass and one for voice..

but i want to know what size wire do i need to run to keep the battery in the trunk charged ???

would it need to be a small 18 guage wire just to trickle charge it ??

or would it need to be a heavy 2 guage wire so in a way the batteries would work together ...

and also i was planing on just running one wire from positive + side of my car battery to positive + side of my trunk battery..
and just grounding my trunk battery to the frame..


thanks !!!

Answer 1

If you do this you will HAVE to upgrade your alternator, as it will put a big load on your alternator, unless your running LOTS of power, you should be ok with just the regular car battery, but upgrade all of your battery cables, and ground straps on the car, as they will burn out. Im not positive on the + to + on the battery, i think that is right, but see what other people say about it. grounding to the frame will be alright. I would use the thickest wire i could find, 2 gauge atleast, if your just trickle charging it, the battery will go dead and your amps will power on and off when ever the battery gets power, and off when its out. full power all the time, but that pulls a big load off the alternator, be prepared for an EXPENSIVE alternator, high amp alts are usually a couple hundred dollars

Answer 2

If your total system power is 1000 watts RMS or more, you will need to:

1. Upgrade the alternator to a high output alternator
2. Upgrade to a heavy duty deep cycle battery
3. Upgrade the "Big 3" - that is to replace the power wire between the battery and alternator, the ground from the battery to the chassis and the ground strap from the engine/tranny to the chassis with at least 1/0 AWG wire.

Failure to do this will result in you replacing them anyway as the alternator will eventually fail.

Here is a guide that will calculate what size alternator and power wires you need http://www.datafilehost.com/download.php?file=6d26c621

A second battery is never a good idea as it's an added strain on the alternator to charge two batteries AND supply power for the car. The ONLY time a second battery is useful is if the audio system is to be used with the car off.

A cap is only good so far as the audio system isn't trying to pull too much from the electrical system. A cap doesn't provide more power, it's designed to 'stiffen' the voltage to the amp, nothing esle. If the current isn't there, a cap won't help. The alternator must have at least 20% more amperage power than the entire vehicle and sound system combined for a cap to be of benefit which is ironically the same requirements for an amp to be efficient.

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Answer 3

Won't work. The alternator can't tell which batt. is which. You need a battery isolator in the system, get at auto supply or radio shack. It will come with wiring instructions. It will allow the alternator to keep both batteries charged and you won't need to connect them together. I would use a 12 ga. wire for charging the trunk battery. The wire will stand more abuse than a smaller wire.

Answer 4

I highly recommend and alternator upgrade first...If you have done so, use some 0 gauge or larger and do the "big 3"

Answer 5

lower back we mixture a great variety with rubbish, why do you adult adult males do this? besides provide up staring on the top ability or MAX ability, seek for RMS or non-provide up ability your amp might desire to grant 1200 watts RMS yet i doubt it, use 4 guage ability and floor no could spend extra money on a sequence up kit then what the amp value new, additionally make advantageous your employing actual rockford fosgate and not rockwood subs