Battery Question

[Eargunk]

I have done some research and i found out the max cca for a battery that would fit under the bonnet would be 450, im looking to run one battery in my trunk and have an additional marine battery in the trunk to assist in running my sound system (1 monoblock amp) where the battery is connected to the engine or bonnet battery some how so i won't need to constantly recharge it. What gauge of wire must i use, is it possible to use house power cables (according to my friend) or is there anything else i would need to run an additional battery in my trunk, a slight explaination of wiring up would also help me alot.

If the above is not possible what type of wiring would i need to run a battery from my trunk instead of under the bonnet.

[daviboy]

Why dont you just upgrade the battery under your bonnet to a bigger chunkier 1. And if it its just 1 monoblock amp your running off the battery, the factory battery will do.

Im currently running a 4 channel and a 2 channel amp running off them at 80A each through 1 run of 4guage wire.

[Rolla Boy]

You could fit a heavy duty Optima battery in there, 700CCA Battery would fit in there with no worries...

[akuma]

im no good with battery, but i bought a optima dry cell battery for $350 @ JB (cheap?) and its going to replace my factory battery so i can handle 1mono <1200watts and another 4 channel amp inc my HIDS and neons .

[GtiRboy]

i will tell you one thing,

you will need a battery isolator (explanation here - Link)

Otherwise you will find your main battery going flat if you run your system with the engine off.

I also wouldn't use house wiring cable. Get the proper cable for the job. You don't want your cable insulation melting then burning your precious car down to the ground!

[STYLSH]

Just get a single good battery. I'm usually against using 2 batteries unless you are actually going to use your system with your car off all the time or if you have a 4wd. It puts more stress on the charging system. A single good battery is more than enough for your system. You've only got a monoblock amp which in the first place would most probably be a class d amp and thus have very high efficiency anyway. I'm running 3 big Trutech's which are class a/b's and only using a single optima. It runs well and can be used with the car on for long enough.

[the_random_hero]

Get a single battery, using two batteries actually places MORE stress on your cars electrical system. 450CCA is plenty for a sound system your size, but if you want to spend the money get a good Optima battery.

What you need to do depends on what amp you have, but a good guide to what size power cable you need comes from the size of the terminals on the amplifier itself. If it's 1200WRMS, then I'd be using 0/2 gauge from the battery with a 200A fuse within 30cm of the battery. This will allow ample current to get to your amplifier. If it's 1200W MAX, then you only need to run 4 gauge from the battery, with an appropriate fuse (100A) within 30cm of the battery.

Following that, you should run a piece of 0 gauge from the battery to the chassis, and a piece of 4 gauge to the engine block. This will help any earthing voltage drops you might end up with. Whatever you choose, make sure the amp has the same size earth wire as the power wire, and fix it to the chassis well. See if you can find a spare bolt hole (most cars have them around the boot area), sand the area around it down to bare metal and then bolt the earth wire to that. Remember to spray some cavity wax or something over the bare metal so it doesn't rust.

I do this stuff for a living, so my advice is generally close to the money :P

[Eargunk]

thanks for all the replies, its helping alot. Thanks again

[Woggy]

I would reccomend running a dual battery setup ONLY using a Dual Battery Isolator.. not only are they useful in keeping adequate power in high current stereos, but they can save you from running your front/main battery flat. Some even have an override function where if your front/starting battery is flat the isolator will switch the batteries together and start using power from the back battery. I got a hold of a REDARC Dual Battery Isolator from TJM pretty cheap, and i highly recommend using the REDARC.

[STYLSH]

^^ Only need that if the op is going to be running his stereo with the car off for an extended amount of time. An optima yellow top can run a 1200w rms system in excess of a few hours and still start the car easily. I've done 4 hours at moderate volume on a 1400w rms system and it still started fine.