2nd Battery location and Wiring impact for Stereo Q?

[the_dude]

So I'm mapping out a stereo upgrade for my boat (VLX - vdrive) which currently has a single battery and two lower wattage amps. The Starter battery is located in the rear engine compartment.

In adding a 2nd battery I'm trying to decide between two options.

Option 1:

Add 2nd battery in rear engine compartment. Run 0 gauge power & Ground wires ~20' each to amp compartment behind spotter. Wiring at $4/ft is $160.

Option 2:

Add 2nd battery to compartment behind spotter. Run 4 gauge power & Ground wire back to 1st battery. Purpose of 4 gauge wire here is to provide charge to 1st battery and ability of batteries to share some duties. Wiring at $1.50/ft here saves me $100 towards the cost of the 2nd battery.

So is my thinking here sound? I'd like option two for the cost savings and this way when the stereo is cranked the battery that is responsible for supplying those high and lows is right next to the amps. 4 gauge is overkill for simply keeping the battery charged off the alt and my thinking is that it is enough for helping the battery 1 start the boat (help only) if needed and vice versa the starting battery providing a bit of backup power to the stereo. From working in a parts store during college I can remember that a lot of vehicle battery cables were only 4 gauge and some were 6 gauge.

At this stage the total RMS wattage I'm looking at is between 1090 and 1750.

[jonyb]

You can use option 2 without a problem. Make sure to use an isolator between the batteries to keep the stereo from drawing from the starting battery while the key is off.

Isolator: http://www.stingerelectronics.com/productDetails.aspx?delineate=735&CategoryID=-1&ParentID=-1

As for batteries, do you have something picked out? I sell Kinetic and Stinger, and use Stinger for most of my boat installs. If you need anything from them, pm me.

http://www.stingerelectronics.com/search.aspx?delineateQuery=battery

[Brit Rider]

the_dude, 2 pairs of 0 guage wiring?! What amps are you planning on running?!

Most people like to mount the batteries fairly close then use something like this to link them:
http://www.talkaudio.co.uk/vbb/archive/index.php/t-54203.html
- all parts widely available for about 20 bucks in total.

You can then run 0 gauge wire (or smaller dependant on power needs) to a distribution block wherever you choose to mount the amps.

You really (if you haven't already) to work out how much power you're going to be using before deciding on wiring. Also, if it does turn out you need to be running to pairs of 0 gauge wiring - you're going to need a hell of a lot more than 2 batteries!

[Brit Rider]

This is a useful article if you have 20 mins, a doughnut and a large coffee to hand.
http://www.landyzone.co.uk/lz/f38/wiring-split-charge-relay-system-61268.html