New member with wiring question

[tdyltc46]

Hello everyone,

This is my first post on your forum. I have an AM-FM radio/cassette player wired in the traditional manner (wired so that the power to the player is controlled by the ignition. I am thinking about placing a battery in the trunk and running a hot wire and a ground wire to it so that I can turn the ignition off and power the player off of the battery in the trunk. This would prevent the car battery from being drained while playing the cassette player at car shows. My question is this: Will this set up have any negative effects on the vehicle wiring?

 

[woodsnake]

It won't hurt anything as long as you keep everything seperate. There are probably a few better ways to do it.
How long do you plan on running the radio with out starting the car?
I haven't seen a lot of guys that leave a radio on, it kind of distracts from everything else that's going on.

Where are you TDY at?

 

[Tim65GT]

I have done this - not on my Mustang, but on a couple other vehicles. You will need to wire in a charge relay. It energizes with the ignition circuit and charges the battery while running, but when the key is off, it will deenergize and isolate the Aux battery from the Main battery.

I would recommend a deep cycle marine battery and use grommets to protect all wiring that goes through the trunk floor. Here is a diagram:

 

[tdyltc46]

Thanks guys,

I appreciate the replys. I am currently located in Freeport, Illinois. I am retired and my wife and I Spend 6 to 8 months of the year in Comfort, Tx. (near San Antonio) in our motorhome.

 

[suki243]

Sorry don't mean to hijack the thread, but is there a way to power it with aux key position? Also, what is the aux key position for?

 

[Tim65GT]

You mean ACC (Accessory) The radio is already powered by the acc key position. It also send power out to any accessory that is wired to the center pin on the back of the ign switch. I think wipers are tied to it too.

 

[aug0202]

use heavy duty metal straps. you don't want that thing moving around at all
use no lighter than 2 gauge cable running from your engine (alternator or battery) to the trunk. And ~1.5ft of 2 gauge ground cable to connect to the car chassis.
remember to get the terminals for the extra battery to connect to your amp. These will allow you to connect ring terminals:
http://www.hardwarestore.com/media/product/130245_front200.jpg
these would allow the wire to connect without ring terminals
https://www.addison-electronique.com/catalog/images/030105.jpg
It's a good idea to have a separate battery if you're listening to it with your engine off. Use a battery isolator too (essentially a high current relay) so your main battery won't get drained. You won't want a regular car battery, use a kinetic or optima yellow top. A regular one won't last very long after getting drained many times.

 

[tdyltc46]

Thanks again for all of the great replys. I ordered and received my 75 amp charger/battery isolator relay and am about to install it and the battery. I have a couple of more questions. I am rethinking placing the battery in the trunk. I have been told that when a battery recharges it puts off a gas and needs to be in a ventilated space. Has anyone ever placed a second battery in the engine compartment, if so, where and how? I have a 66 six cyl. so there is some available space. It would also take considerably less wire. Also, one of the terminals on the relay is marked "ignition". Which ignition wire do I attach there?

 

[Tim65GT]

I have been told that when a battery recharges it puts off a gas and needs to be in a ventilated space.

True, mine is in a sealed battery box with a vent tube going through the trunk floor. It still requires regular maintenance like a lead-acid battery in the engine compartment. You could get an Optima type battery. They do not have the caustic liquid sulfuric acid.

Has anyone ever placed a second battery in the engine compartment, if so, where and how?

Most people here move the battery to the trunk for more room and better handling. Both dual battery set-ups I did before were in trucks.

 

[tdyltc46]

Thanks Tim65GT, That gives me an idea, I will let you know how it turns out.