Would it be possible to just throw another battery in the trunk to power my audio equipment? Are there any downsides to doing this? Where would I attach the negative terminal?

 

I am by no means an expert, but wouldn't a battery in the trunk be a bad idea since it would never get charged by the motor?

 

A battery in the trunk is no problem at all. For starters, just make sure you secure it well so it doesn't slide around. There are a few ways to do it, the easiest being this:

-Run at least a 4 guage wire from the engine bay to the trunk.
-Connect this wire to the positive terminal on the battery in the engine bay via a battery relay, and connect the other end of it to the trunk batteries positive terminal.
-Ground the battery in the trunk to the chassis of the car....make sure this connection is nice and tight, and free of paint (bare metal)
-The battery relay will require an ignition wire be attached to it so it only energizes and charges the trunk battery with the car running...when the car is off, it will de-energize, and disconnect itself from the engine compartment battery to prevent drainage.....

You can do it like that, or do it where you connect the alternator through a battery isolator and then each battery gets connected to seperate terminals on the isolator.

 

LMAO.

You have correctly described this installation... but you have glossed over a few things.

1) Dual-battery systems can be very problematic regarding noise. Very.

2) Battery isolators are a huge PITA. For one thing, they are huge diode bridges, and as such they insert a voltage drop that prevents full alternator voltage from reaching either battery.

For this reason, the battery relay is better... but you don't have much room to install one anywhere in the engine compartment in most Acuras...

3) To charge both batteries, you'll probably need to upgrade your alternator - which will probably solve your original problem, and if it doesn't, you probably didn't really need a second battery anyway.

 

Just wanted to give him the basics....and I do this all day long professionally and I've NEVER had a problem with noise, charging two batteries with the stock TL/CL alternator or anything of the kind, and have never had any problems with fitment under the hood of the necessary equipment.

Oh, and yes, you are correct about the relay being the way to go....it's the only thing I use

 

Good, that makes two pros on this thread. We started adding second batteries at my shop back in 1987. It can be problematic, and we still haven't discussed safe venting. I would not agree that saying dual-battery installation is "no problem at all" is accurate.

Ron, why are you adding second batteries? What amp-draw situation is prompting you to do that? (And how often do you do it?)

If you are killing the main battery, you need more amps, right?. If you're not, then maybe you just are adding them for parking-lot use?

I would say that adding a second battery and installing a significant amplifier load into an Acura vehicle with the stock OEM alternator, would shorten the life of the OEM alternator.

 

i wanna add a second battery but is it just better to have a really upgraded alt. and a nice battery instead of two?

 

Yungin, I would say so.
Thats what I'm gonna do-- red top and a substantially larger alt.

Oooooh, I finally got my Xtant amp back... its sooooo f'ckin BAD-ASS.
If i dont change the oem alt soon, its gonna be toast sooner or later.

 

If you are interested, we make great deep cycle batteries www.trojanbattery.com Not pretty, but they get the job done better then the rest.

 

When people ask me to add them, I add them. Usually they are for show use where they run their systems for an extended period of time and are using some kind of power supply and don't want to draw off the cranking battery. For the most part they are deep cycle optima's or something of the sort....mostly the Schoshe batteries actually, so venting isn't an issue.

But regardless, I say "no problem at all", because to me, they aren't To each his own, we all have are own opinions

 

First off, I like to go yellow-top Optima. Had one for a long time in my last car, have one in the CR-V, probably drop one in the TSX soon.

Then upgrade the charging cable from the alternator to the battery, and the ground cable from the battery to ground. This can make a huge diff in measured voltage in the trunk at the amps...

Then consider an upgraded alternator if you have a draw issue - that is, if you have enough amplification drawing enough amperes to give you issues.

All the extra battery gets you is the ability to play for longer periods without the engine/alternator running.

Always keep in mind that when a car is running the batteries become loads that take power away from your amps. The advantage of secondary batteries is that when the car is off, you can listen to your stereo for longer periods of time.

Adding more batteries will not make your stereo perform any better when the car is running. In fact, a second battery will steal power from the electrical system when the car is running.

http://www.carstereo.com/help/elect_upgrade.cfm

 

Agreed!