I have an audio system that is taking too much power. I plan on installing a second battery in the back. how do I wire the battery in th front to connect to the battery in the back. I also plan on converting my alternator into a HO-140 amps with a smaller pulley. I read on older posts that the alternator might work too hard at higher RPMs , how do I solve this problem.
HOW MANY HORSES WILL THIS COST ME IF IM RUNNING A 350 ENGINE.

 

I think that post was from me.
You connect the positive post on one battery to the positive post on the other battery via a 1/0 welding cable with terminals crimped on each end. Do not wire them wrong.
You can either ground both to the engine block, or just the front one, and ground the rear to the frame. Be sure to grind down to bare metal where you bolt the ground cable to the frame & coat with silicone afterwards to protect from corrosion.
The grounds are the most important cables, so don't use 1/0 gauge on the power, and then only 4 gauge for the grounds.
Be sure to use a protective sleeve around the positive cable to prevent shorts. You normally do not want to run the cable through the interior of your car because of fire hazard with a short.

To get the most from your alternator use an external adjustable voltage regulator mounted in a cool place ahead of the battery/radiator. Use good quality copper wires of good size and route them away from heat.. shielding if necessary. Keep your alternator as cool as possible for more output. I have seen many many tricks to do this including cooling ducts from the front of the car to the rear of the alternator. It works.

Activate your voltage regulator (turns the alternator on) with a switched 12v source via an SPDT relay wired for contact in the normally closed positions. Use an RPM switch to activate the relay and kill the alternator at anything over your highway cruising speed (normally no more than 3000rpm).
Everything will be safe and work great.

without the alternator kill switch, the horsepower draw of the alternator depends entirely on charging load and has nothing to do with the engine size.
If your battery is fully charged and there is no electrical load, then there will be little hp loss.

ODB

 

or get a capacitor at least a farad. bass takes the most energy out of a charging system. a capacitor stores energy for dramatic peaks so it smoothes out the transition.

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formula,
I know what you're saying and caps have their uses, but for realworld performance in a car a battery is a much better storage device for power. Think about it, a cap, or a whole row of caps will not start your car. Two batteries act as a great voltage conditioner as well with no other circuitry needed.
IMO, most people that run caps for their stereo system actually need another battery.

 

What???????????? Somebody need to do some homework!!!!!

This (thirdgen.org) is a great site and I'm happy to have found it and learned a few things about cars (and hope to learn much more). If car audio is what you want to learn about - THIS IS THE WRONG SITE TO BE AT!!!

Here's some of my thoughts (I certainly not an expert at setting up dual batteries):

First, and most important, you HAVE TO FUSE the power wires with an inline fuse. Trust me. If you don't, sooner or later (Murphy's Law) you are guaranteed to burn your car down.

Second, the only thing a second battery is going to do is extend your playing time with the engine off. Nothing more. (Unless you're into serious SPL competition.)

Third, you should use a battery isolator when connecting up a second battery.

I highly recommend anyone with car audio questions go to the message board at www.carsound.com. The moderators are EXTREMELY knowledgable on the subject. I also recommend www.caraudioforum.com. It is less moderated so there is more bad information but the board is more active and there are many EXPERTS that give good, valuable info.

Note: I've been into "car audio performance" for quite some time and am just getting into "car performance". I've had my '91 Camaro for about a year and built a decent sound system in it. Now I'm trying to get some of the performance back that I lost by adding so much extra weight to the vehicle.

 

We DO have a Car Audio board here at thirdgen.org.

 

 

Ok. Sorry. No disrespect was intended towards the thirdgen.org "car audio" board. I've just be so excited since I found this site that I've been to busy trying to learn about suspension mods, engine mods, ect. that I haven't taken the time to check out the "car audio" part of the site. Anyway ... this a a great site, and thank you to the guys who made it happen.

 

welcome to the site.
I used to compete in car audio and do installs between 1988 and 1992 til IASCA started up and fubbed everything.
I am no longer into the audio so much or competing that way, but I'm still into 12v electronics. I enjoy racing more now anyway.
ODB


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*I do custom performance mods on Edlebrock Performer carburetors (dualplane intake mods in the works),
White 1986 Irocz, 305 with iron #416 heads,
383 with aluminum TFS heads,
Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, Vigilante 2400 lockup converter, 3.25:1 Ford 9" rear, Mcreary Road-Stars, SLP-stainless 1.75" shortie headers & Y-pipe, single 3" Borla exhaust, Linginfelter-TPI camshaft part number 74216 pulls 17" vacuum solid. Cam specs 213/219 @.050 114-LSA, sometimes advertised at 216/219 @.050 112-LSA .462/.470 lift @1.5:1 ratio. Using Harland Sharp 1.65:1 roller rockers. MSD-6AL, billet distributor, multi-retard, blaster-3 coil, and RPM switch. SouthSide machine subframe connectors, SSM lift-bars, Moroso 4" underdrive crank pulley.

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