How to add a second battery

[ej20fan]

Originally posted by tad_02Wgn
the electrical system of a competition vehicle is quite different from that of a daily driver... try charging a trunk full of batteries on a stock alternator.

Although I do agree with you on getting the charging system tested.

True, we use powersupplies to drive and charge these systems, though many of the vehicles we compete in are still daily drivers. Regardless, the alternator is tested with a multi-meter. Very easy.

The alternator upgrade is really not that necessary. I'm running a pretty big system, RF 5002 and RF4004, with Kove Opulent Components in the front and matching 4" rear, with a T3 sub in a custom box. I have had no problems.

The most important thing to remember when it comes to soundsystems is proper installation. Bad install's make up for more than 90% of the problems we fix at my shop.

[tad_02Wgn]

Originally posted by ej20fan
True, we use powersupplies to drive and charge these systems, though many of the vehicles we compete in are still daily drivers. Regardless, the alternator is tested with a multi-meter. Very easy.

The alternator upgrade is really not that necessary. I'm running a pretty big system, RF 5002 and RF4004, with Kove Opulent Components in the front and matching 4" rear, with a T3 sub in a custom box. I have had no problems.

The most important thing to remember when it comes to soundsystems is proper installation. Bad install's make up for more than 90% of the problems we fix at my shop.

I certainly agree with you about the bad installs - most of the dimming problems that I have encountered were usually just the case of a poor ground.

Really when it comes down to it - extra batteries are good for two things.
1.) Extended play-time when the car is off
2.) Providing the extra current necessary for shorter periods of time, much like the reasoning for adding a capacitor.

So... if you're only going to be burping your system, or if your system doesn't draw more current than your alternator - car draw, you're all set.

However, if you are consistently running enough electronics that you are drawing, say, 50A worth of accessories from a 75A alternator... there's no way to get around an upgrade.

It's certainly not somethign to jump into though - it's a big step. Ultimately, however, it is the proper solution to the power problem, instead of just a band-aid type solution like a cap (or battery in some cases).

Not trying to start an argument - I think we're both right and making good points. Situations like this really must be evaluated on a case-by-cases basis.

For example, I ran a 1500W+ RMS system (two ARC Audio amplifiers) in my jetta with the stock 90A alternator without any problems whatsoever.

[ej20fan]

Which Arc's, KAR or XXK. I'm a dealer and those amps kick. Love them. I'd compare them to the old PPI's.

Anyway, true that on your advice. I like that this thread is actually covering important ground and giving sound advice rather than turn into a pissing match.

I honestly don't believe that you should need either extra battery or alternator, as I'm doing fine. I have upgraded my front battery to a Optima yellow top though, but other than that, I've had no problems, nor required the need to upgrade any other electrical component of my car.

Check your install again, and you will most likely find the culprit.

[tad_02Wgn]

Originally posted by ej20fan
Which Arc's, KAR or XXK. I'm a dealer and those amps kick. Love them. I'd compare them to the old PPI's.

Anyway, true that on your advice. I like that this thread is actually covering important ground and giving sound advice rather than turn into a pissing match.

I honestly don't believe that you should need either extra battery or alternator, as I'm doing fine. I have upgraded my front battery to a Optima yellow top though, but other than that, I've had no problems, nor required the need to upgrade any other electrical component of my car.

Check your install again, and you will most likely find the culprit.

agreed,
I had an arx cxl 4150 and cxcl 1500.. powering focal 165k2 comp set and ed 12a. It was such a nice setup, but i needed money for school and a new car. killer equipment, just way tooo costly.

[ej20fan]

NICE!!!

[scooby_93]

I'm running two Optima Yellow Tops just now - one for the car and one for the sounds. I've used what we call a split charger - they tend to be used on caravans, where there are two batteries one in the car and one in the caravan. Both batteries can be charged automatically, or if you install a switch, then you can choose when you want the back battery charged. I've got mine running automatically. I've also got a 1.5 Farad Capacitor and a Fused Distribution Block. The split charger is basically a relay installed close to the car battery, and then running to the back battery, with a fuse and an ignition feed in between.

John

[hamz01]

How do you run two batteries but have one dedicated only to the audio system? What would happen if I just got a second battery and wired it in parallel with my current battery?

Thanks

[scooby_93]

I'll try and explain how I've got the two batteries rigged up. Here goes:

First, I have a relay situated near the battery under the hood. From the relay, I have a 60amp fused live wire going into the positive terminal of the battery under the hood. On the other relay terminal, there is another live wire going from here to the positive terminal of the second (auxilliary) battery, which is situated in the back of the car. This wire also requires to have a 60amp fuse near the aux battery. Again, from the positive terminal of the aux battery I have another live feed from it going into a 1.5 Farad Capacitor, which then comes out and continues onto a one-in-two-out fused distribution block and then goes into the positive on the amp.

Going back to the aux battery, the negative terminal just goes to chassis earth. The negative terminal of the Capacitor also goes to chassis earth, as does the negative on the amp.

Going back to the relay (remember there are four pins on the relay), you have an negative which can go to chassis earth or the negative terminal on the first/main battery and then there is also a switched ignition feed required.

I know this sounds really complicated, but honestly it's not. If you want, I can send you a diagram which will be a hell of a lot easier to understand.

The way this is wired, as soon as you start the car up, both batteries will charge.

John

[hamz01]

Thanks a ton! That was a great discription.. I was able to follow it. So basically, with your wiring configuration, the only thing I'd need to worry about is whether or not my alternator would be able to handle the extra load of another battery (and I don't really know how to determine this or what the factors are). Thanks again for the reply!

[scooby_93]

No probs. Glad you were able to understand it.

Not too sure about the alternator - I've just got the original in mine. I would assume that the standard one should cope OK. I've never had to change my alternator in any of my cars and I've always run two batteries - and nothing's blown up or melted - yet!!!

John

[hamz01]

[Geekqualizer]

I would add to some of the above excellent suggestions that the grounding mod for your application is probably a good idea as well.

[hamz01]

What's the grounding mod?

[Geekqualizer]

The grounding mod enables your vehicle's electronics to 'talk and listen' to themselves with more accuracy. This allegedly results in a couple of extra HP and a smoother idle. Also, the headlight dimming issue at idle disappears.

My personal experience with the grounding mod agrees pretty much with the above claims (though my butt dyno can not confirm the small HP gain).

This mod is not hype or vodoo; it really works!

[hamz01]

Sounds excellent... but what, specifically, is it? What exactly does the grounding mod consist of; is this the "big-3 upgrade"?

More hp and less headlight dim sounds real good