Car stereo battery lots o $$$?

I just started getting into high power car audio and have a question for the experts, I am now pushing 600watts rms and plan on going more however i have the dreaded over tax headlight dimming issue. I have been told to get a expensive 2nd car audio battery such as the one from kinetic. My question is are these really something special or a re boxed version of a sports AGM.

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Please turn down the stereo ... and save yourself some money.

Headphones are a much cheaper alternative .


Besides .................. WE ..... don't wanna hear it .

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Just by a cheap battery to power the headlights and move on to mo power with mo money for the stereo!!

Back in the day I have seen quite a few car stereo enthusiast use expensive secondary batteries. But since then I have come to have my on opinion on the matter and learning here at cpf was a contributing factor. If you have a 2 year old oem battery in your car and you add a new high performance battery in parallel. Then what happens is the HP battery will do most of the work. It will be able to give more current and probably at a higher voltage. The Hp battery will always be helping the 2 year old oem battery keep up. When there in parallel its like having one big 12v battery with there capacities added up. The can also give twice the current if they where close to the same cca. In my opinion I would not worry so much about buying a HP battery and worry more about buying two matched batteries. Two brand new batteries in parallel of the same type, and make would act as one 12v battery with twice the capacity and twice the current capable output working together. They should also see the same life expectancy or close. I have a ford powerstroke that uses a dual 12v battery setup. When one battery die's and you replace only that one battery. The new battery will be short lived because its doing the majority of the work because the old battery is on its way out. Even when the old battery is at what most would consider dead or needs replacing you want know it because the new battery is taking up the slack, working it to death. Thats the reason ford replaces both batteries if one fails. I would just buy two new quality batteries that fit the car and run them in parallel with some heavy guage welding wire. Welding wire is quite flexible and can carry some high currents, it's what I use to use to wire my amps. It may be a good idea to buy a higher output alternator to keep up with the higher capacity parallel setup. I know from personal experience, my factory gm alternator died after about a year or less of use over working it. Just my two cents.

Have you tried using one of those huge 1 Farad megacaps inline with the power feeds to the Amp? You may have a 600w reserve but you are probably averaging around 10 watts most of the time and only pushing more power in the transient music peaks which require more power. A battery will give you more overall power at the cost of weight but that's not really what you need - you need help at the music peaks.

It basically follows the same concept in which caps are applied at the output of an AC - DC converter to smooth out the DC output and remove the AC ripple.

I don't know anything about this particular one (http://www.crutchfield.com/p_211ZN11FC/StreetWires-ZeroNoise1-Capacitor.html) but it's a good example to demonstrate what I am referring to.

Probably just as much $$$ up front, but probably less money wiring in the cap than a second battery.

Or, as a suppose what moderator007 was alluding to, just get a bigger higher CCA main battery to power your setup.

The op wants to stop the lights from dimming from the power surge that the amps* are creating. Even with a higher CCA battery, the lights will show the power surge by dimming, unless they are on their own power source.

I don't agree with you. A higher CCA battery will have a lower internal resistance and thus will exhibit less voltage drop under load. Basic electronic theory. Think IMR versus LiCO batteries.

Regardless, the CAP is a better first step solution.

The cap is better, and he's at 600watts rms and adding. What's the peak, 1200watts?

edit: What's the peak at 600w rms, 1200w? I don't believe there is a 12v battery or cap that can supply that kind of surge and keep the lights from dimming. In theory, maybe. Okay, that was a bad joke.

I already have a 1F cap and it helps but it is not enough. The amp i have is a Orion d1200 that will do 1200 peak but at least it is class d. I like the dual battery idea makes lots of sense. This is all in a 2000 S10 that has a stock 100amp alternator so that should be enough for now. Thanks for all the reply's guys!

Before you go investing in this, just borrow a friends battery and hook it up to your truck with jumper cables for the test. Turn on the system and crank it up.

Almost definitely a rebadged AGM battery from any number of AGM suppliers. Is it a sports AGM? Possibly, but not necessarily. Given the terminals from what I could see in the picture, I am thinking no. More likely a high rate AGM battery for UPS or renewable energy applications. Most of them have similar performance, but some are definitely better than others. Good ones are not cheap, but if you treat it well, it will last a long time.

I expect you will mount the supplemental battery right next to the amps? Given that situation, though it is effectively in parallel with the main battery, the wiring between the two batteries will be enough that the supplemental battery will have some level of isolation. High quality name brand batteries (and I don't mean Interstate here), will clearly indicate the internal resistance which you can use for comparing batteries.

Last, I hope you are only using that much power for competition? As has been pointed out, it's annoying to other drivers, pedestrians, etc. and in violation of the rules of CPF, likely illegal due to the excessively high noise levels that violate municipal codes. The other issue is it can and most definitely will wreck your hearing. It is not instantaneous ... the damage adds and you may not realize the damage done till you hit middle age and you notice it is hard to hear.

Semiman

Those batteries are way over priced, I agree that these are probably just re-badged AGMs. Check out the Odyssey line of batteries, they are highly regarded in some motorsports racing circles (http://www.odysseybatteries.com/).

thekobk said:

I just started getting into high power car audio and have a question for the experts, I am now pushing 600watts rms and plan on going more however i have the dreaded over tax headlight dimming issue. I have been told to get a expensive 2nd car audio battery such as the one from kinetic. My question is are these really something special or a re boxed version of a sports AGM.

Click to expand...

I have designed and installed many award winning car audio systems & can give you a few hints .

You have stock headlights & wiring ? Check & clean all connections .Your car's electrical system was never designed for such a massive additional amperage draw .


Has the battery in the car ever gone so low as not to start the car ? Replace it .With a larger capacity one . Then replace the alternator with a high output unit .

I suspect you have big wires from the oem battery to your amps of the correct wire gauge, yes ?
Add an additional massive wire from your negative terminal to the chassis of the vehicle . To bare shiny metal . With soldered terminal's & bolted down as short as possible .

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The audio system bass & transient response will benefit from adding a large capacitor as close to the amps as possible . The only reason to add an additional battery is if you run the system without the engine running .
A dual battery system consists of 2 NEW IDENTICAL batteries ( sound familiar ?) & a Dba or isolator relay .

I personally would not spring for any "fancy " or "Competition" batteries . Snake oil . Snake oil. Snake oil .

Have fun & protect your hearing .

.

As BudK said, check all terminal/connections are clean and good large contact areas with large gauge cabling and fit a high output alternator. Generally you should not be running that much power output on battery power alone, it will not last long.

When I was doing high power installs to my own car, a fresh and full charged standard battery lasted 10mins or less, meaning you really must keep the engine running and have a decent alternator.

I also used to run with a second (and third) battery identical to the one fitted under the bonnet in the boot of the car so the wiring to the amp was kept very short and very large gauge. The battery was in parallel to the main battery and a 1 Farad capacitor fitted in parallel which helped tighten up the bass. If you are running very high output then you can add more capacitors. I always used good quality standard car batteries, not any fancy or more expensive gel types. as a simple guide, the cheaper 12v batteries usually have a 3 year guarantee, but the better ones have a 5year, or more, warranty I found these worked well.

Good luck, and now you have me hankering for some eyeball shaking bass - Headphones don't 'move' you like real bass does

subwoofer said:

As BudK said, check all terminal/connections are clean and good large contact areas with large gauge cabling and fit a high output alternator. Generally you should not be running that much power output on battery power alone, it will not last long.

When I was doing high power installs to my own car, a fresh and full charged standard battery lasted 10mins or less, meaning you really must keep the engine running and have a decent alternator.

I also used to run with a second (and third) battery identical to the one fitted under the bonnet in the boot of the car so the wiring to the amp was kept very short and very large gauge. The battery was in parallel to the main battery and a 1 Farad capacitor fitted in parallel which helped tighten up the bass. If you are running very high output then you can add more capacitors. I always used good quality standard car batteries, not any fancy or more expensive gel types. as a simple guide, the cheaper 12v batteries usually have a 3 year guarantee, but the better ones have a 5year, or more, warranty I found these worked well.

Good luck, and now you have me hankering for some eyeball shaking bass - Headphones don't 'move' you like real bass does

Click to expand...

Don't use GEL batteries, they have poor resistance compared to AGM batteries. The Odyssey batteries are considered good batteries, but there are different types.

Looking at the Kinetic batteries, I would say if they really are high quality batteries, then you should be looking at 60-65% of their MSRP as a retail price. Good quality AGM batteries are no inexpensive.

The big caps do work, but they generally do not have enough storage to prevent lights from dimming.


Semiman

I read through this thread yesterday and as I have no experience with high output car stereo, I didn't comment. As a mechanic though (mostly aircraft, but......) I have to agree that a higher output alternator is the solution.

In a car, the battery's primary purpose is to start the engine. From that point on, it is the alternator's responsibility to provide all necessary power requirements (and of course, recharge the battery).

It would seem to me that the only time an additional battery, or one with a higher capacity would be needed, is if the stereo is used without the engine running. No matter how you go about it, this is gong to kill any lead acid battery(ies). They are not meant to be discharged to any significant degree, and at that, should be charged up as soon as possible. Using a deep cycle marine or AGM battery, will work better for this, but even these types of Pb batteries will not last long if deeply discharged frequently.

Dave

Shame on you guys for not mentioning the big 3. BudK touched on one however.

A '12v' system runs at ~14-14.5v when the alternator is powering things. When a SLA is under load its output voltage will be 12.5-13.0V or so when its full (depending on load, internal resistance etc) All energy that your stereo uses comes from the alternator, full stop. When the alternators output cant keep up and battery provide current, the voltage will fall to the 12.5-13.0v or so that the batteries provide. An incan filament with its supply dropping from 14v to 12.5v will be noticeably dimmer. So no matter how many batteries and caps you add, you will still have the same problem.

The 'Big 3' improves your charging system by giving it a better path to the battery, so that it can help keep up with the stereo.

For the positive side, a heavy wire from the alternator output to the battery + terminal lowers the resistance of that, simple enough.

For the negative side, a heavy wire from battery - to chassis loweres the resistance of that, simple enough also.
Also for the negative side, you need better bonding between your alternator and the chassis. Your alternator is bolted to your engine block which is mounted on rubber mounts, and has a ground strap of unknown size and condition (how corroded is it?) to go between the block and the chassis. Get a heavy braided ground strap (you need the flexibility, even welding cable could have issues with all the vibration of an engine on mounts!) and install it from chassis to engine block (or alternator frame if there is any good looking bolts/lugs available)

A 1F cap with a 750W load (600W class D amp, allowing for efficiency, etc...) will drop from 14.5v to 10V in .066 seconds, obviously they are going to do nothing to help with dimming headlights. However, if the input voltage doesnt change as rapidly, it can allow the SMPS internal to the amp to maintain proper regulation better (I.e. it only has a current transient, to deal with, and not an input voltage drop transient also) so improving how tight/clean the bass sounds is plausible, not here to argue about that.

I would address the headlight issue in the following order:
1) Big 3
2) Check additional grounding. (where do the headlights ground? if its somewhere a lot of current flows when the amps draw a lot of power, perhaps your ground isnt good enough for them. Its called 'ground bounce' on a PCB, not sure what its called in the automotive realm)
3) Battery in trunk with hefty leads to the amp. If the voltage sags over the long run to the main batt, then the trunk battery will still provide the needed current. Without the trunk battery, the amp has to draw more current to get the same wattage, making the situation even worse. (in a severe example, if the amp is recieving 10V on a bass hit requiring 500W to be drawn, then 50A will be drawn. Vs 14.5V requiring only 35A. A trunk battery would limit the voltage sag to 12.5-13.0V during the transient, and the current drawn from the front to the rear will be smoothed some, so it would be a more constant draw, rather than a jump from low to high to low.

4) high output alternator Probably not needed for a 600W system, but it would be the next step.
5) Moar batteries, moar wire, moar alternators

Thanks for the detailed explanation. I was trying to figure out to explain that even with extra power, a voltage drop will still dim the lights, but couldn't.

On the AGM batteries, high quality ones can be discharged completely 200+ times as long as you recharge them soon after. They can take 80% discharge 500+ times and 50% discharge 1000+ times.

That said, when the car is on, it is alternator sag you need to deal with and that alternator has a transient response on its own measured in 100s of milliseconds and then the mechanical issue of the engine supplying more power comes into play as well depending on the engine RPM.

Even at full blast, the average power draw of your amps is not very high, maybe 100-150 watts. It you wanted a fool proof system, you could run the amps off a secondary battery with that secondary battery served by an "isolated" charging circuit. Isolated would not need to be very complicated and would prevent the headlight dimming issue. You could probably get by with a reasonably sized secondary battery, perhaps 50AH as long as it is a high discharge rate high quality AGM battery.

Semiman