Thread: best battery for under the hood?

If your going to buy an Optima, get a Yellow Top.

Redtops suck...and have been proven to fail...time and time again. Everyone around here has since replaced theirs with a factory ACD battery or a Yellow top...

Originally Posted by Fatboy501

2600 watts will pull more amperage than his alternator is going to produce, especially with it being stock. Voltage has stabilized greatly in many situations by getting a stout battery that is designed for quick discharges, which car audio requires. Do I have link to scientific evidence? Nope. However, I do know that running that much power on a stock battery and alternator will result in clipping and a dead amp or sub eventually, depending on how hard he pounds his equipment.

You really think so? Music is dynamic...we all agree. Ever wonder why people put heatsinks on a lead when soldering the wire to the speaker? Why do I need a heatsink for 30 watts of heat if the supposed speaker can handle 500 watts, etc?

You never see a continuous output of 2600 watts, ever, while playing music(unless your output signal and amplifier input stage aren't matched correctly). RMS. Why don't electrical engineers utilize this specification? BECAUSE IT DOESN'T EXIST! Why is it that RMS only exists in audio amplifiers? It's garbage, that's why. Smoke and mirrors/marketing.

From dictionary.com

rms the square root of the average of the squares of a set of numbers or quantities: the root mean square of 1, 2, and 4 is √[(1² + 2² + 4²)/3] = √7

So...the root of the average of squares? *forehead slap*

Originally Posted by Fatboy501

Voltage has stabilized greatly in many situations by getting a stout battery that is designed for quick discharges, which car audio requires.

Key words; "many situations". Did they involve a honda, grand prix, camaro...? Unless you can compare apples to apples then "many situations" doesn't fulfill our requirement of a 120amp alternator on a Pontiac Grand Prix. We have a world SPL finalist in our midst and he uses a stock alternator and burps(square wave/clipped signal) with a couple thousand watts.

I would presume his installation is very thorough and grounded properly.

So you've alluded to "quick discharges" as well. Does that mean the factory voltage is dropping below 12.6V? There's no way around that. If you aren't dipping below the charging voltage of the battery then there's no way it's supplementing the electrical system.

Do I have link to scientific evidence? Nope. However, I do know that running that much power on a stock battery and alternator will result in clipping and a dead amp or sub eventually, depending on how hard he pounds his equipment.

That's not how a power supply in your amplifier functions. Alternator voltage and RCA signal voltage are two different things. Just because the voltage in your electrical system dips doesn't mean your gain value on the amplifier changes.

The only power supplies that are regulated, meaning same output regardless of voltage, are JL audio amplifiers. Just because power output drops doesn't mean you clip a signal. That's a direct function of the gain and signal voltage.

Not necessarily... the phoenix gold Xenon amps used a regulated power supply as well, which was not a well-known fact. An amplifier attempting to pull power that just isn't available will result in serious voltage drop. Amplifiers have a protection circuit that kicks in at low voltages (varies between manufacturers) for a reason... it is not good for the amp, and will end up damaging it. A draw that serious on too low of a voltage will usually cause clipping in the signal, if the amplifier doesn't protect or go up in smoke first. You also stated that the individual burping with a couple of thousand watts is getting square waves AKA clipping. While that may not be a big deal during his short burps, supplying such a signal to a system used on a daily basis is not healthy for either the sub or the amp. Also, yes, it is possible not to drop below 12.6v on music... with an incredibly stout (expensive) electrical system. Also, while he will not see 2600 watts continuously, there will be spikes in the draw depending on the frequencies being played. I agree with what you say as far as burping is concerned. However, for a daily system above 1krms, a stout battery is needed in my opinion. I propose that we agree to disagree lol.

Originally Posted by Fatboy501

OP stated that -20 is a possibility during the winters in his area... I'd call that a tad bit outside of conventional.

You might.

Cold Cranking Amps (CCA at 0 deg.F)

http://www.sears.com/shc/s/p_10153_1...ype=G4#ppspecs

Battery capacity is reduced as temperatures go down. This is why your car battery dies on a cold winter morning. Capacity is increased at temperatures over 25 C (77 F), but battery life is shortened. Battery capacity is reduced by 50% at -22 degrees F. Battery life is reduced at higher temperatures - for every 15 degrees F over 75, battery life is cut in half, for ANY type of Lead-Acid battery, whether sealed, gelled, etc...

...but capacity is reduced at lower temperatures at the rate of 10% per 15 degrees F

About Batteries


I don't know that ~15% degradation in performance from zero degree specs will hurt your vehicle that much. What have people been doing all these years in Michigan?

Lol you tell me, I never plan on living in Michigan. However, -20 is still an extreme temperature in my book. I also had no clue that battery capacity was reduced in low temperatures... that's some crazy mess. While 15% degradation may not effect the average setup that much, that's not the case where a high-current audio system is involved. I still stand by my point that a nice AGM battery will be the best solution for his particular situation. I use AGM and Arkansas doesn't get anywhere near extreme temperatures. However, I saw a more stable after switching to AGM, and I'm only running approx. 1300rms total.

Originally Posted by Fatboy501

Not necessarily... the phoenix gold Xenon amps used a regulated power supply as well, which was not a well-known fact. An amplifier attempting to pull power that just isn't available will result in serious voltage drop. 1) Amplifiers have a protection circuit that kicks in at low voltages (varies between manufacturers) for a reason... it is not good for the amp, and will end up damaging it. 2) A draw that serious on too low of a voltage will usually cause clipping in the signal, if the amplifier doesn't protect or go up in smoke first. You also stated that 3) the individual burping with a couple of thousand watts is getting square waves AKA clipping. While that may not be a big deal during his short burps, supplying such a signal to a system used on a daily basis is not healthy for either the sub or the amp. Also, yes, it is possible not to drop below 12.6v on music... with an incredibly stout (expensive) electrical system. Also, while he will not see 2600 watts continuously, there will be spikes in the draw depending on the frequencies being played. I agree with what you say as far as burping is concerned. However, for a daily system above 1krms, a stout battery is needed in my opinion. I propose that we agree to disagree lol.

1) Um. That protection circuit must be below 11V? When you're vehicle is off the battery value can be ~11.8V. What is it down line? Again...I'd like to redirect you to the idea that if your engine is running then our 120amp alternator is sufficient.

2) A draw that serious? You were talking about "quickly discharging"...now "a draw that serious"? If the battery kicks in at 12.6V...and you're dropping below 11V...now you're exceeding the alternator and battery together? In what world/environment does that occur? I'd like to point out again....your amplifier will never approach 'rated' RMS, let alone "a draw that serious"

3) In a mathematical sense, a square wave(burp) and "clipped" signal are essentially the same.


You haven't addressed the issue at hand. I'm stating that the op's setup is well within the threshold of our 120amp alternators. In addition, if the engine is on...the battery will never supplement the vehicle's electrical system.

Ever seen a vehicle running without the battery?

lmao... yes I have. Are you suggesting that our alternators supply 120 amps continuously, even at idle? No, they do not. When the draw that serious... aka, a need for a quick discharge to satisfy a power-hungry amplifier, occurs if he is at idle, where oh where will that extra amperage come from? Also, yes, voltage does drop below 11v without a sufficient electrical system... if it never happened, and was impossible, as you imply, then there would be no need for the protection circuit concerning low voltage. If you've never heard of a system capable of causing a voltage drop to below 11v, I question how many large systems you have personally been involved with.I addressed the issue at hand perfectly: a stock battery and a 120amp alternator is not sufficient to run 2600 watts on a daily basis. If the OP does this, you can be the first to offer up every explanation in the world to why his equipment should not have failed when something goes wrong.

I propose that we agree to disagree lol.

Not a problem...but I like the healthy debates on topics like this so that others have a little bit more to go on besides the local opinion

Originally Posted by Fatboy501

lmao... yes I have. Are you suggesting that our alternators supply 120 amps continuously, even at idle? No, they do not. When the draw that serious... aka, a need for a quick discharge to satisfy a power-hungry amplifier, occurs if he is at idle, where oh where will that extra amperage come from? Also, yes, voltage does drop below 11v without a sufficient electrical system... if it never happened, and was impossible, as you imply, then there would be no need for the protection circuit concerning low voltage. If you've never heard of a system capable of causing a voltage drop to below 11v, I question how many large systems you have personally been involved with.I addressed the issue at hand perfectly: a stock battery and a 120amp alternator is not sufficient to run 2600 watts on a daily basis. If the OP does this, you can be the first to offer up every explanation in the world to why his equipment should not have failed when something goes wrong.

Not at all!! I was wondering when this would come up :>

But with that said, ever clamped to see the AVERAGE pull of an amplifer? An alternator can't keep up with a quick discharge? Now we're talking about the voltage regulator. A well built power supply on the amplifier should have the necessary capacitance built in. A battery is in no way comparable to a capacitor.

As far as 11V goes...I've been talking about the engine running this whole time. Not the engine off. That's why 11V isn't a valid issue at this point in time.

Ummm... voltage drops into the 11s do occur with the engine on. When that quick discharge is needed, and the car is at idle, with the alternator producing less than peak voltage, that power is pulled from the battery... a battery not suited to multiple fast cycles of charging and discharging will have a horrible time after this is repeated time and time again, which it certainly will be. After this discharge, part of the alternators power is re-charging the battery... what about when that next big bass hit occurs? Once again, a large draw is being placed upon the system. As far as a well-built amplifier power supply, the OP never actually stated what amplifier he is using... so well-built may or may not apply in his particular situation. Average pull of an amplifier differs greatly depending on the type of music one listens to. For instance, a rock song with lows around the 35hz range will not pull as much average as my decaf'd music with extended bass notes well down into the subsonic range.

Wking, what year is your gp?

Lol... so the battery has no effect at all on the audio system? I guess all of the competitors running multiple batteries and alternators are just wasting their time, when they could just have alternators alone. Lol... hilarious...

Love this site...

VOLTAGE

Fuses!!!
FUSES

Fuse Opening Time:
A fuse does not blow when the current reaches its rated current. It is designed to pass its rated current without opening. A fuse will take varying times to blow under different conditions. A fuse will pass significantly more than its rated current for a very short time. It may take 10 minutes or more to blow a fuse at 25% over its rated current. The table below is an example of the specifications for a slow blow fuse. You can see that a 20 amp fuse may pass 40 amps of current for as long as 5 minutes before blowing although it probably wouldn't take a full 5 minutes to blow. The times for other fuses will be slightly different.

Try running 40, 60, and 80 amp fuses in a similar system to the ops. Which fuses blow playing music at the loudest levels possible that doesn't damage or over stress the equipment. Please use the correct wiring as well!!!


EDIT: Question, what are some of those competition people doing to reach 150 decibels with a 6.5" sub? Are they the typical every day "competitor"? How are they doing it on just "500 watts"?

Originally Posted by Fatboy501

Lol... so the battery has no effect at all on the audio system? I guess all of the competitors running multiple batteries and alternators are just wasting their time, when they could just have alternators alone. Lol... hilarious...

You got that right!

There's a big difference between a bunch of consumers putting together a contest and real professionals.

Why doesn't home audio use batteries again? Only 20 amp outlets...?