multiple batteries vs. high output alternators

[audiolife 5,000+ posts]

so your system stays at 14.5 while turned all the way up?

 

[iceteebone 5,000+ posts]

so your system stays at 14.5 while turned all the way up?

yes. it does at times fluccuate between 14.4 and 14.5 but i'm not gonna ***** about it

 

[audiolife 5,000+ posts]

so you have like a 220 amp alt on a 500 watt system?//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[iceteebone 5,000+ posts]

so you have like a 220 amp alt on a 500 watt system?//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

250 amp alt on around a 2000 watt system. and i even use cheap welding supply wire to boot //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[audiolife 5,000+ posts]

generally speaking a 250 amp alt will do 250 amps at 12.8v

 

[Thnking 10+ year member]

What are the pros and cons of using multiple batteries vs a high output alternator in a High wattage system?

A high output alternator has a higher nominal voltage than multiple batteries have.

Energy is also created by a mechanical to electrical conversion, which means the engine is suffering the energy loss (which is insignificant to the engine, and not related to the electrical circuit efficiency). A battery suffers from energy loss during recharge/discharge, so it increases the amount of energy needed to maintain a current and voltage level (the electrical circuit efficiency is decreased). This is compounded by adding more batteries.

Batteries have a 2+V lower voltage than an alternator is regulated at. Meaning they are constantly being recharged, energy is constantly being lost.

The only time I would add multiple batteries is when someone is competing or listen to music when the car is off. Competition uses very high short duration loads, and listening to music when the car is off requires a lot of stored energy.

Most people find simply a H/O alternator is sufficient.

 

[mlstrass 5,000+ posts]

Most people find simply a H/O alternator is sufficient.

I'm running around 2200 watts, did BIG 3 in 1/0, added an SVR under the hood and 200a HO alt and still had bad dimming issues.

Last weekend I added a Deka Intimidator in the trunk and dimming is gone and subs hit harder as I'm not seeing the huge voltage drops.

What I still don't understand is the how/why adding a 2nd battery fixed my problem as I've read time and time again that when a car is running it's being powered by the alt, which makes sense. Happy but confused...

 

[helotaxi 5,000+ posts]

The alt needs a buffer, plain and simple. A hydraulic system has an accumulator, an air compressor has the air tank, your alt has the battery.

 

[Thnking 10+ year member]

I'm running around 2200 watts, did BIG 3 in 1/0, added an SVR under the hood and 200a HO alt and still had bad dimming issues.
Last weekend I added a Deka Intimidator in the trunk and dimming is gone and subs hit harder as I'm not seeing the huge voltage drops.

What I still don't understand is the how/why adding a 2nd battery fixed my problem as I've read time and time again that when a car is running it's being powered by the alt, which makes sense. Happy but confused...

There are too many variables to answer your question.

I'd probably guess that resistance @ grounding points were too high or your alternator wasn't calibrated to discharge @ the given RPM's for your needed load.

If you're talking 2200watts in RMS rating of the amplifiers, I've ran upwards of 3000watts RMS ratings with a 180A alternator 1 stock size battery with no dimming and voltage drops under .5V. My point being that electrical setup and actual levels are a huge factor.

Reading the 100's of posts on various forums leads me to believe, people don't understand how to properly ground / select a H/O alternator / and select wire sizes. So I'm not surprised that when someone is getting 3+Vdrops and they add another battery they are only getting 2+ Vdrops. It's not backing up any additional battery statements, only pointing to the obvious fact that adding another battery adds more energy availability under 12V.

 

[audiolife 5,000+ posts]

There are too many variables to answer your question.
I'd probably guess that resistance @ grounding points were too high or your alternator wasn't calibrated to discharge @ the given RPM's for your needed load.

If you're talking 2200watts in RMS rating of the amplifiers, I've ran upwards of 3000watts RMS ratings with a 180A alternator 1 stock size battery with no dimming and voltage drops under .5V. My point being that electrical setup and actual levels are a huge factor.

Reading the 100's of posts on various forums leads me to believe, people don't understand how to properly ground / select a H/O alternator / and select wire sizes. So I'm not surprised that when someone is getting 3+Vdrops and they add another battery they are only getting 2+ Vdrops. It's not backing up any additional battery statements, only pointing to the obvious fact that adding another battery adds more energy availability under 12V.

then you arent doing the power you say you are...when they rate alts 180 amp - to 300 amps they do it DOWN to 12.8v meaning that is generaly the voltage drop at full rateing

 

[Boulderguy 10+ year member]

Let's talk comman sense tho, it's all about what you expect from your system.

If you crank it full tilt for long periods of time you'll drain even multiple batteries w/o a better alt.

If you just bump occasionally for short periods you're probably fine with just the batteries, or even a single good battery.

If you compete - multiple batteries are the way to go.

If you have high-draw accessories in the car & keep a large system at moderate volumes, go with a single battery & the HO alt.

If you have very large amps even short 1-2 song blasts can drop your voltage enough to send the electronics into protect w/o the HO alt.

My vote: HO alt & a single good battery unless your system requires something different.

 

[audiolife 5,000+ posts]

talk common sense you do realize that if you are really getting the high output alt to drop to 12.5-12.8 v that somewhere along the line until the charging system catches up its going to be below 12.8. people will say this doesnt happen because they "test " with their dmm. thing is a digital dmm without the right setting avalible on it reacts VERY slow (this is where analog would show that the voltage is actually moving all over) the load is constantly changing so the output does too. i am talking miliseconds covering peaks. if you were to graph the alt out put it would look alot more like a moutain range than any type of a clock signal in real time.

 

[mlstrass 5,000+ posts]

There are too many variables to answer your question.
I'd probably guess that resistance @ grounding points were too high or your alternator wasn't calibrated to discharge @ the given RPM's for your needed load.

If you're talking 2200watts in RMS rating of the amplifiers, I've ran upwards of 3000watts RMS ratings with a 180A alternator 1 stock size battery with no dimming and voltage drops under .5V. My point being that electrical setup and actual levels are a huge factor.

Reading the 100's of posts on various forums leads me to believe, people don't understand how to properly ground / select a H/O alternator / and select wire sizes. So I'm not surprised that when someone is getting 3+Vdrops and they add another battery they are only getting 2+ Vdrops. It's not backing up any additional battery statements, only pointing to the obvious fact that adding another battery adds more energy availability under 12V.

Battery up front is grounded to factory point on the block with 1/0. Rear battery is grounded to bolt that holds body to the frame. That's where the sub amp was originally grounded, now it's going to the rear battery.

System is 2200+ RMS. 200a was the biggest stock case offered for my car. Don't believe it was a ground issue, just too much demand on what I had, but the 2nd battery has taken care of that....

 

[da12b 10+ year member]

I say to plan out your system either 1 or 2 batteries. There are pros and cons to just about averything you do. The pro is that you will be able to "pound" you system with your car off without killing your main battery, providing you have an battery isolator. The con is that you will have to rewire your system. There are a lot more pros and cons to this subject, but this is the immediate use for it I can think of without being technical.

Check out http://www.bcae1.com/

I use this site a lot for reference.

 

[Thnking 10+ year member]

then you arent doing the power you say you are...when they rate alts 180 amp - to 300 amps they do it DOWN to 12.8v meaning that is generaly the voltage drop at full rateing

And that's my point.

While my amps are rated for 3,000watts RMS, my system isn't creating that large of a load.