Tell me again why I need more battery reserve ???

[Fish Chris]

Okay, so in my system, I'm running two amps, with a total fuse rating of 340 amps. So I figure I'm probably never drawing more than about 170-200 amps. My alternator puts out 320 amps (but everyone argues about this) so lets say 200 amps to be safe. What do I need more reserve for ? Wouldn't a freaking motorcycle battery be enough ? Granted, I still need enough CCA's to turn the motor over, but why do I need another battery for the stereo system ?

 

Yes, I am going to be adding a 500 farad super capacitor bank soon, to make faster bursts of power, for better dynamic range of my system. But that will have nothing to do with storage. That is simply to make faster delivery of power when needed.

 

Honestly, I think if I ever go to more, or larger amps, Id be considering more, or larger alternators at the same time. I think if my system used 1000 amps continuous, Id want enough and strong enough alts to make 1200 amps continuous.

 

Your thoughts ?

[1point21gigawatts]

Reserve is only for if the current draw exceeds the alternator’s capabilities or if the vehicle isn’t running and the alternator isn’t on. 

[CstrokerV]

2 hours ago, 1point21gigawatts said:

Reserve is only for if the current draw exceeds the alternator’s capabilities or if the vehicle isn’t running and the alternator isn’t on. 

It also puts a buffer between the alt and amp...reserves do more than what you put... why do you think people who’s still have alts that can produce the amps they need still have a battery reserves or a cap bank 

[1point21gigawatts]

3 hours ago, CstrokerV said:

It also puts a buffer between the alt and amp...reserves do more than what you put... why do you think people who’s still have alts that can produce the amps they need still have a battery reserves or a cap bank 

They use extra batteries and caps to keep their voltage up if they already have enough current draw to feed the amps. Since you know so much about the matter, elaborate on what reserve is used for instead of being vague and saying I’m wrong by saying there is more that reserve is for. All you said was a secondary battery is used as a buffer. Explain the whole buffering process and what I left out on what reserve is used for. 

[1point21gigawatts]

6 hours ago, Fish Chris said:

Okay, so in my system, I'm running two amps, with a total fuse rating of 340 amps. So I figure I'm probably never drawing more than about 170-200 amps. My alternator puts out 320 amps (but everyone argues about this) so lets say 200 amps to be safe. What do I need more reserve for ? Wouldn't a freaking motorcycle battery be enough ? Granted, I still need enough CCA's to turn the motor over, but why do I need another battery for the stereo system ?

 

Yes, I am going to be adding a 500 farad super capacitor bank soon, to make faster bursts of power, for better dynamic range of my system. But that will have nothing to do with storage. That is simply to make faster delivery of power when needed.

 

Honestly, I think if I ever go to more, or larger amps, Id be considering more, or larger alternators at the same time. I think if my system used 1000 amps continuous, Id want enough and strong enough alts to make 1200 amps continuous.

 

Your thoughts ?

I forgot to say that secondary batteries also help keep the voltage up. And I didn’t even read where you said anything about caps. Caps help the voltage more so because they have a quick charge and discharge rate. So with caps even if you have enough reserve, caps help the voltage a lot because of the quick charge and discharge rate. But you already know that. 

[fishchris1]

2 hours ago, 1point21gigawatts said:

I forgot to say that secondary batteries also help keep the voltage up. And I didn’t even read where you said anything about caps. Caps help the voltage more so because they have a quick charge and discharge rate. So with caps even if you have enough reserve, caps help the voltage a lot because of the quick charge and discharge rate. But you already know that. 

Hey Gig, your response is totally what my research tells me. Yet over and over, I read people saying... More batteries, more batteries.... Instead of more /stronger alternators ? 

 

I think it would work fine (and screw with a lot of guys heads too) to have like a 20Kwt system, and yet making 1500+ amps continuous (with like four 390's) And then running a single battery, and a nice bank of caps.... Like 3000 farads. Sure would save a lot of weight.

 

Hmmmm. Just not into a whole bunch of heavy batteries. I would rather just make enough juice right from the get go.

 

Btw, I even have an idea (which I have never seen done) but of which I am 1000% confident would work, to make 2000 amps, heck 4000 amps continuous. This would be great for 30 or 40Kwt show systems..... And wouldn't need shit for batteries.

[audiofanaticz]

Plot twist:
Your alternators wont always put out full current....
Alts will only achieve their full output typically at 2000-2300ish engine rpm, your engine never be continuously at that unless your parked with an idle lock of some sort or your foot on the gas.

Another problem is when the alts get hot, they put out less amperage.

Another problem is these alts that do crazy high output like this do crap output at engine idle.

Ask me how I know... 

Because I have 3 390XP amp alternators that should produce 1170 amps of current, yet with 9 runs of positive and 9 runs of negative from alts to rear batteries, frame grounds front and rear.

Also had 2 XS Power S3400s under the hood, and 5 d3100s in the back. 

With 2 Sundown SAZ-4500s wire down at .35 ohms I had massive voltage drop down into the 11.2 volt range.

The thing with alternators is they wont make the power until they see a demand for it, so the  beat will drop and a couple seconds later your alternators yell at each other saying to wake up and get to work.

The thing with music is its not a constant sign wave, there is breaks in the beat and in those times your alts will then start to put out less current.

 

Reserve is needed no matter what.

All I changed in my truck is going from 7 XS Power batteries and 3 390XP alts to a 95ah CMAX bank and no agm with only have 1 of my 390XP alts hooked up at the moment and my voltage sits at 15.3 and never drops below 14.9 full tilt where as it use to be 11.3 volts with 3 alts.

[fishchris1]

3 hours ago, audiofanaticz said:

Plot twist:
Your alternators wont always put out full current....
Alts will only achieve their full output typically at 2000-2300ish engine rpm, your engine never be continuously at that unless your parked with an idle lock of some sort or your foot on the gas.

Another problem is when the alts get hot, they put out less amperage.

Another problem is these alts that do crazy high output like this do crap output at engine idle.

Ask me how I know... 

Because I have 3 390XP amp alternators that should produce 1170 amps of current, yet with 9 runs of positive and 9 runs of negative from alts to rear batteries, frame grounds front and rear.

Also had 2 XS Power S3400s under the hood, and 5 d3100s in the back. 

With 2 Sundown SAZ-4500s wire down at .35 ohms I had massive voltage drop down into the 11.2 volt range.

The thing with alternators is they wont make the power until they see a demand for it, so the  beat will drop and a couple seconds later your alternators yell at each other saying to wake up and get to work.

The thing with music is its not a constant sign wave, there is breaks in the beat and in those times your alts will then start to put out less current.

 

Reserve is needed no matter what.

All I changed in my truck is going from 7 XS Power batteries and 3 390XP alts to a 95ah CMAX bank and no agm with only have 1 of my 390XP alts hooked up at the moment and my voltage sits at 15.3 and never drops below 14.9 full tilt where as it use to be 11.3 volts with 3 alts.

Hey Audiofanaticz, that sounds like a pretty bad ass setup 👍 

Now, as far as the alternators dropping not putting out max rated amperage all the time, yes, of course. But when I was talking about making 2000-4000+ amps continuously, that was a whole different train of thought, that I don't have time or space to explain here.

 

Buts let's talk about your setup. Again, sounds freaking awesome 🙂 so when I said, "making LOTS of power but only having one battery", okay, let's make that 1 battery a Lithium Ion battery... Maybe even a 150ah version.

But also, I'd want to throw in a suitable sized bank of super capacitors, so that they could put out however much juice was needed "almost instantly". Even faster, in fact, than any lithium battery. 

 

So I'm imagining now, your system, with still only one battery, a 150ah lithium, all 3 alternators running again, and about 3000 farads of super capacitors. Honestly, I think that could do 30 or 40Kwts with almost zero drop.

 

So, everything I said, except yes, of course, if your only running one battery, definitely it should be a lithium. Don't know why I didn't address that in my OP...... But don't forget the super caps either.

 

PS, And again, I know a setup which put out 3000-4000 amps continuous could be built for any truck or SUV with a strong V8 or deisel motor. And you already see what "one" of your 390's does.

[MrSkippyJ]

Your alternators don't output power continuously, regardless of what you think the lower RPM output is. Alternators always react to electrical need. and they do it relatively slowly. 

[Fish Chris]

18 minutes ago, MrSkippyJ said:

Your alternators don't output power continuously, regardless of what you think the lower RPM output is. Alternators always react to electrical need. and they do it relatively slowly. 

Hence the need for "a battery".... either a lithium, which lets a lot of power out pretty fast... OR, much better yet, a lithium battery and a bank of super caps. Only problem with lithium batteries though, other than cost, is they have a limited charging amperage too.