running an amp off the alternator?

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the_junkie

running an amp off the alternator?

#204137

Post by the_junkie »

I know that one of the locals does it, but could I, say, run a 4 or 6 pill directly off of an alternator? with possibly an inline voltage regulator?

I'm just curious, because if that is possible, I may consider doing that with my newly planned charging system
ringer
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#204140

Post by ringer »

the alterator isn't a power source
the_junkie

#204142

Post by the_junkie »

ringer wrote:the alterator isn't a power source
if that is the case, then how is his amp working ? I don't know about the subject myself, i'm no mechanic, but he is gettin about 1 kw out of his 4 pill straight off the alternator. He also has a farad cap inline, which I was told won't work for cb amps...

but it screams! lol
TheTeZ

#204150

Post by TheTeZ »

not a power supply....? doesnt the alternator create current?
this is an honest question....... not a "shut up stupid your wrong" because i honestly dont know...

anyway...
i would think you would need a high idle alternator because, when your not moving, the thing may not put out enough power to power your amp..... and dont expect to run the amp when the vehicle is off....

(if even possible)
bettyboop

#204170

Post by bettyboop »

Think about it junkie. You answered your own question. What is the difference between your buddy and you.
You sit there and type (He gets out great). WOW!
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#204173

Post by Foxhunter »

Most guys will stay away from the alternator as a direct power source. The noise & interference it generates directly is not radio-friendly.

People rely on "a buffer" of sorts like a battery to help filter-out some of the trash generated by the alternator. Additionally capacitors or filtration can be further utilized. You'd hate to hook "straight to the source" of the part of the car generating the most electrical noise.

I did this once, going directly off a very heavy-duty alternator while experimenting. Excellent current output but 5x the noise level. It was a good idea (or was it?) with bad results.

I'd like to comment a bit on the nature of alternators a little bit if I may.

Even those who are somewhat familiar with automotive DC wiring principles don't realize or know the following:


:idea: A vehicle alternator produces ALTERNATING CURRENT (AC) ! :idea:

The majority of noise & hum that interferes with radio is AC generated. An alternator is virtually the same in design as the "switching power supplies" so commonly used at home by CB & Ham operators for non-linear power supplies.

Many guys think that AC is house current only. An alternator directly produces AC power ! A series of diodes & rectifiers block the passage of AC, allowing only DC Direct Current to pass. Thus it becomes a "12V DC" system. It starts out as AC and is converted to DC.

Now unfortunately many alternators don't completely filter out the AC because of a faulty component (often one or more of the many diodes). You may get a "noisy alternator" brand new right out of the box. *This is especially true of "rebuilt" alternators and "brand x" manufacturers.* When at the auto parts store, comparing prices and about to buy----remember what I am saying here. If you go for the "cheap one" you will quadriple your chances of getting a noisy one. You have more of a chance of "quiet", by getting a better grade alternator, one from a quality manufacturer and that is heavy-duty in nature.
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#204176

Post by North Texas Mudduck »

sounds like hes not telling all the facts

for one hes not running is 4pill directly to the alt
and powering it

he may have it hooked right at the alt charge post but hes running a battery with it

and the cap is useless on cb amps

reason he has the amp hooked directly to the alt is because hes afraid of not getting enough volts and amps to his battery

but hes just cutting corners
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#204198

Post by Slim »

also going directly to an alternator, you will really only get spikes of energy. the alternator will not charge as much when you are not accelerating, and give you a much larger charge when you are accelerating
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#204209

Post by Grump »

i wouldn't do it cause your altenator does not supply a steady supply of power meaning it changes voltage which cant be good on your amp
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#204212

Post by rotts4u »

Since the alternator is connected directly to the battery usually with a nice large diameter cable isnt hooking it to the "alternator" the same as hooking it to the battery except with the longer cable? Because the alternator is infact connected to the alternator anyway right?
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#204223

Post by jessejamesdallas »

rotts4u wrote:Since the alternator is connected directly to the battery usually with a nice large diameter cable isnt hooking it to the "alternator" the same as hooking it to the battery except with the longer cable? Because the alternator is infact connected to the alternator anyway right?
The battery is going to buffer the charge coming from the alternator, and give you a more constant current flow. (no Up & Down spikes in current)

In junkies "Buddies" case, he stated that this guy had a farad cap inline...OK, even though these are not recommended for use in CB installs, in this case, the Cap is acting as the battery, and giving some buffering probably to his set-up. But I would be willing to bet this guy also has allot more noise in his radio, than he would if he had a battery in line rather than that Cap.
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#204285

Post by coondog »

no way would i ever think of running a setup like that,imagine how hot the alt. would get and i guess he dosen"t even use his amp at night because he"d be driving in the dark.

if he"s using the mobiles main alt.for this i feel sorry for his mobiles computer.

there has to be a battery somewhere in the mix or he"d be dead in the water in no time.
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#204307

Post by Grump »

Oh Yeah junkie I just remembered one thing these newer cars are strange when it comes to the charging system cause of the computers they have. If he keys up to much probably will kill the computer real quick and I really would hate to replace a computer
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#204320

Post by Crusher »

I ran a 6 pill in my 2000suv. It hurt the computer system. luckily the dealer was able to rest/reprogram the computer. I also smoked a sensor. I ended up using a motormaul and now am running an 8 pill. The only thing affected is that i get the voltage light to come on around 600-800 Bird watts. I am only saying this as i thought originally I had upgraded to a drop in replacement alternator that was rated at 220A verses the factory 100A. I thought I had amps to spare, but I was wrong. Upgraded alternator cable from 4 gauge to 2 gauge. I have killed several alternators in many of my vehicles. It becomes an expensive lesson.
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Re: running an amp off the alternator?

#239374

Post by manonegra »

i run my 3x6 pill on my 180 amp altenator and voltage regulater on a two 12 v battery no more then 15v and i get about 700 rms bird watts and pep 1600 watts so far not a problem on my subervan.
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Re: running an amp off the alternator?

#239376

Post by manonegra »

this is a temporaty set up, thinking to put that on the side with two 12v and 6v for 18v set up and use my stock altanator for the rest of my truck,hope it works 454 snakeeyes got downnnnnnnnn.
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Re:

#239396

Post by RC2002 »

the_junkie wrote:
ringer wrote:the alterator isn't a power source
if that is the case, then how is his amp working ? I don't know about the subject myself, i'm no mechanic, but he is gettin about 1 kw out of his 4 pill straight off the alternator. He also has a farad cap inline, which I was told won't work for cb amps...

but it screams! lol


The wire that he hooked the amp to on the alternator is also the feed line (charge)for the battery so Hed' get more power right at the battery. the alternator just charges and the hot wire goes to the battery and he has it just eyed in at the alternator over the battery... if he tells you diffrent hes blowing smoke!@
'Doc

Re: running an amp off the alternator?

#239400

Post by 'Doc »

Think about it. The output from the alternator goes to the input of the voltage regulator, and the output of that voltage regulator goes to the battery. That's normal. Some times that voltage regulator is built into the alternator, sometimes a separate thingy. doesn't matter. If the input to the amplifier power line is connected to the output of the regulator, there's no difference than if it was connected to the (+) post of the battery. If that supply line to the amplifier is connected before that regulator, it won't be working very long, that's a guarantee! Doubt seriously if it's NOT connected to the output of the regulator. I think there's a lot of 'hoop-la' about nothing here.
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Re: running an amp off the alternator?

#239406

Post by manonegra »

dont know if i have the right way, but this is how i have it the field from the alt to the regulator the alt output direct to the battery 12v in the back and only went im goin to key i may ajust the regulater a lit as may be 16v and wend key it my drop to 15v wont try it any higher so i wont burn somethings up so far has work for me but this is a temporary set up.
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Re: running an amp off the alternator?

#239407

Post by manonegra »

I drive a 454 big block 89 suverban just like i said whith two fitting monkey made stick both hot 3x6 on a altenator with out side regulater on 12v batt set up work like a champ now if anything is rong on my set up please let me know i apreciate the help im new and i dont get to much help around i did everything my self....73s killadelphia north east side.
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Re: running an amp off the alternator?

#239439

Post by Sheriff Bart »

manonegra wrote:I drive a 454 big block 89 suverban just like i said whith two fitting monkey made stick both hot 3x6 on a altenator with out side regulater on 12v batt set up work like a champ now if anything is rong on my set up please let me know i apreciate the help im new and i dont get to much help around i did everything my self....73s killadelphia north east side.
I think you should get that extra battery soon because if you're continually volting that 12V battery with 15V you're going to be smelling sulphuric acid real soon as your 12V battery cooks.


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Re: running an amp off the alternator?

#239528

Post by manonegra »

i use 1000cca in front and two 1100cca school bus battery any way my point is you can run this type of set up too not the best but for some one that stating on the hobby would work find.no more 16v and on quick keys wont heard nothing. :r&r:
philadelphia pa np
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at 15v on 12v batt set up for now
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Re: running an amp off the alternator?

#239557

Post by Sheriff Bart »

manonegra wrote:i use 1000cca in front and two 1100cca school bus battery any way my point is you can run this type of set up too not the best but for some one that stating on the hobby would work find.no more 16v and on quick keys wont heard nothing. :r&r:
okay...the original premise is "running an amp off the alternator" ...answer, how do you run it when the engine isn't running :basketball: ...now to cross you over.. THE AMP NEEDS TO ALWAYS BE CONNECTED TO A BATTERY OR SERIES OF BATTERIES WITH A CABLE LARGE ENOUGH TO HANDLE THE AMPERAGE DRAW...PERIOD anything else and you're inviting poor performance or worse. I don't care what cold cranking amp rating you're using, 12V is 12V. if your regulator is at 15V you are overvolting those batteries. An alternator with internal regulator will recharge a 12 V system at a range of 13.8 to 14.4 volts and taper back to 12v after you start your engine (which is a big current draw)..key word "taper back"..if you keep it at 15V no matter who makes the battery, whether it's a red top a gel cell or plain old water and sulfuric acid it will cook....talk to some of your big gun homies, lights out or fancy dancer, they'll get you on the correct track. :basketball:

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Re: running an amp off the alternator?

#239612

Post by manonegra »

10-4 on that yea well light out is going to put that altenator on the side this is just the way im running in the mean time and it works but i under stand that if i keep running this way my battery wont last for long so far has work for me thanks for the come back 73s.
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Re: running an amp off the alternator?

#239683

Post by MECHMAN »

An alternator HAS to have a battery in order to produce current. It needs the initial current from the battery to fire up the field for the first time, as well as supply current tothe regulator.

Even if that weren't the case, all regulators have a delay built into them, and amperage output would be all over the pplace with RPM changes. You pretty much have to have a battery in parralel with the alternator to power anything. (not just a radio) He more than likely was just running his power cable from the radio to the alternator stud, but he had to have a batter in the circuit somewhere.

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