Will a High Output Alternator Fry my car's Electrical System?

Bumpin' Yota

CarAudio.com Elite
Mar 10, 2003
963
0
FL
Mods, could we sticky this?

If properly used, no.

I've heard many people (including some mechanics) run off at the mouth about how getting a HO alternator will fry all the wires and destroy your car's electrical system and blow every bulb in your car...

Nothing could be further from the case.

If the proper alternator is selected, installed and operating properly, it will charge up to about 16.0v at the absolute most when cold. Typically after warm up, it will charge everything at 14.4v. On REALLY hot days, it may drop its voltage to 13.8v.

Nothing in your car will be stressed. It is the nature of a generator (alternator) to only supply enough current as is needed, so usually it's just trickle charging the batteries and up keeping the car's electronics.... This is the case for a stock honda 40amp alt or a 350ampre big case custom alternator.

Part of a PROPER install is ensuring the alternator has a sufficient size wire to the battery. If you have more than 150amp alt, I would highly suggest using nothing smaller than 1/0ga to connect the battery and alt.

If you were to use, say, 8ga as a charging wire to the battery when using a 350amp alt, and you suddenly need that 350amps the alt can kick out, you WILL fry that single 8ga wire....

Most alternators come with an internal voltage regulator that keeps the alternator's charging voltage from 13.8-15.5v at all times. Others have external units that allow you to change the voltage the alt charges to.

Voltage is a different beast than current.

Too much current over a small wire will overheat it VERY rapidly and possibly induce failure. However it is VERY difficult to overload a wire with voltage. I'd place a good bet that most of you underhood wires can conduct 500+ volts without much trouble. (Your sparkplug wires carry 10,000volts if I remember correctly, but very LITTLE current...)

The electronics in your car, on the other hand, are sensitive to both current AND voltage. Spikes above 18vdc could very well destroy your car's ECU, bulbs, etc. Current is not an issue as the electronics will only see as much current as they need.

Now to the FOLKLORE/Wive's tales....

I would venture that in the past people saw Racing Alternators and tried to use them in their own cars. Racing units produce a LOT more voltage than normal. (Typically they use 16v.) So most of those alts will charge at 18-21volts DC and that high of a voltage WILL incinerate most of your car's electronics. I believe this is were that folklore began, and is why I said you must select the proper unit for your car.

I've heard the analogies too....

"A HOalt is like a firehose where as your stock alt is a sink facuet. If your faucet had the pressure of a fire hose it would punch a hole in your sink."

Another falsehood, first off the pressure in a firehose and your sink are equal or very close - there is a reason you use schedule 40 PVC or better in your house. The difference is the VOLUME of water being propelled.

Secondarily an alt will only produce enough current as is needed. And if it does go to full power, that current will ONLY go to the electronics that are demanding that much current. So you anticipate where this current is going to go, and beef up those wires. (Big 3 wires, and power wires for your amps.)

This is why a HOalt is COMPLETELY safe for your vehicle. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

And I HIGHLY recommend, and use, http://www.hoalternators.com

 

tRiGgEr

CarAudio.com Veteran
Jan 27, 2004
13,390
78
San Diego, Ca
"A HOalt is like a firehose where as your stock alt is a sink facuet. If your faucet had the pressure of a fire hose it would punch a hole in your sink."

Another falsehood' date=' first off the pressure in a firehose and your sink are equal or very close - there is a reason you use schedule 40 PVC or better in your house. The difference is the VOLUME of water being propelled.

[/quote']

Not true.

...............
 

Nikuk

Been Gone Too Long
Jul 13, 2004
8,002
0
Buffalo, NY
"A HOalt is like a firehose where as your stock alt is a sink facuet. If your faucet had the pressure of a fire hose it would punch a hole in your sink."
Another falsehood' date=' first off the pressure in a firehose and your sink are equal or very close - there is a reason you use schedule 40 PVC or better in your house. The difference is the VOLUME of water being propelled.[/quote']

isnt this a similar idea to more port area is better because of less velocity? sorry, if i make it worse... //content.invisioncic.com/y282845/emoticons/banghead.gif.8606515f668c74f6de0281deb475b6fd.gif
 

Bumpin' Yota

CarAudio.com Elite
Mar 10, 2003
963
0
FL
Not true.
...............
Both are supplied by the same water mains, so they start out with the same pressure.

However this is NOT the point. The analogy was FLAWED to begin with...//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

iceteebone

Banned
Aug 5, 2003
39,411
225
Michigan
i think i get what he is saying. the water is running at the same pressure through a fire hose as your kitchen fawcet. it's just that a fire hose has more water not pressure therfore a bigger hose is needed. am i close? //content.invisioncic.com/y282845/emoticons/titanic.gif.8089b7552c370bcc138aa121756d0c0b.gif

 

ss3079

Eh Dere Hi Dere Ho-ser
Mar 22, 2002
37,261
144
Up North
Stuck ... in the electrical section. Can't have more than two threads stuck per forum, and General is already taken ... so we'll shove 'er here.

Add more ... always enjoy reading up on this stuff. I need a new alt, too //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

- Steve

 

Gauntlet

bulletproof
Oct 23, 2002
8,336
5
Cleveland, Ohio
Stuck ... in the electrical section. Can't have more than two threads stuck per forum, and General is already taken ... so we'll shove 'er here.
- Steve
Not true.
...............
Check the box forum. //content.invisioncic.com/y282845/emoticons/handclap.gif.0c301076f534e244f0460706894f19e0.gif

 

ss3079

Eh Dere Hi Dere Ho-ser
Mar 22, 2002
37,261
144
Up North
Check the box forum. //content.invisioncic.com/y282845/emoticons/handclap.gif.0c301076f534e244f0460706894f19e0.gif
Unstick your fiberglass tutorial and link it in under the fiberglass links //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

- Steve

 

Bumpin' Yota

CarAudio.com Elite
Mar 10, 2003
963
0
FL
nice. plus all house water has a regulator. but mine doesnt for1 hose in my yard.

ive broken 2 hoses with 250psi and a little noosle.

need to upgrade to better hose.
ROFLMAO!! Pressure washer?!? Who needs a pressure washer?? //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

supraman1379

Lifted 03 HEMI
Mar 23, 2004
3,180
0
Ocala, Fl
If a HO alt. frys electricle systems, consider mine fried....NOT, thats a bunch of shit cuz mine cam with the HO alt, stock and it hasnt fried my ekectrile system

 

JoseMCeee

$tack
Sep 29, 2004
2,258
1
Bay Area, CA
What would be a good alternator for a 03 Cavalier?

My System:

HU: Alpine CDA-9827

Front: Kicker 5 1/2 Components

Rear: Kicker 3-Way 6x9's

4 Channel Amp: Sony 360 watt rms

Subs: 2 Kicker L7 Ten Inche 600 watt

Sub Amp: MA Audio HK-1997 1200 watt rms

 

amedeuce

:crap:
Jan 1, 2004
1,825
0
CA
Bernoulli's Principle

This is an important principle involving the movement of a fluid through a pressure difference. Suppose a fluid is moving in a horizontal direction and encounters a pressure difference. This pressure difference will result in a net force, which by Newton's 2nd law will cause an acceleration of the fluid. The fundamental relation,

Work done = change in kinetic energy

in this situation can be written as

(change in pressure) x area x distance = change in kinetic energy, which furthermore can be expressed as

Change in pressure + change in (kinetic energy / volume) = 0.

In other words, Pressure + (kinetic energy /volume) = constant

which is known as Bernoulli's principle. This is very similar to the statement we encountered before for a freely falling object, where the gravitational potential energy plus the kinetic energy was constant (i. e., was conserved).

Bernoulli's principle thus says that a rise (fall) in pressure in a flowing fluid must always be accompanied by a decrease (increase) in the speed, and conversely, if an increase (decrease) in , the speed of the fluid results in a decrease (increase) in the pressure. This is at the heart of a number of everyday phenomena. As a very trivial example, Bernouilli's principle is responsible for the fact that a shower curtain gets ``sucked inwards'' when the water is first turned on. What happens is that the increased water/air velocity inside the curtain (relative to the still air on the other side) causes a pressure drop. The pressure difference between the outside and inside causes a net force on the shower curtain which sucks it inward. A more useful example is provided by the functioning of a perfume bottle: squeezing the bulb over the fluid creates a low pressure area due to the higher speed of the air, which subsequently draws the fluid up.

Bernouilli's principle also tells us why windows tend to explode, rather than implode in hurricanes: the very high speed of the air just outside the window causes the pressure just outside to be much less than the pressure inside, where the air is still. The difference in force pushes the windows outward, and hence explode. If you know that a hurricane is coming it is therefore better to open as many windows as possible, to equalize the pressure inside and out.

Another example of Bernoulli's principle at work is in the lift of aircraft wings and the motion of ``curve balls'' in baseball. In both cases the design is such as to create a speed differential of the flowing air past the object on the top and the bottom - for aircraft wings this comes from the movement of the flaps, and for the baseball it is the presence of ridges. Such a speed differential leads to a pressure difference between the top and bottom of the object, resulting in a net force being exerted, either upwards or downwards. This is illustrated in the following figure.

 

amedeuce

:crap:
Jan 1, 2004
1,825
0
CA
Simple version The principle states that when a fluid flowing through a tube reaches a constriction or narrowing of the tube, the speed of the fluid passing through the constriction is increased and its pressure decreased.

What this has to do with HO Alts I dont know................

 

jlhead

Junior Member
Dec 6, 2004
1
0
fullerton,ca
You seem pretty knowlegdeable, What would a jl12w7 3ohm subwooffer run a 4ohm amp at. I mean will i have enough power. I have a Lazar 268 bridged 2000 watts. It was bench tested at 930watts.

 

SPL140.2

Team DefJ
Mar 1, 2005
5,342
13
NY
Mods' date=' could we sticky this?

If properly used, no.

I've heard many people (including some mechanics) run off at the mouth about how getting a HO alternator will fry all the wires and destroy your car's electrical system and blow every bulb in your car...

Nothing could be further from the case.

If the proper alternator is selected, installed and operating properly, it will charge up to about 16.0v at the absolute most when cold. Typically after warm up, it will charge everything at 14.4v. On REALLY hot days, it may drop its voltage to 13.8v.

Nothing in your car will be stressed. It is the nature of a generator (alternator) to only supply enough current as is needed, so usually it's just trickle charging the batteries and up keeping the car's electronics.... This is the case for a stock honda 40amp alt or a 350ampre big case custom alternator.

Part of a PROPER install is ensuring the alternator has a sufficient size wire to the battery. If you have more than 150amp alt, I would highly suggest using nothing smaller than 1/0ga to connect the battery and alt.

If you were to use, say, 8ga as a charging wire to the battery when using a 350amp alt, and you suddenly need that 350amps the alt can kick out, you WILL fry that single 8ga wire....

Most alternators come with an internal voltage regulator that keeps the alternator's charging voltage from 13.8-15.5v at all times. Others have external units that allow you to change the voltage the alt charges to.

Voltage is a different beast than current.

Too much current over a small wire will overheat it VERY rapidly and possibly induce failure. However it is VERY difficult to overload a wire with voltage. I'd place a good bet that most of you underhood wires can conduct 500+ volts without much trouble. (Your sparkplug wires carry 10,000volts if I remember correctly, but very LITTLE current...)

The electronics in your car, on the other hand, are sensitive to both current AND voltage. Spikes above 18vdc could very well destroy your car's ECU, bulbs, etc. Current is not an issue as the electronics will only see as much current as they need.

Now to the FOLKLORE/Wive's tales....

I would venture that in the past people saw Racing Alternators and tried to use them in their own cars. Racing units produce a LOT more voltage than normal. (Typically they use 16v.) So most of those alts will charge at 18-21volts DC and that high of a voltage WILL incinerate most of your car's electronics. I believe this is were that folklore began, and is why I said you must select the proper unit for your car.

I've heard the analogies too....

"A HOalt is like a firehose where as your stock alt is a sink facuet. If your faucet had the pressure of a fire hose it would punch a hole in your sink."

Another falsehood, first off the pressure in a firehose and your sink are equal or very close - there is a reason you use schedule 40 PVC or better in your house. The difference is the VOLUME of water being propelled.

Secondarily an alt will only produce enough current as is needed. And if it does go to full power, that current will ONLY go to the electronics that are demanding that much current. So you anticipate where this current is going to go, and beef up those wires. (Big 3 wires, and power wires for your amps.)

This is why a HOalt is COMPLETELY safe for your vehicle. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

And I [b']HIGHLY[/b] recommend, and use, http://www.hoalternators.com
The best example i can come up with is this: Say you get your water from the town to your house. The towns water is usually stored in a huge water tower. It has lots and lots of water, you turn your facuet on and only get a stream, you dont get flooded, thats because your house may only have a 1 inch line. Its basically the same for a high output alternator. Having the extra amps wont hurt your electrical system. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif Its better to have the extra amps!!!!