Output @ Idle

M

Mel Jones

Noob
QUESTION: When an "Alternator Manufacturer" gives you an "Output at Idle" number - What do you want to hear? Most people just want to hear a high number and they're happy from that point on out.... Until they have 12.4 volts at a stoplight and 14.8 when they drive... Do you think they have been “deceived” lied to?


The industry standard for an "Idle output" test is 2400 ROTOR rpm. That's approximately 800 engine rpm if you have a 3:1 pulley ratio. It’s been that way for years...& as far as today that number should really be 2000 Rotor RPM instead of 2400 because crank pulleys have got way smaller on most vehicles which makes the "Output at idle" rating even LESS. Personally, I do not feel that any passenger car alternator on the planet will do 220 amps at 2000 rotor rpm.


To my knowledge there is not a single manufacturer that rates their alternators by this method. They all use the "Boss Audio Amplifier" rating method. (1000-watt amplifier rated at "4000 Watts".)


Do you want to be deceived and be told what the "best case scenario" is? Such as "XX amperage" alternator will do "230+ amps at idle" On "XX car"... which idles at 1000 rpm and has an 8" crank pulley which is typically a 4:1 ratio...


ANY THOUGHTS?...
View attachment 16280
 
Melissa_IraggiAlts said:
QUESTION: When an "Alternator Manufacturer" gives you an "Output at Idle" number - What do you want to hear? Most people just want to hear a high number and they're happy from that point on out.... Until they have 12.4 volts at a stoplight and 14.8 when they drive... Do you think they have been “deceived” lied to?


The industry standard for an "Idle output" test is 2400 ROTOR rpm. That's approximately 800 engine rpm if you have a 3:1 pulley ratio. It’s been that way for years...& as far as today that number should really be 2000 Rotor RPM instead of 2400 because crank pulleys have got way smaller on most vehicles which makes the "Output at idle" rating even LESS. Personally, I do not feel that any passenger car alternator on the planet will do 220 amps at 2000 rotor rpm.


To my knowledge there is not a single manufacturer that rates their alternators by this method. They all use the "Boss Audio Amplifier" rating method. (1000-watt amplifier rated at "4000 Watts".)


Do you want to be deceived and be told what the "best case scenario" is? Such as "XX amperage" alternator will do "230+ amps at idle" On "XX car"... which idles at 1000 rpm and has an 8" crank pulley which is typically a 4:1 ratio...


ANY THOUGHTS?...
View attachment 16280
Click to expand...
My car idles at 525 rpm, my alternator maintains 14.5 volts at whatever rpm it's spinning at idle, so I'm good with that. Also, I don't often drive my car at idle speed.
 
I've always hated how some amp manufacturers market "Max power"...but from a business standpoint, I can see why they do it. The simple fact is that most consumers just don't know any better, and they are going to buy what they think is the most bang for their buck, and any company that posts true output would get left in the dust. I can only assume the alternator business is no different. I have two thoughts on the matter:

Idea #1: Market the 2400RPM number as "Competition Idle", and put it in big bold letters. In smaller letters, put "RMS Idle" (or some other jargon) for 2000RPM idle, so that more knowledgeable people will know what they are really getting. This way, you wouldn't really be false advertising, you'll basically be following both the industry standard and giving the quality customers what they want.

Idea #2: Make two lines...an SPL "competition" line, with chrome or anodized cases, Bedazzled BS all over it, and impressive numbers at 2400RPM, and a slightly higher cost, to offset the cost of replacement (you know many of these guys will eff something up). The second line would be marketed towards the SQ guys and every day Joe. Give this line a basic case (with option for upgrade), marketed with real world numbers, and a decent price.
 
Unfortunately there's not much you can do about it.
Customers tend to flock to whomever tells them what they want to hear and you're just shooting yourself in the foot giving them too much information they cant understand.
We have always tried to give both the technical version and the layman version like saying that they'll get between X and XX amount of output depending on your exact vehicle.
 
Here's how mine was "rated" - shows alternator speed, which is rotor speed. Of course it's up to me to make extrapolations for my engine RPM. I know this performs way better than stock, so I'm happy.

View attachment 16287
 
Here's how mine was "rated" - shows alternator speed, which is rotor speed. Of course it's up to me to make extrapolations for my engine RPM based on my pulley. I know this performs way better than stock, so I'm happy.

View attachment 16287
 
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