How big of an alternator do I need?

[audiolife 5,000+ posts]

65x4 +300= 1000? ok

 

[da12b 10+ year member]

The tested rms of my amp is (which I'm using):

56 rms x4 @ 4 ohms

381 wrms x1 @ 2 ohms

Keep in mind that this testing is at 12.5 v

I did my own calculations @ 14.4 v

107.5 wrms x 4 @ 4 ohms

481 wrms x1 @ 2 ohms

which equals to 911 wrms @ 14.4 volts

I did not do any calculations prior to last post. Sorry

 

[audiolife 5,000+ posts]

2 volts wont double your amps output lol besides that your calculations at best would be with test tones not music............................

 

[WhoSayWho? 5,000+ posts]

Check out http://www.4alterstart.com
I bought a 180A Alt for about $350. It was the best audio performance I did. I went through 2 DieHard batteries, 2 Optima (1 Red Top and 1 Yellow Top) hoping that the yellow top would help, but it lasted for just over 2 years. In fact, the batteries I bought lasted only 2 years, with the OEM alt. I spent approx. $450 on just batteries alone.

You know, in fairness to those who read your repeated post of this (and may actually rely on your testimonial) you should add in your statement that you have had this alternator for about three weeks.

You could say something like, "I have had this alternator almost 21 days and I have not had to replace my battery once during that entire time. And I am running nearly 1,000 max rated RMS"

Just try to be fair to people.

Hell, knowing that everyone else seems to hate those alternators and your own experience with them is extremely limited, why not just say, "I like mine, but you may want to get some other opinions, because everyone else thinks they are junk."

Or just STFU.

 

[audiolife 5,000+ posts]

i think you would need to years to evaluate what you are saying as true lol i agree with who

 

[SQBubble 10+ year member]

100.2 is going to be ~14a max draweach 1500d will be ~140a max so you aer looking at ~70a for both on a daily setup.

You will need atleast 84a extra current bare minimum.

You car is going to need about 60% of your current alternators amperage to run so whatever that is take the A and multiply it by .60 to see what the car needs. Then find one with an amount that will not overload it. Finally...an extra set of batterys will help out with the amperage demands. I dont see you keeping a good 14v charge however.

I am a little drunk so someone please check my math.

how do you calculate an amplifier's max current draw?

 

[Decipha 10+ year member]

i don't know how they calculate it but the way i calculate amperage draw for systems i design i base off 14 volts with 80% effeciency.

for example...

watts / volts / effeciency

in my case

3000 / 14 / 80% (.8) = 267 amps which is about right because at close to full tilt i pop my 250 amp fuse under the hood which is beginning to get annoying

 

[SQBubble 10+ year member]

i don't know how they calculate it but the way i calculate amperage draw for systems i design i base off 14 volts with 80% effeciency.
for example...

watts / volts / effeciency

in my case

3000 / 14 / 80% (.8) = 267 amps which is about right because at close to full tilt i pop my 250 amp fuse under the hood which is beginning to get annoying

thx for the input, where the efficiency come from??