Alternator Upgrade Math - Help!!

[L-Series]

Wsup People.

I need help with an alternator upgrade requirement (calculation).

Pretty good in math but still learning about electricity.

Accord '99

regular battery (no yellow top yet)

Big 3 installed

4 gage from batt. to amps w/ 100a fuse

----

1200rms at 2 ohm (3000w mono)

350rms X4 at 2 ohm ( pzt1400- 4 ch)

**** Here's the thing

I came across this amp for dirt cheap and know it's overkill for pushing just one L7.

But i don't intend to push beyond 600-650rms ..period. gains are set.

The largest ALTERNATOR i've seen, online, is a 220a. Currently have a 110a.

How do I calculate whether or not the 220 will suffice?

Please chime in.. thanks

Click to read more...

 

[jtomsic 5,000+ posts]

ur current alt is fine for that wattage. do big 3 and maybe new batt if neccessary

 

[L-Series]

really? is that because of the 650 rms I'll be limited to ... or because the efficiency of the Class D? or what?

 

[CAT MAN 5,000+ posts]

well for every 100w it drwas 10 amps so the 110a alt you have the car that uses half if not more of that. so you have out of 110 50-60 amps to use for accecorries etc.

take that with what the amp draws 1200rms is 120a. so you have to cover an extra 60 amps with batery power. even if you get a new alt you need to have the batteries to store the power coming from the alt.

 

[jtomsic 5,000+ posts]

well for every 100w it drwas 10 amps so the 110a alt you have the car that uses half if not more of that. so you have out of 110 50-60 amps to use for accecorries etc.
take that with what the amp draws 1200rms is 120a. so you have to cover an extra 60 amps with batery power. even if you get a new alt you need to have the batteries to store the power coming from the alt.

hes not pushing 1200watts he said 600ish..

 

[L-Series]

got it.

Alternator's amps (110) - subtract 60a for car accessories.

subtract audio amplifier's draw = 10:1 ratio -watts/amps

compensate the negative balance with battery(s).

thanks for the info and prompt response. love this forum already

 

[i2ain2thunder 10+ year member]

You are correct, I like to use the fuse rating on the amps x voltage they run at for alternator calculation. IE if your system is running at 13 volts and never drops below that then your amp has a total potential to draw Fuse rating x 13 from the alternator. (of coarse in regular music you will never ever pull this much juice so whether or not you can get by with a stock alternator all depends on how your voltage is while your system is running. If you stay upwards of 12 volts with your most bassy music playing at full tilt you probally don't need to consider any electrical upgrades, if the opposite is true you do need to consider upgrading either batteries or the alternator, depending on the severity of the voltage drop. If it just barely drops below 12 volts maybe just pick up another battery, if it drops well below 12 volts say down to 10 or below you my friend should really get a high output alternator.

This isn't a complete explanation and isn't a perfect method for deriving power usage of your amplifier, but I Hope this helps.

 

[L-Series]

below 12 volts say down to 10 or below you my friend should really get a high output alternator.
This isn't a complete explanation and isn't a perfect method for deriving power usage of your amplifier, but I Hope this helps.

In such case.. a 220a should do? i need to get a volt meter to double check. So with my formula.. 110-60= 50a - 65 (averaging 650rms as to not blow the L7).

= (-15a) which an extra batt. should take care of. right? I do your method ..soon as i grab a meter.

 

[i2ain2thunder 10+ year member]

Yeah I think you should be good with the stock alternator but yes checking your voltage is the most important part of the process....its how we know our amplifier is getting enough power and both it and the sub are safe.

 

[Bggd_GMC 10+ year member]

i also been wanting to make a thread about this.... here is my situation... 1000rms at 1ohm and my 2nd amp is a total of 150rms on a 105amp alt....????

 

[i2ain2thunder 10+ year member]

i also been wanting to make a thread about this.... here is my situation... 1000rms at 1ohm and my 2nd amp is a total of 150rms on a 105amp alt....????

Personal opinion: get a second battery to help with the strain on your voltage and complete the big 3 and you will likely have ample power. However it is always best to check your voltage with a meter while your system is running for a long duration to ensure adequate power supply.

 

[Fi_ 10+ year member]

hes not pushing 1200watts he said 600ish..

Couldn't you tell by the way he types he can't read or write very well? give the man some credit.

 

[disturbed471985 5,000+ posts]

Toss a G31 in the trunk and go have fun...

 

[CAT MAN 5,000+ posts]

Couldn't you tell by the way he types he can't read or write very well? give the man some credit.

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif someone is mad butthurt. contribute some info or gtfo. i do not see you helping at all. at least he could use my info

 

[CAT MAN 5,000+ posts]

hes not pushing 1200watts he said 600ish..

and thats 60 amps so he can follow the equation im sure