Is my alternator big enough?

eyeballumbrella · Post by **eyeballumbrella** » 02 Jul 2009, 18:31

I am thinking of putting a JL Audio 12w7 in my 98 volvo s70. I know the car has a stock 100 AMP alternator but the question is, is this enough? (the 12w7 runs between 750-1000 rms) Also if it isnt anyone know a bigger alternator I can put in? or another solution?

Thanks!

FCPEURO · Post by **FCPEURO** » 13 Aug 2009, 07:33

I think you will be fine as long as you put in a capasitor to help the system. I know there is a bigger alternator that fits, I am just not sure that it is.

GrumpyOldMan · Post by **GrumpyOldMan** » 16 Aug 2009, 00:23

Capacitors are only a band aid for those that don't want to do it the proper way.

The power rating of the sub means nothing.
The power draw of the amplifier is what you should look at.
And even then it is only a guide.

I doubt very much that a properly designed system will bother the 100amp alternator that these cars come with.

Worry more about your battery and wiring......

Example (NOT ACCURATE, EXAMPLE ONLY),
Say at top speed (300kph) your car uses 20 liters a second of petrol.
How often do you drive at this speed ?
Never, so why worry about the petrol consumption ??

FCPEURO · Post by **FCPEURO** » 17 Aug 2009, 08:50

True, the capacitor is a band aid, but it is better then not running anything. Either way, he will be fine.

GasVehicles · Post by **GasVehicles** » 17 Aug 2009, 15:07

Depending on the
1. Alternator
2. single or multiple batteries (1 dedicated to the stereo)
3. the type/age of the battery (older batteries do not release or take a charge efficiently or quickly)
4. typical music preferences (most soft rock and classical requires very little current for bass when compared to Hip Hop or Rap)
5. and the amplifier- efficiency - power draw capability
A large (1 farad) capacitor may or may not be a Band-Aid. Example: Even with a 200A alternator and a dedicated 1200 CCA battery, the battery alone w/o a cap would not be able to supply the current quick enough for 4 12’ at 1500W each, with multiple consecutive (>.3 sec) bass hits.

A capacitor won’t ever hurt your system if installed correctly and can reduce or eliminate the ‘brown out’ of headlights when the amp is taxed.

Take your car to the local auto store (Advance Auto) and have them check the electrical (battery/alternator) for free to make sure they are in good working order

After you install your stereo keep an eye on the battery voltage.

Safety note: A 1 farad cap can knock you on you’re a-- and fry your fingers.

PS I recommend you ask this question on an audiophile forum … you will get much better results.