I am looking to install an aftermarket Alpine headunit under the dash. I plan on cutting the existing power cable that goes original stereo and directly connecting. I want to put 4 6x9 Kicker speakers on the rear deck which are 75w RMS each. I would need a 300w amp. Would my 65amp generator be able to handle that much power. My GEN light is constantly on but I put a new alternator in 2 months ago and it charges at 14.2v when driving. Havent have any charging issues since replacing it. Running a red top Optima battery.

68 Cutlass Supreme

 

Simple put......No.

Here's how you design a system.
#1. Pick what speakers you want. Determine RMS power requirements.

#2. Pick your amps that can supply the needs of the speakers. If you do subs, you'll need more then 1 amp unless it's a 5 channel.

#3. Pick the alternator that can supply the power to the amp(s)

A stock GM Alternator was designed by GM engineers to supply the vehicles needs that rolled off the assembly line. An aftermarket stereo with external 300W amplifiers was not in mind. FYI too, that 65amp alternator only puts out ~1/2 that at idle. Have guys done it the cheapo way without upgrading?? Yeah, just like a redneck uses duct tape to put their door back together.

If you want to install an aftermarket stereo with 1 or 2 decent amps to power it , then you will need to look at a 100-140amp alternator. Depends on how big the amps are, because that's what draws the power. When I put my CS130 140amp alternator in my '70 442 clone I called Kicker directly and asked them what amp draw each amp I was looking at had and what they recommended. They told me my ZX350.4 Kicker amp should have a space of 40amps. That's obviously MAX draw on full blast.

 

10DN and 10SI alternators only put out about 1/4 to 1/3 of their rated hot output, at an idle.


bill

 

Since you just replaced your alt, use it for a while and see if it will work for ya.
What the alt cannot provide, the battery will. A temporary volt meter set up in the car will help you monitor how well the alt does. Needs to stay above 13V. Some meters are sold that will plug in the lighter socket!

Your amp will be drawing 30-40A only at musical peaks (based on a good 300W RMS amp). Current draw will be kinda proportional to the loudness of the music. On a continuous average, maybe 20A, but that depends on the music itself and how much 'body' it has. Of course you will not have it cranked all the way all the time, so just see how it does. What kind of tunes will it be playing?

If you plan to drive at night with both the A/C on high and the music blasting very loud for many miles, an upgraded alt may be needed.

I put a good 200W amp in my '72, and the 63A alt does well even with it cranked up at night. Not sure how it will do with the A/C on, but I will find out when i get it fixed in a few years.

Wiring the amp right to the battery is the way to do it. Be sure to have a quality inline fuse in that line next to the battery.