i have a alpine mrd-t707 2 channel running my 2 subs and i'm about to get 2 mrd-m301 monos to run them and use the 2 channel for front speakers.

i heard alternators can only supply a certain amount of watts so is my standerd eb alternator going to be able to keep up. my lights in my car dim lightly already when i crank it.

thanks

antony

Hi Anthony,

Your headlights are probably dimming due to insufficient capacity ground cable between your chassis and your battery. This is why I always recommend AGAINST grounding to the chassis.. ground direct back to the battery terminal. If you insist on grounding to the chassis, then ensure that you have more than sufficient capacity ground cable from the chassis to the -ve battery terminal.

I have a Rockford Fosgate Power 1000.2 (1500W RMS x1 @ 4 ohms) and an Alpine V12 MRV-1005 (600W RMS x1 @ 4ohms). With the factory alternator (105A) and a single battery (with both amps running 4GA direct to the battery) I dont get any headlight dim.

Whats more interesting is that my car is a V8 with an underdrive kit, which means the alternator isnt even charging at idle (it doesnt begin to charge until 1800rpm) - despite this, I still dont get headlight dim Go figure.

A good battery, and good cabling will support most systems without any hitches.

I second that, 4GA minimum for decent amps and no less than 600 cca battery

thanks for he help. i'll check that all out and hopefully it will fix the problem.

antony

On the topic of alternaters, I had my bearings stuff up a while ago, and it kept throwing belts (before the bearings went, due to the tensioner being destroyed) Anyway, I had my bearings replaced, and refitted the alternator, but now, when i first start the car the alternator light comes on, and stays on. Even if its left to idle for an hour, the light wont go off. Bring the revs to about 1400, the light goes out, and remains out, even if the motor is left to idle again. I cant figure it out :S It never used to do it before, and the guy who replaced the bearings for me said that it charged fine on the bench. Any ideas?

sounds like the builtin regulator in the alternator is a little lazy, if the light stays on all the time during normal driving then it will need to be changed.
but since it goes out when you boot it i wouldn't worry about it

Regarding batteries.. I'm using a single Optima Yellowtop. I'm planning to expand that to 2 Yellowtops in the boot, and a single Red Top for starting.. just to cut down on power cable runs from Amp <-> Battery plus isolation so I dont kill my starting battery.

sounds like an expensive plan, is it nessecery though??

Sure.. I like to be able to start my car after being at the drive-ins

Isolation is the big feature. The only outlay required will be the purchase of the Redtop. Already got 2 spare Yellowtops

Light only stays on at initial start up. Once it hits 1400 rpm for the first time, it goes off and stays off, even if i drop it back to idle. Has never come on after going off the first time. Confusing