can this be overloading my alternator?

The alternator in a 99 cavalier just went bad on me, eventhough its about a year old. Since I changed it, I added an amp to the car, its a 700w bazooka. The alternator in the car is 105amps, would that amp need a stronger alt?

Couple things. 1.sorry about your alt that sucks. Hope it dosent put ya off the road for more than a day or so. 2. There is no reason your 105amp alt cant handle your 700w amp. Not sure what the wiring looks like inside the cavi but something is wrong. Check and try these items.

1. did you upgrade the "Big 3"?
2. Is everything "grounded" right? I've seen a bad ground screw up the electronics so bad that the alt will burn out trying to keep up w/ the load. Just melt the coils right out.
3. How old is your battery? Because if your battery sucks your alternator has to work twice as hard and will eventually die out. I reccomend you purchase a new battery. Its more cost effective than a new alternator and when you do get a new battery check its status regularly. Like twice a week. Is the current still strong? Is it charging the way it should?
4. If you plan on upgrading your audio setup in the future you may consider a red-top battery. There a little bit more expensive but well worth it for high draw high demand systems. You can purchase them from most marine stores or directly from the manufacturur. I like Optimas battery's. Decent price good product.

Linkage Optima Batteries

If the amp is 700W rms, and class A (most likely), then at full power it will draw about 97 amps. If your alternator isnt powering much else then you should get away with it, but then of course your car does have headlamps, on board electronics etc, so you could be pushing the alt pretty hard. If you post the model number of the amp i can tell you whether this is actually the case, as i assumed a 700W rms output, when that may be the peak power and would definately not cause a problem.

I calculated the current draw by using power = volts x amps, and the fact that most class A amps are about 50% efficient. At 50% efficiency a 700W output requires a 1400W input. By rearranging the above formula, amps = power/volts ( 97 amps = 1400 watts/14.4 volts). Menaztricks, if you can verify that the amp is 700W rms, then the amp is definately your main problem. Additionally, i doubt the stock wiring in your car will be up to constantly carrying 100 amps or so. As desolationangel said, you should really upgrade the 'big 3'. Again, this all depends on whether your amp can actually give out 700W or not. The easiest way to find out the actual maximum output power is to look at the amp fuse rating(s).

I doubt a bazooka amp will ever put out 700W lol. I definitely agree with everything desolationangel said. He pretty much nailed all the entry level stuff.

700 watts with a good wax job, a long downhill, and a stiff tailwind, maybe.

Probably more on the order if 250 to 300 watts, if that much. It won't be a Class A amplifier, pretty much guaranteed. Class A/B, more likely, but still, IF it's recent enough, it could still be a Class D amp.

Class A is actually closer to 30-33% efficient, Class A/B is more like 55-66% efficient, and Class D can acheive 95% efficiency.

But, yeah, look at the fuses, add them all up, for total current capacity, multiply by 14.4, and then multiply by .3 for class A, .66 for A/B, and .95 for Class D. To save you the hassle, assume Class A/B. These formulae will give you the true, real-world continuous output, peak.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

I would go with desolationangel's number 1 selection. Upgrade the "Big 3". That in itself may take care of your problem.

I know better than to argue with haem's calculations.

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The Flakman
I feel strange. I have deja vu and amnesia at the same time.

John | Manteca, CA

haemphyst is right about the efficiency ratings, i was confusing class A with class A/B