So I have a delima. I have a Chevy Sonic and the stock alternator is only 100 amps. I cannot find an upgrade for it nor can I find anyone that can rebuild it to have higher output. My question is, what can I do to upgrade it? I have already done the big 3 and upgraded the stock battery. Any suggestions would be appreciated.

Hey there fellow Hoosier!

 

Who have you talked to so far about it?  I would imagine if you've talked to the likes of Mechman or DC Power and there's nothing they can do for/with the alternator then you're just SOL until which time they or someone does have something available for it.  Most people who've had this dilemma add at least a second battery depending on the power they're running and rely on the banked battery reserve.

As far as what you have installed in the vehicle car audio wise would work wonders in us answering your question?

You can take it to a local mechanical shop whom would "rebuild" it. I'm sure you can send the alternator itself to someone like Iraggi Alternator or Singer Alternator and they could do the same.

I've tried half a dozen local shops and they all have told me that the particlar can't be rebuilt. I currently have an Alpine MRP-M1000 powering a Sundown X-15 but I would like to upgrade my amp to maybe something around 1500 watts. I considered adding a second battery but not sure if my puny alternator can keep up.

Ok, a few of my recommendations

 

First, buy a volt meter, that way you can see what state you're currently in.

Next, upgrade all your wiring and their contact points (sand down to shiny silver lol)

I would suggest something like 2/0 welding. Local price should be around 3$/foot picked up.

Use that to do your big 3 upgrade.

Fit the largest AGM battery you can under your head. And fit the largest AGM battery you can in the rear. I would suggest something like the Sears Platinum if you're on a budget. 

 

After those upgrades, and 1500 watts, you should be ok. also, you're not going to hear a difference in 500 watts. If you do, it's because the ratings of the amps are incorrect. 

Yes your alt will be able to "keep up".