Just replaced the alternator works fine but when I turn all electronics on stops charging, what could be wrong?

Gauges going wild suggests bad news - I hope I am wrong but it is the sort of thing that happens when a battery or jump starter is momentarily connected the wrong way around - fully computerised car with lots of electronics that are easily damaged.

Alternatively perhaps a wire hasn't been connected that should have been.

It might have been helpful if you had provided more details, such as when the trouble began - did you replace the above because it wouldn't start or perhaps it wouldn't start after the replacements?

The voltage regulator is built into the alternator. If the wires in the alternator connector are good, the problem is in the alternator. Take it back to the shop.

With GM cars in general, I have found it is best to change the battery and alternator both out together. If one is weak it will take out the other in no time. These parts are both dirt cheap at a junkyard. Believe it or not, a junkyard delco alternator or battery is much better than a duro=last silver rebuilt in mexico.

You may also still have wiring problems remaining from the previous failure. GM dummy lights and gauges are notorious for being inaccurate, to the point that they hardly even function. At least rig up a volt meter that you can keep an eye on while driving, for a few days, to verify your alternator is actually outputting the right voltage.

It's your alternator that may be the problem. Your thinking of the battery is wrong because everything on a running car is run off the alternator. Only if the alternator dies will the car continue to run off the battery-but not for long if any accessories are used. So the alternator runs everything AND recharges the battery until it is needed again to start the car.
Your alternator is barely keeping up with running the car, and is not apparently doing much to recharge the battery. Have the alternator tested.

I would not say for certain it is the alternator-there may be a problem in your a/c circuit. But first test the alternator...BTW, Kinsha, pulling off the neg. cable to check an alternator is as old school as me, but on modern electronics it is considered bad practice-electronics don't like little surges or peaks of power. Buy an inexpensive digital multimeter-it is fun learning as you go.

Low battery....you can damage your ecu if you continue to use it. Open the bonnet and charge the battery with a external charger and after charging battery check the alternator whether its charging the battery.

Sounds like a bad alternator. Drained your battery and when you turned on the lights it took all the power left in your battery. When you drain a battery down that far, they are real hard to jump, and coupled with the alternator, the car is not producing enough current to start and stay running.

I would take the alternator off and take it to oyur local auto parts store to be tested. If bad, replace it and charge the battery fully before starting. Then check voltage at battery with motor running. Should be 13.2 -14 Volts DC. If not, you may have a bad battery cable or blown fusible link. (especially that if the alternator tests good).....Mike

This sounds like the output regulator on the alternator! if the car has electronic ignition, this works under load from the engine! if the alternator is not working the the electronic ignition will run off the battery.... thus draining it and the engine will stop! can you test he alternator using a test meter, this should throw out approx' 14-15volts under load! if this is dropping or does not register a voltage then the alternator is at fault! replace and charge battery! hey presto.
hope this helps
Kind regards

does the car start? if it doesnt...then your battery is dead. see if it"ll jump start at least for awhile, if it does and dies again...your alternator could be bad and not charging the battery.

Yes. You also want to check your alternator. Weird as it sounds our electronic dash on a Lincoln had us doing 55mph at a stop. It was the alternator and you may need to check your backup generator for clean power. There is some kind of electronic term regarding "Sine" waves, that apparently matters alot. Good Luck

Try charging the battery or jumping the car, your alternator could be shot and not charging the battery.