I've just changed the alternator on my car and the volts light goes on when i accelerate, why?

when i accelerate my volts light starts to flicker, and when i go above 25mph it stays on. ot times when i stop for a light the volts light will go out, then back on when i accelerate.
I've just changed the alternator on my car and the volts light goes on when i accelerate, why?
Could be numerous things, bad battery, bad cables, loose connections, defective alternator, your best bet is to take it to a reputable repair facility for a proper diagnosis rather than throwing parts at it hoping for a cheap fix.
I've just changed the alternator on my car and the volts light goes on when i accelerate, why?
your belt isnt tight.



Tighten it up, should stop doing that.



When you accelerate, the belt slips more.
probably a faulty alternator, could also be a faulty voltage regulator (depending on the year/make/model of your vehicle)



Even new in box parts can be junk. Always have the parts store test the new items before you leave.
Sounds like a defective part. If you replaced the alternator with one that puts out more amps than the original, your cars electrical system is trying to prevent an overload into the car. A safety device you could say to protect it from being fried.
Your serpentine belt is loose. Get a new one.
I agree with Dave on this one but here is a hint advance auto parts has nothing but rebuilt alts. and starters I would in the future have it tested before leaving the store plus if your belt was loose it would squeal loudly when lights and accessories were on but it's always good to put a new belt on when changing the alt that way you could keep an emergency spare belt in the trunk in case of need I do and i have not regretted it.. ps im not knocking advance auto they really do have great parts but some not tested..
It sounds like your charging system is operating wide open all of the time. Use a voltmeter to check the voltage at the battery while the car is running. The voltage should be between 12.5V-14.5V. Then, see what it is when the engine RPMs are around 2500. If it goes above 14.5V, your voltage regulator or related circuit wiring is to blame.
It's sounds like you belt is slipping or glazed. Or maybe you just didn;t tighten it enough.