alternator and battery

how will i know if the state charge of the battery is above 13 volts? Also what is a cicuit ? Thank you

You would need a voltage meter to test it.If it was smoking you can count on it being bad,I would suggest putting a new one in since they cannot be brought back to life once the damage is done.The circuit is what I ment(just a type-o) meaning it may not be just an alternator issue.

Thanks....I see you are a mechanic...how much would you charge to put in an alternator?

About $320.00 installed also recommend a Battery charging system test $42.40 for this.