2001 Lexus ES300 Q&A

2001 Lexus ES300 Question: What voltage should the alternator put out at idle? What voltage when reved up?

I'm getting 13.6 volts at idle but when I rev the engine the volts drop below 13 volts. The battery may be bad as it only reads 10 volts with engine off. -
Answer 1
Have the battery tested both with a hydrometer and high rate discharge test to see if it is good (probably not. At rest voltage for a fully charged "good" battery is 12.6 volts an alternator that is charging will read 14.6 approx across the battery with the engine running. also take a reading at the large B+ alternator terminal and see if the voltage is higher there indicating bad connections. -