I have a 2007 Honda Pilot with 152,000 miles. Bought a new battery 3 weeks ago and the voltage is showing 12.6 with the car off. Just put in a remanufactured alternator from Autozone and when I test it under load it only chargers the battery to 13.6 to 13.8. From what I’ve read it should charge to 14.2-14.6. How common is it for remanufactured alternators to be not charge correctly out of the box? I plan to exchange it for a brand new one, not remanufactured, this weekend. Will waiting a few days cause any damage to the car?
So just did some tests to get the actual numbers. Battery with car off is 12.65 volts. Battery with car on and no accessories running is 13.98 volts. Battery with car running and AC, headlights, and radio on is 13.59 volts.
In comparison my Nissan Sentra is 12.57 off, 14.14 no load, and 13.97 with accessories on.
My battery tester says the Nisan is good and the Honda shows either low charging or no output.
If the battery is 12.6 volts is there a minimum voltage the alternator should charge to?
12.6, to 12.7 volts is a fully charged battery (2.1 volts per cell, 6 cells in a battery equals 12.6 volts, not 12 volts). As long as your voltage output is higher than the battery voltage, the battery is being charged. 13.6 to 13.8 volts is normal for a fully charged battery. The alternator needs to output slightly more voltage than the car is using in order to power all of your accessories and keep the battery charged.
is there a minimum voltage the alternator should charge to?
I'm not sure about Hondas.
The documentation for my GMC says:
Fuel Economy Mode
The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 amperes and greater than −8 amperes, and the battery state-of-charge is greater than or equal to 80 percent. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.
and
Voltage Reduction Mode
The BCM will enter Voltage Reduction Mode when the calculated ambient air temperature is above 0°C (32°F). The calculated battery current is less than 1 ampere and greater than −7 amperes, and the generator field duty cycle is less than 99 percent. Its targeted generator output voltage is 12.9 V. The BCM will exit this mode once the criteria are met for Charge Mode.
and it goes on ....
I wouldn't get too hung up on voltages if I were you.
If the car starts every morning, leave it alone.
when I test it under load it only chargers the battery to 13.6 to 13.8.
Perfect. Battery is charging. That's all you need.
From what I’ve read it should charge to 14.2-14.6.
Nope. voltage is managed automatically . It's not supposed to be a steady number.
Keep driving on unless you notice some actual problems.
When I run my topdon battery tester it shows charging low. If the battery is 12.6 volts is there a minimum voltage the alternator should charge to?
If the car starts every morning, leave it alone
Underrated comment.
