What is a good range for alternator output?
September 22nd, 2016, 2:08 PM
#1
What is a good range for alternator output?
Hi all, I got to playing around with my innova 3610e OBD2 scanner. I saw in the menu that there are menu options to test the battery and alternator. I ran the alternator test, followed the instructions on screen which were to turn engine on, then turn on headlights and rev and hold till RPMs are at 2000, and then it wants you to hold that for 20 secs then it does its analysis. I did the test twice, and both times it said that the output voltage was too high and to check the charging system for causes. The first result was 14.96V and the second time it was 14.94.
I do have dual batteries, and I'm not sure if that fools the car's ECU to output more voltage if both batts are low. Is this a sign of an alternator possibly on its last legs? Maybe this is why one of my Optima yellow tops has a crack in the case near the neg. terminal and is slowly leaking electrolyte, b/c the alternator is over charging the batteries? My 2nd batt doesn't have any signs of cracks or bulging. Never had an issue with the charging system ever or the batteries since I put in dual batts about 5.5 years ago. Its a 07 Tahoe LTZ, I believe I have the 160 amp alternator. I do not have a battery isolator installed.
I just went outside and checked the voltage on the batteries with engine on at idle, main batt. was floating around 14.8V-14.9V (this is battery with crack in the case near the neg. terminal); 2nd battery was floating around 14.6V-14.7V. Then I had my wife rev and hold the motor at 2000 rpms, and checked the voltage again, and this time both batteries were floating around the same voltage, 14.6V-14.7V. Not sure why the discrepancy on the main battery from idle to 2000 rpms? maybe something to do with equalization between the two batts?
Any input is appreciated! oh btw, I am replacing both batts today, my dual Odyssey batteries (48-720) are arriving today. I am replacing due to the crack in the main battery.
I do have dual batteries, and I'm not sure if that fools the car's ECU to output more voltage if both batts are low. Is this a sign of an alternator possibly on its last legs? Maybe this is why one of my Optima yellow tops has a crack in the case near the neg. terminal and is slowly leaking electrolyte, b/c the alternator is over charging the batteries? My 2nd batt doesn't have any signs of cracks or bulging. Never had an issue with the charging system ever or the batteries since I put in dual batts about 5.5 years ago. Its a 07 Tahoe LTZ, I believe I have the 160 amp alternator. I do not have a battery isolator installed.
I just went outside and checked the voltage on the batteries with engine on at idle, main batt. was floating around 14.8V-14.9V (this is battery with crack in the case near the neg. terminal); 2nd battery was floating around 14.6V-14.7V. Then I had my wife rev and hold the motor at 2000 rpms, and checked the voltage again, and this time both batteries were floating around the same voltage, 14.6V-14.7V. Not sure why the discrepancy on the main battery from idle to 2000 rpms? maybe something to do with equalization between the two batts?
Any input is appreciated! oh btw, I am replacing both batts today, my dual Odyssey batteries (48-720) are arriving today. I am replacing due to the crack in the main battery.
September 22nd, 2016, 6:38 PM
#2
the vehicle has multiple charging modes as it is ecm controlled.
15 volts output corresponds to a 80% charge output. It will not hurt a lead acid battery. As long as your under 15.5 your ok.
As long as you don't run an agm battery. Most production vehicles that run a agm battery require a intelligent battery sensor to drop output voltage to nmt 14.4
15 volts output corresponds to a 80% charge output. It will not hurt a lead acid battery. As long as your under 15.5 your ok.
As long as you don't run an agm battery. Most production vehicles that run a agm battery require a intelligent battery sensor to drop output voltage to nmt 14.4
September 25th, 2016, 2:03 PM
#3
the vehicle has multiple charging modes as it is ecm controlled.
15 volts output corresponds to a 80% charge output. It will not hurt a lead acid battery. As long as your under 15.5 your ok.
As long as you don't run an agm battery. Most production vehicles that run a agm battery require a intelligent battery sensor to drop output voltage to nmt 14.4
15 volts output corresponds to a 80% charge output. It will not hurt a lead acid battery. As long as your under 15.5 your ok.
As long as you don't run an agm battery. Most production vehicles that run a agm battery require a intelligent battery sensor to drop output voltage to nmt 14.4
I have two worries now, the first one, before I put in the new Odysseys, I charged them with a batt charger, probably didn't need it, but wanted to anyways, and I checked on the 2nd battery while it was charging (first battery had already been charged up by me) and the charger out put was at 15.1V, then I kinda freaked out, b/c I was worried I just did most incorrect thing on a new battery. 2nd, if the alternator output does the same voltage, 15+ then I'm just slowly ruining these expensive batteries, lol.
geez louise!
I guess there's nothing I can do about it now, right? Thanks tech2!
Last edited by Typerod; September 25th, 2016 at 3:59 PM.
