11
Oct
Maybe like a desulfating battery charger. The A connector should have 3 wires.
Can overcharging alternator kill battery.
Alternator putting out 15 volts. Is 15 volts too high for alternator. Higher than 15 volts indicates a fault in the charging systems voltage regulator or related circuits. If its substantially excessive this can cause electrical system andor battery damage.
You mentioned your voltmeter runs at about 15 volts most of the time. Can overcharging alternator kill battery. Why is my alternator putting out 15 volts.
Higher than 15 volts indicates a fault in the charging systems voltage regulator or related circuits. If its substantially excessive this can cause electrical system andor battery damage. You mentioned your voltmeter runs at about 15 volts.
Mar 8 2016. Lately my alternator began charging at 15 volts. I replaced the alternator checked all the wiring checked every ground under the hood and everything seems fine but it still overcharges.
Reading 152 without a load and 158 to 16 with a load but never goes any higher. Provided your alternator is wired correctly it is unlikely you will see 15volts continuous. There are a full range of regulators available for different makemodel alternators.
But I know of none that are set at 15volts. Most 12Volt regulators are designed to regulate between 142 to 147 volts. I did notice however that it was charging at 152 ish volts and so I was a bit worried but after letting it idle for 15 or so minutes checking the voltage periodically it went down to 148 volts and stayed there.
I think maybe the alternator intentionally volts it past 15 for a short burst sometimes. Maybe like a desulfating battery charger. That depends on the application use of the alternator.
Forautomotive applications NO 15 Volts DC is not too much. Generally an acceptable voltage output range for. Normal output for an alternator is 14 to 145 volts.
Check the output at the alternator if it is greater than 15 volts the alternator voltage regulator is bad. Often these are in the alternator and its easy to swap out the alternator. Otherwise it needs to be essentially rebuilt.
Normal charging on these is 145 to 15 volt any meter could vary enough to get the 152. These charge heavier than the old days of 135 -14. Old battery may have been the problem but one thing for sure if battery dead try to charge it up as these put out so much charge they commonly toast alt trying to bring up a dead battery.
And then measure what voltage is coming out of the alternator power output and what is going into the A terminal. If it is more than 3v lower then find where this drop is occuring. If the A terminal was rewired to the big bolt lug on the starter relay then these voltage drops would be eliminated.
Clean the battery poles. Over time a thin oxidized coat forms on the battery poles. Disconnect the battery terminals and clean them with some sandpaper or a small file.
This will ensure that the vital connection from the alternator to the battery is in good condition. An alternator should put out between 135 and 15 volts of power. The alternator should be tested with the engine idling and electrical accessories such as the radio and headlights turned off.
How do you know voltage regulator is bad. If you dont see the recommended voltage when you check charging voltage at the battery with the engine idling check the wiring connections at the alternator not just visually or by wiggling the wires or connectors but checking for excessive resistance by doing a voltage drop test. Many so-called alternator problems turn out to be nothing more than a bad connection at the alternator or a bad.
Normal Output An alternator should put out between 135 and 15 volts of power. The alternator should be tested with the engine idling and electrical accessories such as the radio and headlights turned off. Good alternators measure the voltage at the battery terminals and use whatever voltage at the alternator that is required to obtain good voltage at the battery terminals.
So as a summary you should be measuring the voltage at the battery terminals. There the voltage should be. Trying to figure out an alternator overcharging issue.
Had overcharging issue and replaced alternator after mechanic said issue was internal voltage regulator. Also put in new battery at that time as. Idles around 152 volts and highway it gets up to 157 or so.
Oddly enough battery doesnt seem to get hot even after. This is easy to test but you need a multimeter. Connect the multimeter to the battery and run the engine at a fast idle say 2000 rpm.
You should get a voltage reading anywhere from 14 to 15 volts if the battery is fully charged and the alternator is working. If the reading is around 12 volts then the alternator is not working. If the voltage stays at 155 volts after the cars been running awhile your battery could have a shorting cell therefore its bad.
If your battery tests good your regulator circuitry isnt functioning properly. If you have an external voltage regulator try replacing it. That all seems pretty straightforward.
But the dealer wants to replace the alternator too claiming that is it putting out 15 volts instead of the expected 145. 1K In searching I cant find a single instance on this board of alternator problems. Should I get a second opinion.
Battery voltage may be fine but I bet the cranking amps are not even close. Replace the battery and the alternator will settle down to the 147 Charging volts. 11 people found this helpful.
I had the battery replaced by AAA yesterday. Today is when I noticed the 152 volts. From what I can see the alternator output voltage to the battery should always be less than 15 volts with engine rpm under 2000 rpm.
Another test you could try there should be an A connector and a B connector on the alternator. The A connector should have 3 wires. Its putting out 153v when the car is running and under load it is putting out 151v it is suppose to be at around 14v.
The mechanic told me my alternator needs to be replaced but why would it put out to much voltage. Is this why my battery wont recharge correctly. I thought when a alternator needs to be replaced it puts out not enough voltage.
Anything between 138 volts and 15 volts is safe. My wifes 76 LTD carried 148 volts for over 20 years. Only ever replaced 3 batteries.
Sent it to the crusher about 5 years ago. Still using the battery. Light bulbs burning out was a bit of a problem but the ham radio equipment loved the higher voltage.
I have a 2006 Buick LaCrosse with the 38 L motor. Last week I found out that the alternator was overcharging charging at around 155-157 volts The car has 72000 miles on it. I replaced the alternator with one that I got from a salvage yard to save money but it is still over charging at the same voltage.