Alternator output voltage range

Voltage at the battery when not running needs to be in the 125 range and when idling you need to be between 136 and 144 volts. With the headlamps on and the HVAC blower turned to Hi position charging amperage should be 30 or more amps.

Depending on the load the regulator may put out more than 15vdc but this will be on a very short term basis.

Alternator output voltage range. 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. A reduced output may be a sign that the alternator is failing but the drive belt and wiring should be inspected before replacing the alternator.

For some alternators its normal to see as low as 13 volts. For some a constant 136 volts is an indication of a problem. For others its normal to see as high as 16 volts for long stretches.

Still its perfectly normal for others to see the alternator not charge at all intermittently. Ideally the GM alternator should be putting out anywhere between 135 and 145 volts. A voltage regulator helps regulate the voltage that an alternator provides.

If the voltage dips below the optimal range then the regulator kicks in to get the alternator to make more voltage. The opposite happens when voltage levels read too high. The normal range for most alternators to run is 141vdc.

When the system is run higher than that in the range you are talking about. 15vdc plus it will boil and ultimately ruin the battery. Depending on the load the regulator may put out more than 15vdc but this will be on a very short term basis.

The last number is 135V which is VT or the voltage that the alternator was held at during the test. Since an alternators output can vary both up and down from 135V in real-world situations its actual output limits will vary from the idle and rated numbers. Turn off the car.

Youll want to make sure your engine is off before attaching the voltmeter. Connect the voltmeter to the battery. Place the red lead of the voltmeter to the positive battery terminal and the black.

If the battery reads above 122 volts it has. 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 between 141 VDC and 145 VDC. Set the voltage reading on the multimeter to 20 volts DC direct current The car battery installation and devices all work on 12 volts. There will be no setting for 12 V exactly so set to the next bigger number and that will be 20 volts.

Dont go under that. If the charging system is performing properly the voltage should be between 133 volts DC and 147 volts. If you measure this voltage within this range the charging system is should be working properly.

In the case of an alternator charging at 138 volts this will increase the output voltage to 144 volts. A diode drops a voltage of around 06 volts at low currents increasing up to around 12 volts at high currents. So if we use a diode at low current it will drop just about the right voltage.

My scangauge II is showing 12v to 129 volt output on my alternator. In the winter Im a steady 138 to 141 volts. In warmer summer months in get 132 to 138v.

This voltage will be enough to fully charge or maintain the battery on a trickle charge but charging time will be very long at 138 volts. To fully charge in reasonable times alternator output must be 142 V to 145 V as measured right across the battery posts. Above 145 volts charging voltage batteries have a greatly increased tendency to release excessive acidic vapors hydrogen gas and to corrode things around the battery.

Fixed voltage module set at 148V - 02V Adjustable voltage range from 125-155V - 02V Voltage range from 125-16V - 02V Ford only. Can support up to 4 alternators. Maintain stock battery light functionality.

Engineered and made in USA to OEM standards. Jun 20 2009 Many of the parts stores will do a free charging system test. Voltage at the battery when not running needs to be in the 125 range and when idling you need to be between 136 and 144 volts.

If replacing the battery buy one with a CCA rating at or above 800 and up to 1000 CCA for extra lights winch or what ever. With the battery warning light off standard charging current as measured at the alternator B wire should be 10 amps or less and charging voltage should range between 132 to 148 volts. With the headlamps on and the HVAC blower turned to Hi position charging amperage should be 30 or more amps.

Discussion in 2nd Gen. Tacomas 2005-2015 started by Swwacoma Aug 3 2011. Aug 3 2011 at 335 PM 1 1.

Swwacoma OP Doomsday Squad. ARB CKMA12 Air Compressor High Output On-Board 12V Air Compressor 29001 Genuine Subaru H631SFJ101 Tweeter Kit 1 Pair 9965. As you can see in the above alternator test results the voltage is OK but there is a problem with the current 02amps with no load and a -14amps loaded.

If the test results for the starter or charging systems indicate that there may be a problem you may want to perform the Cable Drop Test to determine if it is due to worn cables or bad connections between the battery and the alternator or starter. To adjust first TURN OFFall nonessential vehicle accessories. Next confirm the battery is in a charged state by using a hand-held digital voltmeter to test voltage at the battery terminals 124V if 12 volt system165V if 16 volt system.

Start the vehicleand adjust system voltage measured at the battery to the desired level.