Do I Have A Problem

[Flash89]

hey i have left my car in my drive way for about a week, went to start didnt start. jump started it let it run for about 20mins or so. turn the car off, about 10mins later went to start it again didnt start, so jumped started it again. checked the volts when the car is running it only 13.5volts, lights on 13.3. when i rev it it stays steady. when the car is off it about 12.5.

the battery is new and the alternator is about 2 years old.

what i got told it should be 14volts when the car is running

and about 12.9 volts when the car is off.

i have recently did a RB26 conversion on my 32

[2LV8ETR]

Go through these steps and see how you go.

Step 1 - Checking Battery

To check a battery surface voltage, remove the positive terminal protective cover. Connect the +positive side meter lead (red) to the positive side battery terminal. Connect the - negative (black) side meter lead to the negative battery terminal. With the vehicle not running and the car sitting over night the battery voltage should be between 12.5 and 12.8 volts.

Step 2 - Checking Alternator Output

Connect the voltage meter lead the same way you would in a battery static voltage check, Start engine (do not drive) at engine idle the voltage should be between 13.6 to 14.3 volts. If not the alternator may need replacing.

Step 3 - Checking Alternator Amperage Output

Testing the amperage output of the alternator is good for measuring the amount (not the level) of voltage the alternator can produce. This test can be tricky because if the alternator is weak it can still show it as producing amperage. Which is good, but if the voltage is low, it will still allow the battery to go dead.

To check the amperage output of a alternator an amp meter is needed. Once the meter is connected start the engine. Next turn on all electrical accessories and raise the engine idle to about 1200 RPM. The alternator should output the max amperage it was designed to produce.

Example: a 90 amp alternator should output about 88 amps.

Note: An alternator can not sustain maximum output for long periods of time. If the alternator is forced to operate at maximum output it will overheat and fail. An alternator is designed to operate at max amperage output only for a reasonable amount of time.

Common Problems:

1. Alternator stops producing electrical power and the car stops because the battery dies.

2. Battery fails do to age or defect.

3. Battery cables become loose causing the electrical system to fail.

[JMW]

Allen is spot on !