Voltage and amps

Addicted4 · Oct 9, 2016

Curious what the obs guys are seeing for volts and amps at an idle? Trying to figure out what my alternator is supposed to put out. My 03 7.3 was 13.4v at a idle but this 95 is 12.1v

old man dave · Oct 10, 2016

Does the voltage increase when you rev up the motor?

Sounds like you are just reading battery voltage now.

crowz · Oct 10, 2016

Should show 13volts or higher at idle.

12.1 is battery voltage only no alternator output.

Addicted4 · Oct 10, 2016

At what rpm does the alternator suppose to charge, if I bring the rpm up the volts increase but not at an idle. Just trying to see if I have an issue or not

crowz · Oct 10, 2016

If its not charging at idle and your idle is correct the alternator is bad.

Addicted4 · Oct 10, 2016

Idles around 600 or so completely stock truck, the volt gauge in the dash is below normal at an idle and once idle comes up it goes up into the normal part of the gauge

Derek@Vision Diesel · Oct 10, 2016

The voltage regulator inside your alternator is failed. You let it idle long enough or with the lights/radio/heater on and it will probably kill it.

It should idle at the same voltage that it drives down the road if the regulator is doing its job.

Addicted4 · Oct 10, 2016

Any good upgraded alternators on the market?

crowz · Oct 10, 2016

Next time mine goes out Im going to find a way to shoe horn the same alternator that's on my 1999 F150 into my F250 superduty. The regulator is replaceable without replacing the alternator and the thing puts out to much voltage when it ages more than to little and killer volts/amps at idle speeds. No clue if I can do it or not but that's the route Im planning on going. My 3600 watt inverter that's in my f150 pulls 160amps max and that alternator handles it just fine at idle.

My superduty alternator which works fine I guess has issues with the glow plugs at idle at times.