Properly Checking Alternator Amperage

[Blind Driver2]

My 7.3 has been turning over a bit slower over time and won't turn over as long. Batteries, cables, and starter are new as of last year.

The local auto parts store tested my alternator. It had 14.12 volts and 50 amps at idle with all accessories running. This doesn't seem to be a very good test.

Without taking the alternator off, what else can be done to determine if I'm getting all the available amperage. I have the Leece-Naville and should be able to easily charge both batteries.

 

[icanfixall]

Thats to low on the amps. Sad to say it but your alternater is worn out. A little information about alternaters to share. They have two jobs... One is to refill the batteries with the power just used to run the starter. Now once the engine is running this happens easily. Then the second job iit does is it runs all the electrical things in the car or truck.. Your not running off the battery to listen to the radio or use the headlites off the battery. Everything electrical is run off the alternater. Now don'r even start thinging you can charge up a completely dead battery.. They will heat up and not live as long doing that.. The magically let out the smoke from the mysterious hidden smoke container ......

 

[riotwarrior]

In order to properly test the alternators output there is a way with specialized gear to load it down and see what level of current it can deliver and at what voltage.

I have one of the testers to determine that through a load test and I can load to 500 amps if need be.

I'll try to locate my file on using a battery/starter/alternator tester and upload it.

This is similar to what I have, just a different brand

You must be registered for see images attach

You may find this to be useful info too btw there is quite a bit on testing battery charging system and so forth....just saying...

http://www.prestolite.com/pgs_training/training_2.php

JM2CW

Al

 

[kc0stp]

1g or 3g alternator? If its 1G thats about right at idle as their rated at 70amps at 2000rpm however as stated above the only way to truly test an alternator is to take it off and put it under load beyond that all you can do is load it up and see if voltage drops.

 

[riotwarrior]

.....I have the Leece-Naville and should be able to easily charge both batteries.

1g or 3g alternator? If its 1G thats about right at idle as their rated at 70amps at 2000rpm however as stated above the only way to truly test an alternator is to take it off and put it under load beyond that all you can do is load it up and see if voltage drops.

The answer to your question was clearly indicated in his thread....

 

[Blind Driver2]

I had two bad batteries

I bought both from O'Reilley's in May of 2011. They are only 1 1/2 years old. I never suspected them. I normally go 4-6 years b efore needing to replace a battery. I replaced two bad glow plugs earlier in the week. I'm looking forward to 20* weather just to see how it'll start with my wmo blend