Alternator, bad? Definitive test?

[ChristopherASA]

I've either a battery problem, or an alternator problem ( guess).


I drive the truck around for a day or two (short trips), and eventually the battery gets to the point where I have to recharge it. Then it's fine for another day or two, and then the cycle begins again. (Battery is about a year old, give or take.)


Of course a friend told me to start the truck and then remove the positive connection to the battery. He said if the engine then conks out, the problem is the alternator. It did. My question is: how definitive is that test?


I'll be reading everything on this forum having to do with "alternator." And I'm watching a couple of YouTube vids in order to learn how to diagnose this problem with a multimeter.

[geezer101]

A basic test is straight forward. Grab a pocket multi meter, set it for V DC and start the engine. Hook the meter onto the battery. If you're getting voltage over 13 volts and it slowly climbs til it reaches 13.6 - 14.1 then the alternator is good. If it is only showing 12.X volts and doesn't maintain voltage, the alternator is dead. Buy an old school hydrometer (the glass turkey baster looking thing that nobody uses anymore) to test the battery's condition as well. They are easy to use and will show you if you have a dead cell in a battery.

[ChristopherASA]

I took a bit ill right after posting my question, so please forgive my delayed "Thank you!"

[geezer101]

:thumbup:No problem. As long as it helped