Nah with his experience and his unfaltering verbosity and precision I'm pretty sure he's wired his brain directly to a USB interface.

 

Touché

 

Actually a failed battery from my experience is the leading cause of this. The alternator runs a high amp rate of charge constantly. And the hv spikes a lot more causing failure on rare occasion. Usually when there is a poor connection from one of the terminals

Also it depends on what type of alternator you have. Many of the more modern alternators use what they call a charged field coil. In other words the alternator will not produce any charge unless it has battery voltage present to charge the magnetic field. Actually this type of system was used in the 70s also. Kinda like FI. And it runs most of our FI systems today. correction, if I remember right their are two types of battery powered alternators. One charges a rotor and creates a magnetic field. The other charges the field coil. I believe the later is what we have today. The old ones charged the rotor I know for certain. Anyways....

I can tell you have knowledge in this area. So that is great. Its always profitable to discuss things in a civil manner.

Unlike some of the others who have no idea but place arguments anyways. Right odgreen89on35s?


In regards to this thread. I don't believe the cherokee alternator is capable of charging without another good battery present. But I have not put it to the test yet.

 

It wouldn't stay at that voltage. The initial spike might damage electronics, so you should disconnect the leads first, but it wouldn't hurt the battery.

 

As long as helps someone, I don't consider it time wasted.

(And yes, I do type this out. I wish I had a USB interface to my head - the direct connection to the computer would be nice, and I'd love to have direct access to diagnostic information...

 

JDB-I (Jon-Board Diagnostics)?

We're halfway there. Guy my parents used to work with was a lumberjack until a tree landed on him. He's got an implanted computer that manages his spine to regulate pain, motor control, and regular sensation with minimal drugs. Research for blindies is quite advanced, too.

 

Look up the "C-leg" - got a buddy down in Oz that has one, and it's impressive!

Sounds like they've cranked up the capabilities on the pain pumps as well (I sometimes wonder if I don't need one anymore, with everything I've got that hurts...) beyond just giving you a hit of morphine & fentanyl...

 

Learned a little bit more about alternators this weekend. Since an alternator does not have fixed magnets like a dc motor, it uses electromagnets (main difference between an AC motor and DC motor) instead. On the alternator, it needs voltage coming into it from the battery to create the magnetic field to use it for power generation. So if the battery wasn't there, technically the vehicle wouldn't run. That's just what I picked up from some guys who have electrical engineering degrees while we were huddled around a '52 *****'s resto project.

 

Exactly. This is why you need a full battery to correctly test alternator output. Have to make certain the field is fully powered.

 

I thought I'd referred to that, when I'd said you need to feed power into the field to get an output? Anyhow.

Once the vehicle is running, it will run fine on the alternator - it feeds itself a trickle from the system via the regulator. This doesn't violate anything, since it's a device to convert kinetic/mechanical energy to electrical energy, which means it's converting engine output to electrical output.

The electrical field is first supplied by the battery - but that's only a few seconds. Once the engine is running, the regulator/field feed is provided by the alternator itself (the output is tapped to provide the field input.)