"alternators and the old ones are rebuilt n sold for 3x the profit. "

My cousin used to rebuild his own. (we are/were a car family) Before the days of the built in regulator all you had to do was change the brushes and clean the armature (is that the right word ? been a long time) and you were done. You knew if the diodes were shorted because there would be smoke. It was very rare for the diodes to go bad. There was some kind of trick to holding the brushes in for reassembly, paper clips through some holes.

I knew a hillbilly mechanic who had a quick test, when it is charging there is a noticeable magnetic field right at the back of the alternator where the shaft is. Just took a wrench to it, if it pulls there is field current. If there is field current and no smoke, 99 % of the time it is charging, or at least working. Because of regulation that field will be strongest at idle.

Also, older cars charged at about 14.4 volts. Any more and you had to keep putting water in the battery. The newer cars with their complex electrical system pulling alot more and the sealed batteries you want to see them charging at least at 15.2 volts. Some newer cars actually pull more current to run than to start.

"this in reality doesn't cover radio esp 400 watt rig/lights/AC in slow go commuting with extensive idle...in cold weather. That 120 doesn't charge the batt "

I am surprised more people do not have problems when forced to dive in rush hour traffic, err actually I mean park in rush hour traffic on the highway.. I used to work cross town and 23 miles frequently took me an hour to get home. After an incident I told them I was not going to be in a rush to get there, and I got a raise to make up for it but the quit time was always the same. I tried to convince them to stay open another hour or two but they did not want to do it. So I left a five. Then I got into the habit of stopping at a local bar out there to kill that hour and I got home at almost the same time.

But they really have beefed down the alternators in cars. It is so bad that they have in the instructions "DO NOT INSTALL THIS IN A CAR WITH A DEAD BATTERY". It cannot handle a dead battery like in the old days. Hell we used to just change of fix the alternator, jump start the car and let it run for a twelve pack of beer then it was fine. Can't do that no mo.

That is because the bean counters now outrank the engineers. Let's put it this way, my sister is throwing out a three year old refrigerator. Realize that the 30 year old refrigerators are mostly still running.

Yup, Dodge v Ford was the worst thing to happen to this country. But then I imagine it is the same all over. If you could find companies that are not publicly traded you might get quality product, but nobody wants to use their own money for startup. Plus they ALSO want to make as much money as possible for the least work possible.

So we got what we got.