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Hi Bob,

You remember that cute ambient temp and voltmeter accessory I found several Christmases ago in Target's $5 gift display? I've never seen another like it, and my daughter never found the second copy of it I'd given her. Its audible alert function recently prevented a roadside assistance call (my son-in-law now has the car for airport and train station commuting) when the brushes finally became too short.

For just a week, I added a cheap ammeter, to gain a slightly new perspective on an intermittent charging trouble I was after. This is something you know I don't recommend, at least not by using the old tech method bringing the entire load and charging current inside the cabin. The wiring needed to do this adds unwarranted fire risk, and in my case, brought me new passengers when I neglected to plug the hole in the firewall after removing it.

My experience watching the ammeter: Despite the unproven calibration, the only way I could ever see it exceed 30A indicated, was to kick the blower on while the lights, rear window defogger and wiper were running, and the car was not. Even then it settled back below 30 discharge after the blower came up to speed.

Of course, the way it was wired, the charge side never saw the total alternator output, only the portion being given back to the battery.

The 200mA reading Joe sees is suspect. This is more like a couple of glove box lamps than any modern memory keep-alive. I'm thinking a double check of the multimeter's accuracy should be made before indicting the radio, as it is pretty common for the meter's shunt resistor to cook sometime during its service. An easy check would be that glove box light - should be 100mA give or take.

I enjoyed your story about the bench testing of your junkyard Bosch. Our yards don't let you bring anything back, save cores, so when I pulled my last alternator, my inspection was limited to eyeballing the slip rings under the regulator. Then it went on the car for final test. I've had two instances of open rotor coils, so I might sneak a continuity tester into the yard next time.