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| | | | Joined: Nov 2010 Posts: 339 Shop Shark | | Shop Shark Joined: Nov 2010 Posts: 339 | When I turn my head lights on, engine running at about 1800 rpm, the ammeter goes to discharge. I am running an alt., not a one wire one, the ammeter should go to the plus side I would think at that rpm, what is going on? 53 3100 root | | | | | Joined: Mar 2010 Posts: 10,270 Renaissance Man | | Renaissance Man Joined: Mar 2010 Posts: 10,270 | Can you set the RPM to 1800 with the throttle cable, with the lights on, in the driveway, then check the voltage at the battery?
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
| | | | | Joined: Aug 2005 Posts: 6,377 Ex Hall Monitor | | Ex Hall Monitor Joined: Aug 2005 Posts: 6,377 | What is the output of your alternator? I put a 60 amp 6v alternator on my '38 and after about a month the ammeter started showing a discharge under any load. A check with the voltmeter shows it's charging just fine. I'm assuming the higher than it was designed for current toasted the ammeter. After a hot start the ammeter would show full charge as the alternator was shooting 60 amps through it & it was designed for ~30 amps max. I put a 6v voltmeter under the dash and just learned to ignore the ammeter.
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| | | | | Joined: Feb 2004 Posts: 29,743 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,743 | That dash-mounted ammeter is about as accurate as doing trim carpentry with a double-bit ax. Measure the voltage at fast idle at the battery posts with high beam headlights and/or other loads running such as the heater fan, and see if the voltage is 13 or more. If so, install a different ammeter or get that one reconditioned.
Jerry
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| | | | | Joined: Jan 2015 Posts: 914 'Bolter | | 'Bolter Joined: Jan 2015 Posts: 914 | Is the truck a 6v or 12v originally?
Did you switch over to a 12v AC generator?
Is that still the origianl 6v amp meter?
| | | | | Joined: Nov 2010 Posts: 339 Shop Shark | | Shop Shark Joined: Nov 2010 Posts: 339 | 12V, complete all new wires, 12V 63 amp. alt. new gauges everything new. Have not checked battery but it it new also. root | | | | | Joined: Mar 2010 Posts: 10,270 Renaissance Man | | Renaissance Man Joined: Mar 2010 Posts: 10,270 | Checking voltage at the battery while the engine is at 1800 RPM is not for testing the condition of the battery, but rather, to check if the charging system is putting out at least 13.5 volts at the battery.
Carl
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
| | | | | Joined: Nov 2010 Posts: 339 Shop Shark | | Shop Shark Joined: Nov 2010 Posts: 339 | The amp. meter is reconditioned and checked before install, was good. I have not checked the output of the alt. but that is next. Went for a drive today for the first time in three years. Drove OK but need to get the front end aligned and tighten up the steering a little. Also get a tail pipe on it. Thanks everyone for the good info. root | | |
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