Ammeter

[succor]

Here's another one which is minor but still an issue. I checked the wiring for my headlights all the way to the switch and the wires seem good; however, when I turn my headlights on my ammeter drops down a couple of notches into the red and my dash lights dim also but not blowing the fuse. I don't think this is normal to draw a heavy load like this but I can't trace the problem just yet. My charging voltage drops from 14 volts down to 13.2 volts when doing this. The only thing left to check is from the switch to the fuse block to see if it's shorting out. any other thoughts?

Thanks

 

[Rich Waugh]

No mystery there, it's the alternator. These Chinese tractors have alternators that only put out about 15 amps when the engine is at full RPM. When you turn on all the headlights that's probably about 20+ amps draw, plus the gauges, gauge lights, brake lights, etc. More than the alternator can supply, so the load is put on the battery and thus your system voltage drops to the average of the alternator output and the battery voltage, more or less. There's some voodoo involved with automotive electrics, but that's my understanding of it and it should be reasonably close to accurate.

Some people, including me one of these days soon, change the Chinese alternator out for a Delco 12Si internally regulated alternator with 50-65 amps output. Then you can have all the headlights, additional work lights, etc, running and still charge the battery, too. Search around and you'll find threads on the conversion.

Rich

 

[Bob Rooks]

Rich is correct. The full load output on the OEM alternators is 14 amps. I was dozing on a night job once and my battery went dead in three hours (had all four 55w halogen blazer's going). The OEM alternator is just designed to put back into the battery over a four hour period what was used to start the engine, nothing more. I was one of the guys that switched to the Delco one-wire (12Si-72 amp).

 

[succor]

Thanks, I will do that, you know I just changed it too because the other one failed an realized that 14 amp output is kind of small. I'm also going to check these chinese light switches as well. They apparently have those cheap metal rockers inside them that fall apart because my left right signal doesn't even work plus my hazard switch just broke on the inside.