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Post by andrejuan on Jul 17, 2022 17:50:08 GMT
Hello Daffers.
Has anyone done an alternator upgrade ?
Mine (on a 66) has always put the needle fractionally into the green area, it is now right on the line and dips into undercharging when the fan kicks in. Presumably it is not "serviceable"? hence the question before I swap it like for like.
TIA
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andrew
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Posts: 1,104
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Post by andrew on Jul 18, 2022 8:11:10 GMT
Your alternator seems to be on the way out, as the voltmeter's pointer should sit in the middle of the green zone when the engine's running. Before condemning it to that "spares store in the sky", you need to to confirm the charging voltage it's producing, which ought to be 14.4 volts, or very near to it. This charging voltage shouldn't change when a load, such as the main beam lights or the heated rear window is switched on.
If the charging voltage is too low the alternator's not up to the job, and needs changing. The alternator and battery are best viewed as a "matched pair". Too big a battery will cause the alternator to over-work and alternatively too powerful an alternator will over-charge the battery. I would fit an alternator of the same design as was fitted to the car when first manufactured, as the Daf engineers and designers no doubt thought long and hard before deciding which one to fit.
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Post by andrejuan on Jul 19, 2022 16:54:53 GMT
Thank you Andrew, I agree that standard is usually the sensible option.
Update.
My (basic) test meter is showing 14+ charge from alternator??? The dash reading is with everything off (just into green). I wonder if it is a gauge calibration anomaly.
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Post by swissdave on Jul 24, 2022 17:28:22 GMT
Thank you Andrew, I agree that standard is usually the sensible option. Update. My (basic) test meter is showing 14+ charge from alternator??? The dash reading is with everything off (just into green). I wonder if it is a gauge calibration anomaly. Gauge I reckon, 13.8 - 14.2V is normal with engine running For reference I use a tiny lightweight alternator off a fork lift truck on my 66 rated really low at 60 amp but works fine despite electric fuel pumps, electric fan etc
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Post by dafman50 on Jul 30, 2022 19:28:07 GMT
I use a 340 one on my own cars seems lot better but remember the gauge is only an indication.
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Post by rhysnolan on Aug 2, 2022 7:56:01 GMT
I have an alternator going spare from a Volvo 340 if wanted.
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Post by andrejuan on Aug 8, 2022 18:49:56 GMT
Thank you.
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liz
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Married
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Post by liz on Aug 15, 2022 12:10:53 GMT
Thank you Andrew, I agree that standard is usually the sensible option. Update. My (basic) test meter is showing 14+ charge from alternator??? The dash reading is with everything off (just into green). I wonder if it is a gauge calibration anomaly. Isn't the voltregulator often to blame? If the thin wiring is worn and torn it looses capacity? Or am I way off? I know in alot of old American cars that's often the case.
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andrew
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Post by andrew on Aug 15, 2022 16:34:02 GMT
The alternator output should be 14.4 volts (or very close to it) so if the dashboard meter is only just in the green I suspect the gauge may be at fault..
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