Greetings,
My 66 CA78 has charging problems. If I leave the headlamp off, I can go for a couple of weeks (weekend rides) without recharging. With the headlamp on, after a few hours of riding the battery is flat. Here's what I have:
Battery: 3 years old, 12.5 VDC after trickle charge to full.
Alternator: Pink to Brown=0.5 ohms, Pink to Yellow=2.1 ohms, Yellow to Brown 1.3 ohms, All colors to ground= infinite ohms.
Rectifier = Rectron 50A/1000V bridge. Measured 12-15 VAC going in from alternator, rpm dependant. 8.5VDC going out out to the battery (Headlamp off). Seems like the bridge is working correctly.
So, to get 14.5 VDC to charge the battery from the rectifier, I need 14.5VAC/0.707=20.5VAC coming from the alternator, which I am not close to getting.
Any thoughts?
Low alternator voltage output question
The measured voltage drop from your rectifier seems a little suspicious. I would expect no more than about 2 volts difference between the AC volts RMS input and the DC output. Do you have another rectifier you could try, perhaps the OEM unit? Have you measured with another meter just to confirm your results? Aside from that, Is it possible your battery is defective like maybe a cell is beginning to short resulting in an impossible load for the alternator? Finally, could there be something drawing too much current on the system such as a bad ignition coil or an aftermarket coil with too low primary resistance? Bulb wattages are also a concern too with these older bikes, but it appears your problem is present without the lights on. That's just my immediate thoughts. Let us know what you find out.
"If the women don't find you handsome, they should at least find you handy." Red Green
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