While riding on Wednesday experienced major probs when turning lights on. Misfires etc. battery read 12.4v when I got back. Charged up for 36 hours. Read 12.8. This morning read 12.4 again. Started bike to check voltage under charge and multimeter was going mad. Flashing digits all over the place. Managed to decipher ranges in V from 12 to 18. Very rapid flashing so hard to make out. Any clues fellow members?
Assuming you still have a…
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That battery doesn't soun…
That battery doesn't sound that great to me. How old is it?
Be aware that cheapish digital multimeter's will give spurious readings from Commando electrics when the engine is running as there can be a lot of spikes. I have a cheap one that says my charging system is at 18volts when engine is running. My expensive Fluke Meter registers more realistic readings.Ideally you need an old fashioned moving coil Meter with a needle to get an accurate reading.
Ian
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Previously ian_goodhall wr…
Previously ian_goodhall wrote:
That battery doesn't sound that great to me. How old is it?
Be aware that cheapish digital multimeter's will give spurious readings from Commando electrics when the engine is running as there can be a lot of spikes. I have a cheap one that says my charging system is at 18volts when engine is running. My expensive Fluke Meter registers more realistic readings.Ideally you need an old fashioned moving coil Meter with a needle to get an accurate reading.
Ian
Thanks Ian. Battery is only 2 years old. Last year I checked the charging with my meter and got steady readings around 13.8v. I will check output at alternator then at the rectifier. I have a spare rectifier and zener diode so will check using replacement. Will keep you all posted.
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Assuming you still have a zener diode or diodes (Mk3) it is likely the culprit. Mine went to 16v and gassed the battery regularly so I fitted an electronic reg from Paul Goff. 12.8v is normal after charging and will 'float' off after a while. 12.4v might be a little low but depends on accuracy of the voltmeter. Try and get an analogue meter on it and you'll have a better idea but my bet is the zener. Let us know.