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Charging issues

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M0WBY:
Hi

I am having charging issues.

So far I have replaced both parts of the alternator with good second hand parts that were fully tested before putting them on. At the moment it is charging I think. At tickover it has 12.4v across the battery. At 2.5k rpm it has 14V across the battery. At 5k rpm it has 14.8V across the battery. The battery seems to be charging. If I take the battery off the bike and charge it up overnight using my Optimate it charges and if left it stays charged up.

However when switch the lights on it drops a full volt and at tickover it only reads 11.4 across the battery. When switched off and back on again the battery behaves as thought it has dumped all it's power and won't hardly turn over. But if it is left for half an hour or so seems to recover. It does not do this with the lights off and behaves as though it is fully charged.

I don't know what to replace next. I am assuming the reg/rec is ok as it never goes above 14.8v and the manual says as long as it is under 15v it is ok.

I may replace the battery but it is less than a year old!

I don't know why the lights seem to run the battery flat so quickly.

Thanks for any help.

Cheers

John

 >:(

SteveD CB500K0:
Your charging voltages are spot on. I suspect that your battery is dead.


Sent from my iPhone using Tapatalk 2

Bryanj:
With the lights on the engine needs to be over 3,500 rpm just to break even

M0WBY:
Hi

So the battery has to hold a pretty good charge or in stop start traffic with the lights on it would go flat pretty quick requiring a jump start if it cut out for any reason?

Are Honda electrics really that crap?

I still think my battery is duff... I hope so anyway or my bike is getting traded in at the soonest opportunity.

Cheers

John

SteveD CB500K0:
In the 70's, motorcycle charging systems (in general) were pretty crap - mainly because they couldn't build small, light, powerful generators like they can today.

With the lights on, no Honda of that age will charge at below about 3500 revs (as Bryan says). There's a revs vs charge table somewhere on .net - I'll see if I can find it.

So if you ride with your lights on and in stop/start traffic, your battery will run down.

If the battery is less than 100% it will go flat really quickly!

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