Is my battery dead?

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keef
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Re: Is my battery dead?

Postby keef » Sun Jul 18, 2021 10:46 pm

Hi Steve,

Thanks very much for your reply.
I will check the charging again as you suggest. I did do this before of course but as you suggest
it's a good idea to go over things again. The diode board was completely replaced with a new unit.
So was the voltage regulator and the battery. The strange thing is that all the changes i have made
have not made the slightest difference to the charge light. It still behaves exactly the same. It is on
as quite a strong red light. It doesn't waver as if there is a dodgy connection.
Anyway thanks again i will go and read it again.

keef

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windmill john
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Re: Is my battery dead?

Postby windmill john » Mon Jul 19, 2021 7:45 am

Hello all,

Unfortunately I am still having this same issue. I.e. my charging light is coming on when riding and staying on. Even revving quite hard will only dim it slightly.

I hope that the connections to the dash lights have not got mixed up and you’re looking at the oil light!! Which may go out if revved hard with little oil!

Probably not this, but had to say.
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keef
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Country of Residence: UK London

Re: Is my battery dead?

Postby keef » Mon Jul 19, 2021 9:08 am

I have not had the dash wiring out for years probably decades so I don't think so.

Thanks anyway,
keef

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Steve Rankin
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Re: Is my battery dead?

Postby Steve Rankin » Mon Jul 19, 2021 10:22 am

Troubleshooting can be a bugger, I give you credit you are going about things in a rational manner.

There used to be a supposedly good book about airhead charging systems and testing them available from Motorrad Electrik. I ordered on a long time ago and never got it, I heard it was out of print, and have had no reply as to when I will get a copy if ever.

I ll be honest, I am just as confused as you are with what is going on with your bike. Sorry mate, I can't give you a hand, a bit too far apart.

I don't know what shape your bike is in so I can't tell what shape the instrument cluster is in where the indicator bulb is. That is one of BMW's problem spots but not so much for constantly on lights rather the opposite, a burned out charging indicator bulb kills the charging system, so does a bad bulb connection in the cluster, they are pretty flimsy. That is not the problem here.I can't see a crossed wire causing the problem unless you or rodents have been working or gnawing on the wires, LOL.

One other weak spot in the airhead charging system is the rotor itself, They tend to break internally and you can find this with a continuity checker, to check, you don't even have to remove the rotor form the bike. Just disconnect the two brush wires and check for continuity between the brushes. Heck, I can't figure a good way to write what I mean. Anyway, this kills two birds with one stone in that you check brush contact, and the rotor for an open state. Of course, this only checks the brushes while the bike is not running so like I said, check the brush springs to be sure they are wound right and at the right tension. I don't know if you unwound them when you changed the brushes but they are a bear to wind back properly, or at least I found that out one time. A loose brush may dance on the rotor slips and not be making contact when the bike is running and be fine when not running.

Anyway, Good luck, Cheers, St.


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