1963 Dominator with an RM19 3-wire alternator connected as a 2-wire, A-REG One, 12v 6Ah AGM battery, ammeter and BSM, all been working fine for 5 years/12500 miles. The alternator is 9 years/26000 miles old.
Sometimes, after running on green for a while, the BSM turns red and stays like that. After stopping and re-starting, sometimes it's green again, sometimes not.
I've checked the alternator output with a bulb, which lit up with the alternator wire pairings GW/GY or GW/GB, but not GB/GY.
The battery has been tested and pronounced good by the supplier. The voltage is 12v plus, rising to around 14v with the engine running when the charging fault is absent, otherwise there's no rise.
With the fault absent, the regulator output current with the headlight on is about 8A at 2000rpm, falling to 7.2A at 3000rpm and 1A at 600rpm. Is it normal for the output to reach a peak at 2000rpm?
I've checked all the relevant connections, wiggled wires with the engine running, and it makes no difference.
The A-Reg gets quite hot, but that may be normal (I'm not in the habit of fondling it as I ride along).
I appreciate that electronics are generally either working or not, permanently, but in the absence of a loose connection, which I'm so far unable to find, is it possible for the A-REG to have an intermittent fault?
I don't pretend to understand electrics, so I might be missing the obvious. What else should I be checking?
Does sound like an intermi…
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Previously Rob Bradley wro…
It certainly is an intermittent fault.I wondered about bridging the ammeter, I'll give it a try. Its needle does sometimes flick around a lot, more than seems justified by vibration or bumpy roads. I don't know if it's related, or even just imagination, but I get the impression that the BSM intensity varies as well.The charging wiring avoids the PRS8 and is very simple: alternator to A-REG, output from A-REG to ammeter, other side of ammeter back to battery.Battery was load tested by the supplier but I don't know if that would pick up an intermittent internal fault.Other than bridging the ammeter, all I can think of doing now is work through starting from the alternator cleaning and re-making every connection.Previously robert_tuck wrote:
Does sound like an intermittent fault, The battery voltage is good (when charging) , I have not had a battery status monitor on a bike and don't trust them. Check earth connections and I would also bridge the ammeter connections for a while to eliminate it as they can fail. Alternator connectors in gear box area are also vulnerable. Does the charging wiring still go thro the switch as it does not need to. Could have an intermittent short?, Battery could have an intermittent internal fault.
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A by pass wire across the…
A by pass wire across the terminals of the ampmeter of heavy gauge wire will not stop the ampmeter working but will keep the bike going if the ampmeter fails. Earths are another scouce of failure.
Two wires to the battery to a cheap DVM tapped to the tank is good for checking what is going on as is a mate on the back with a meter and various breakout wires taking readings as you ride.
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Intermitant (bad spelling-…
Intermitant (bad spelling-no spell checker!) faults-damn nuisance. If you have this fault and can stop the bike. Do you have lights and can you restart? If so then the Ammeter is in good order, you appear to have just lost the charge from the A reg or alternator. Your tests on the alternator were fine.
If you can decide on a regularity of this intermitnacy (more rubbish spelling) then I am happy to have the A reg back for on the bench testing. All I ask is £5 to cover return postage. aoservices.co.uk
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Does sound like an intermittent fault, The battery voltage is good (when charging) , I have not had a battery status monitor on a bike and don't trust them. Check earth connections and I would also bridge the ampmeter connections for a while to eliminate it as they can fail. Alternator connectors in gear box area are also vulnerable. Does the charging wiring still go thro the switch as it does not need to. Could have an intermittent short?, Battery could have an intermittent internal fault.