Charging systemUp to Commando
Charging systemPosted by ray_robson at August 05. 2010
Could anyone please advise how I should test the charging system on my 850 MkIII,
with regard to alternator output and rectifier, zener diode operation
Re: Charging systemPosted by Tony Ripley at August 06. 2010
A couple of questions first, are you trying to diagnose a dead system or do you just have doubts that the system is working as well as it should do ?
The prodcedure will be somewhat different.
Secondly, do you have access to a meter that can go up to 5 amps or so (and obviously 15 volts or so ).
Assuming that it works but just not as well as you think it should:-
It is actually not easy to check individual bits of the charging system without an understanding of zener diodes and bridge rectifiers but as a starting point the simplest thing to do is remove the black thin black wire going to the battery (not the thick black one going between the battery and the starter solenoid) connect the meter on the 10 Amp range ( if you have it, but at least 5Amps) in between the thin black wire and where you removed it from the battery.
Turn the ignition on and gently turn the engine over, at some point you should see a discharge of a couple of amps depending on contact breaker of electronic ignition. This proves you have things correctly corrected. Now start the bike you will find that just a little over tickover, you are now in a positive state.
Now turn the headlights on, meter will now show discharge of say 5 amps. Now bring the revs up and you should find that before you get to 3000 RPM you are back in a positive state. If this is the case and then any further revs give you a higher current (this will very much depend on the state of charge of the battery) then the charging system is probably OK.
If you do not get equilibrium before 3000RPM with the headlight on then you have a problem but lets go one step at a time.
Let me know how it goes.
Re: Charging systemPosted by ray_robson at August 07. 2010
A basic health check on the electrics was the task, as the bike has been idle for about twenty years, I just wanted to make sure everything operated as it should. Maybe it's because I'm belt and braces sort that I'm looking for problems that dont exist !
Once again, many thanks