Fri Oct 06, 2017 7:15 pm
#1563746
I have studied the B and C wiring diagram and compared it to the (new) wiring in the Jodel, I can find no obvious difference and yet the low output persists.
A revelation on the B and C website 'FAQ'S is that there is an adjustment screw somewhere on the regulator that will 'up' the output !
Supposedly this is factory set to 13.5 V or so, but maybe mine is set too low? I'll find out tomorrow.
Anyway, what several hours of study has thrown up is that the 'alternator warning' light seems to be no such thing. Opinions required !
It illuminates when the alternator half of the master switch is off (but the 'battery' half has to be on, to provide power to run the light), because a relay is not energised and the bulb is connected through the NC (normally closed) contacts to power and earth. The engine is not runnng at this point so it warns that "no power from alternator" is the case.
So far, so not very clear I'm sure!
Next ,purely to explain how the circuit works if you follow the wiring diagram supplied, the alternator half of the switch is turned on.
The relay is directly energised by this and the NC contacts become open and the bulb is disconnected- and goes out.
It's sort of telling the pilot that there is no problem, that power is being generated, but common sense tells us that it isn't- we haven't started the engine yet.
Ok so far.
Start the engine, - light stays out as power is there from both battery and alternator keeping the relay coil energised.
All good.
Now, imagine the alternator suddenly fails to generate at all for some reason. The light will stay out as it is disconnected all the time that the relay has energy from the battery to keep the relay held open. That relay is tiny and uses virtually no current, when the battery has discharged to the point that it can't keep the coil energised it probably won't be able to illuminate a bulb, it certainly will be totally flat for all practical purposes such as runnng any lights or instruments.
This seems silly to me, surely a bulb that is un-illuminated by the alternator output alone ( if you see what I mean) is the proper thing to have.
As soon as the alternator gives up the ghost a nice yellow bulb illuminates and you still have 100% battery left.
B and C seem to be an excellent firm that make very reliable kit so I'm probably missing something obvious, what is it please ?
A revelation on the B and C website 'FAQ'S is that there is an adjustment screw somewhere on the regulator that will 'up' the output !
Supposedly this is factory set to 13.5 V or so, but maybe mine is set too low? I'll find out tomorrow.
Anyway, what several hours of study has thrown up is that the 'alternator warning' light seems to be no such thing. Opinions required !
It illuminates when the alternator half of the master switch is off (but the 'battery' half has to be on, to provide power to run the light), because a relay is not energised and the bulb is connected through the NC (normally closed) contacts to power and earth. The engine is not runnng at this point so it warns that "no power from alternator" is the case.
So far, so not very clear I'm sure!
Next ,purely to explain how the circuit works if you follow the wiring diagram supplied, the alternator half of the switch is turned on.
The relay is directly energised by this and the NC contacts become open and the bulb is disconnected- and goes out.
It's sort of telling the pilot that there is no problem, that power is being generated, but common sense tells us that it isn't- we haven't started the engine yet.
Ok so far.
Start the engine, - light stays out as power is there from both battery and alternator keeping the relay coil energised.
All good.
Now, imagine the alternator suddenly fails to generate at all for some reason. The light will stay out as it is disconnected all the time that the relay has energy from the battery to keep the relay held open. That relay is tiny and uses virtually no current, when the battery has discharged to the point that it can't keep the coil energised it probably won't be able to illuminate a bulb, it certainly will be totally flat for all practical purposes such as runnng any lights or instruments.
This seems silly to me, surely a bulb that is un-illuminated by the alternator output alone ( if you see what I mean) is the proper thing to have.
As soon as the alternator gives up the ghost a nice yellow bulb illuminates and you still have 100% battery left.
B and C seem to be an excellent firm that make very reliable kit so I'm probably missing something obvious, what is it please ?