C3 Charging circuit diagram please Marc :)

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MikeT
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Re: C3 Charging circuit diagram please Marc :)

Post by MikeT » 08 Oct 2018, 16:19

PM sent, Marc

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MikeT
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Re: C3 Charging circuit diagram please Marc :)

Post by MikeT » 09 Oct 2018, 16:59

Last night, in the C5 I queried Lexia for a BSI parameter "Alternator Excitation Voltage" which clearly showed 0V engine off and 14.4v engine running.

The C3's insurance kicked in at midnight so got it taxed at lunchtime at a hefty cost of £20 :D

Its' battery had consumed a lot of watts on charge overnight (I think this is a cracking battery for it's size!) and after reffiting, I consulted Lexia to compare the above Excitation Voltage reading.

It showed ~5V engine off and ~6V engine running but still the alternator did not start charging (yet ECO-MODE went off!) until rpms exceeded 3K (a little llower than last time).
While driving, excitation voltage was stable around 7V.

After a bit of driving fun and punishment, I stopped for refreshment and interrogated the BSI again. Values were the same except this time after starting, I didn't rev it but just pulled away sedately. The next time I looked at the Live Voltage data (as I changed up to second gear and sure I hadn't exceeded much over 2krpm if at all) I noticed the alternator had kicked in. Quirky or what?!

I've ordered one of those voltmeters for the ciggy lighter so I can more conveniently keep an eye on voltages.

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MikeT
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Re: C3 Charging circuit diagram please Marc :)

Post by MikeT » 20 Oct 2018, 18:54

Having had the ciggy lighter voltmeter to monitor I'm still no closer to a diagnosis. I have to rev the engine to get it charging as expected.
But what's with the excitation voltage wire only showing 6-7 volts (while on the C5 is battery voltage)?

Would it be ok to disconnect the BSI signal wire and supply battery voltage to the alternator as a test to see if it "excites" at idle speed?