Charge/low voltage indicator lamp

[Underwood]

Rotax 912 with Ducati Regulator/rectifier....normaly fitted with a light that comes on when the master switch is engaged and remains on till the engine's generator is producing sufficient voltage then goes off.

on shutdown of the engine the ligght will come back on untill the master is turned off.

 

A quick question to those who have the above with a capacitor across the regulators output, when you switch the master off, does the charge indicator light go off immediately or does it slowly fade out taking a second or 2?

[danny_galaga]

Can you disconnect the capacitor? I don't think the capacitor should affect it, but you are thinking it and that would be the easiest way to know for sure. In any case, it would boil down to something going on with the regulator since it normally wouldn't do this.

[facthunter]

Digital Battery Chargers do that. Nev

[skippydiesel]

On 18/05/2025 at 5:41 AM, Underwood said:

A quick question to those who have the above with a capacitor across the regulators output, when you switch the master off, does the charge indicator light go off immediately or does it slowly fade out taking a second or 2?

FYI - Just in case you assume that Rotax/Ducati VR + Capacitor system are all fitted with a red operating light; my last & current aircraft do not have this feature 😈

[danny_galaga]

13 hours ago, skippydiesel said:

FYI - Just in case you assume that Rotax/Ducati VR + Capacitor system are all fitted with a red operating light; my last & current aircraft do not have this feature 😈

Yes, I don't think it's actually needed. Unlike 3 phase car alternators, where from my very shaky memory, the warning light goes through the exciter diodes, which gets the rotor windings going until the alternator outputs energy. If the warning light blew in that case, your car alternator might not start charging. But the joys and wonders of electrical engineering - quite often there's enough residential magnetism in the rotor to get everything going regardless. Usually after a big rev. 

 

Anyway, that doesn't help the op 😄