Capacitors, do you need them with a battery in the system?

[LSaupe 123]

Troubleshooting an unfortunate loss of charging power.  Always something I guess.  I see in the circuit a capacitor on the high side of the regulator (+) (I am using a Key West regulator).

Is this needed in a system with a battery and/or when using a Key West regulator?   Or... have any of you ran into problems with one installed?  Doubt it would have anything to do with my charging circuit, but thought I would ask.  I dont see them in use for systems with a battery via the following description:

http://www.challengers101.com/RotaxChargeSys.html

Going to check AC voltage (as a function of RPM) on the high side first, and then go from there.  Just odd that one day I have 13.8 Volts, then the next, just battery voltage (12.4).

 

 

[C5Engineer 1170]

Start by checking the output directly at your rectifier. Hopefully it's upstream of that. Check the key west ground too. When mine did that I kept shooting wires until all that was left was the two yellow AC wires coming out of the case. I ended up pulling the motor and changing the stator. It worked one flight and not the next. Not a fun job. Stay positive. I had 75 hrs or better on my bird before I quit having to work on it after every time I flew it. 

Edited 16 Nov 2015 by C5Engineer