Robert : well a capacitor is not a battery. They are here to stabilize the power and to give a constant power. The capacitor doesn't have any energy in it when it is turned off.
Do you have a cd changer or a cd play head unit? If you have a cd player head unit, while cranking the engine, it is normal that the head unit stops because the electronic system shuts off all sources of power to be able to deliver the highest power to the engine. There is a way to bypass this problem. Your radio is connected to the battery thru the iginition key and is only turned on when the ignition key is turned to position 1. Now you have a constant power coming from the battery which is also connected to the head unit but is only used to keep alive the memory of the radio. You can use that cable to power your head unit and you will not have anymore problems with cd playing shutting down etc... (but you will have to shut off the radio manually because it will not shutt of when the key is taken out)

------------------
-------------------------------------
WEB Site : <A HREF="http://www.adamou.dpn.ch
A.S.C." TARGET=_blank>http://www.adamou.dpn.ch
A.S.C.</A> 2000
- Mercedes Benz 560SEC 1986 28.000km BRABUS
-------------------------------------