Nasty squelch/static/sub pop with ignition on

[jimidemo]

So what had happened was....Changed my #2 battery on Friday night then wanted to test everything for our lake trip Saturday. When I turned on the ignition all seemed well for a moment....then it all went dead. With ignition in on position it beat my sub and squelched awefully. Immediately checked grounds at battery and realized there was a third ground which got hidden behind battery during install. Never turned on stereo toggle switch at all during this testing. Hooked up battery ground and it fired right up on the fake-a-lake.

Saturday at lake with engine on and stereo toggle on the squelch and static were back. Tured it right off and just figured I'd troubleshoot later. The odd thing is when we parked and with thie ignition off but stereo toggle on tunes were good. Any ideas an what to check would be appreciated.

Thanks....

[chpthril]

Whar was the need for changing batteries?

Has anything been changed, added, modified in regards to the stereo or battery setup, prior to the last trip out that all worked as designed?

Stereo sounds normal with engine off, but acts up with engine running. Describe your dual battery setup and how the amps and stereo are wired..

[jimidemo]

Changed one battery. Battery was old and no longer held a charge. Perko dual switch. No problems existed prior to event. Ran on battery one which was the same battery as last trip. As far as how it's ran l'll have to get back to you. Is there something I blew upstream?

[chpthril]

I would double and triple check the battery wiring. Next, check the static battery voltage and engine running alternator output.

[jimidemo]

Will do. Thanks. That'll getr me going for now

[chpthril]

Changed one battery. Battery was old and no longer held a charge. Perko dual switch. No problems existed prior to event. Ran on battery one which was the same battery as last trip. As far as how it's ran l'll have to get back to you. Is there something I blew upstream?

Ok, rereading this again at a slower pace. To summarize:

Battery # 2 was replaced
stereo noise will engine running on #1 battery but no noise with engine off
Ground cable found unconnected. Was this a main ground, battery parallel ground or a component's ground?

[jimidemo]

Ok, rereading this again at a slower pace. To summarize:

Battery # 2 was replaced
stereo noise will engine running on #1 battery but no noise with engine off
Ground cable found unconnected. Was this a main ground, battery parallel ground or a component's ground?

Will continue troubleshooting next couple of days. Haven't even looked at since at the lake. Will update post when I have more info. Thanks for assistance.

[jimidemo]

More info....stereo works on battery 1 or 2 with ignition off. AS soon as I turn the key on it starts acting up, engine is not on. Boat is in garage.
As far as wiring, the wire that was not hooked up during my battery #2 install was the main ground to the engine block by the starter. This battery terminal has a short ground cable that ties in at battery #1 ground.
Just messing around I tried my taps without the key on and the sub beats and speaker squelch/scratch. Again this is with the stereo toggle on.

[jimidemo]

Found out that one ground that I did hooked up that day went to amp. Disconnected and all noise went away. Hooked up amp I had laying around and all is well.