Stereo drawing from both house and starter battery banks?

[skunther]

I’ve noticed my starter has been depleting more rapidly than it should, and when viewing the amperage draw on the battery monitor, I noticed that the stereo will draw, depending on the situation, up to 0.4 A from each battery at the same time. I have switched the breaker on and off on both banks and observed the difference. There is also a 12 V charging port that is connected to the stereo breaker, so this will account for some of it. My question though is how the stereo could be wired to both banks at the same time? Am I reading this right? I want to stop the draw from the starter battery, but disconnecting the battery ground turns off the monitor. How can I properly analyze/approach this?

 

[jssailem]

Trace the wires. Often radios are wired to the positive side of a battery

• so that the radio memory is always powered.
• So that you can listen to the radio while all else is shut off

I would start at the radio and follow the leads (positive and negative) till I found them on the source of power. Then differentiate the battery source (house or starter battery) and select the one you desire. You can eliminate the always powered and put the positive connection on the switched breaker. No station memory unless your unit has a battery backup.

 

[Ralph Johnstone]

Basically, the same as what @jssailem said. If you start at the radio and trace back towards your breaker panel, you will find two wires in parallel (one from the house batt. and one from starter batt.) feeding through one wire back to your radio. Hopefully both are past their own breaker.

 

[colemj]

Do you have a 1-2-Both switch on the batteries? If so, is it on 2?

Mark

 

[skunther]

Final update here - situation resolved.

Apparently the red “power” wire coming from the Clarion CMD5 stereo is only for a switch to turn the stereo on and off, not to power it once on. It draws power from the yellow “memory” wire, which was wired to the bilge pump breaker (which seems to be the only breaker in the DC panel wired to the starter battery (should the bilge pump be wired to the house bank instead?)).

I rewired the yellow wire to a DC panel + bus so it always has power and will “remember” its settings, and now the stereo draws power from the house instead of the starter bank.

It seems deliberately wired this to the starter, which seems a bad idea. Why would they do that?

 

[dLj]

Why would they do that?

A question that seems to come up often in cases where some previous work has been exposed where no rhyme or reason seems obvious.... When you find the answer, let us all know....

An example from my boat, I discovered a line fuse buried behind my entire wiring harness that could only be accessed by dismantling the wiring harness. Needless to say that is no longer the case....

dj