Stereo wire to acc switch. Help.

[WildH]

MLA suggestion is not a bad one. Backfiring the 12v to the IGN won't hurt anything but it will power other devices you do not know is running and drain the battery quicker. Having 2 power sources at the same time running from different size fuses/breakers could cause a problem if the radio becomes shorted to ground. The wires designed for 10A radio are now supplied more and wires can melt. Again, being dramatic but things happen and don't want to see anything happen that could be corrected.

Running the yellow radio wire to constant 12v and using the switch to power the red radio wire will work better. I know the switch would have to be on to power the radio and could easily be left on and drain batteries. However, if you turn the batter switch off regularly then this a moot point also.

Yeah I thought about the other coponents possibly being on , but wasn't really worried since they would be on with IGN key anyway which is my alternative. Was thinking the power would be fused for each component but I suppose if I'm sort of back feeding it I may be bypassing any fuses?

Either way my hard work is done and fixing should be easy. Would just need to cut the red power wire at the harness.

[shawnrw]

Has anybody considered making this change at the breaker panel to maintain a constant 12 volt source to the head unit?

I'm getting ready to install a RA-770 HU and the yellow power line requires a 15 amp fuse/breaker. I would like to continue to utilize the 15 amp stereo breaker on the panel as it's currently 15 amps for the stock HU. My hope is an adjustment can be made at the harness or panel level to accomplish this.

Thx

[MLA]

Has anybody considered making this change at the breaker panel to maintain a constant 12 volt source to the head unit?

I'm getting ready to install a RA-770 HU and the yellow power line requires a 15 amp fuse/breaker. I would like to continue to utilize the 15 amp stereo breaker on the panel as it's currently 15 amps for the stock HU. My hope is an adjustment can be made at the harness or panel level to accomplish this.

Thx

What year is your boat? Are you sure the 15S stereo breaker is not already a constant 12V when the main battery switch is on? With that said, if your boat external amps, i would not want to use that helm panel breaker anyway. Easy path to unwanted noise.

[shawnrw]

I have a 2022 Moomba Makai.

I'm pretty sure the 12-volt stereo line is not a constant 12 volts as the radio turns off during starting. The RA70 HU only has one 12-volt line, whereas the newer/older models (RA770) have a yellow and red line, one for constant 12-volt and the other to act as a turnon signal. I agree with the noise concern, but I wanted to keep it as close to stock as possible, given I don't have noise issues now.

[MLA]

That 12V source to the breaker is probably seeing a voltage dip due to the engine load. Cranking the engine has nothing to do with it being a constant 12V on the boat side of the main switch. Again, have you tested it for voltage?

Nowhere am I advocating to change any (yet, lol), simply asking if you measured for voltage. Those breaker panels are supplied once the main battery switch is turned on, There is no key, rocker or toggle that supplies them. Their input terminal is often times, tied to a BUSS bar, so all the breakers have 12V at the same time.

[shawnrw]

I believe I mispoke a little, by starting I meant when moving the key switch from run/off/acc. It appears the rocker switches are hot regardless of the key position, while the radio is hot only in acc or run and the wake computer only works in run. I'm not sure if this power separation is controlled via the breaker panel or at the harness level.

It's prob. best to just wire the radio direct to the panel, but I would like to figure out the power system for the key in the run position. I'm installing thrusters and would like the controller to only power on when the key is in the run position.

[HFarr]

Update us on that thruster install when it happens!

Sent from my SM-G781V using Tapatalk

[MLA]

Im pretty confident, that the 15A stereo breaker is not wired through the ignition key switch. In reality, wiring the 2-wire RA70 to the key switch, was a poor decision.

Moving forward, your new RA670 is a 3-wire harness. Black ground, yellow 12V B+ and red switched IGN. So, as ive said, the 15A breaker likely has 12V when the battery switch is on, and this is where the 670's yellow would terminate. The red would terminate the to key switch's ACC, if thats how you want it to work.

[shawnrw]

The moomba boats with the RA70 head unit only have 1 power wire with no ignition signal wire as most head units have. It’s wired where the power wire is only hot with the key on ACC or Run, checked with a voltmeter. It's odd, but the breaker is not getting power unless the switch is in the positions mentioned above. Curious on what their engineering reason was for wiring it this way.

[Holdmybeer]

The moomba boats with the RA70 head unit only have 1 power wire with no ignition signal wire as most head units have. It’s wired where the power wire is only hot with the key on ACC or Run, checked with a voltmeter. It's odd, but the breaker is not getting power unless the switch is in the positions mentioned above. Curious on what their engineering reason was for wiring it this way.

This might be true for newer boats but my 2015 was not. The yellow and red were connected via factory harness and landed on switched power from the key.

I have since separated them so yellow is constant power and red works off an aux switch that wasn't being used. This way I can listen to the radio without the key yet all power is removed by the main battery switch. Fusion recommended this so A) it doesn't keep surging the new stereo (I went through 2 if them in a month) and B) you only power the music while floating and nothing else has to be on. The radio also doesn't surge while starting or turning the key from ACC thru Off to RUN. Again MLA is correct the 15a requirement is on the yellow wire and should be from a good source (i.e. radio fuse) but red draws minimal current and is wired to a 5A factory toggle switch.