New stereo, voltage drops when on, upgrade battery?

cooter272

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Joined
Nov 7, 2016
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3
Hey all.

I have a small ski boat with a single "starting" battery. I recently added a very basic stereo with 4 speakers, no amps or subwoofers or anything crazy. With the engine on and cruising around, as soon as I turn the stereo on the battery volts drop on my gauge and it almost feels like the engine occasionally misses. It stops and volts go back up as soon as I shut the stereo off.

I figured running the stereo with engine off may strain the battery but figured it wouldnt be an issue with engine running. Could I possibly still need to upgrade the battery to something other than a "starting" battery...perhaps a "dual purpose" battery? I dont plan to run the stereo for long periods of time when engine is off; just simply want some music while cruising.

Also, in case it matters, I ran both the red wire and the yellow wire from the stereo to the load side of the ignition switch so it only gets power when key is turned. I also ran the ground wire from the stereo to one of the grounds on the back of the gauges. Could any of this be the cause?

Thanks!
 

alldodge

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Mar 8, 2009
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I also ran the ground wire from the stereo to one of the grounds on the back of the gauges.

Don't know the radio so not sure about the yellow. Start by checking the grounds, but would suggest running a new 12 gauge ground wire from the bat up to the back and attach to a buss bar
 

GA_Boater

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May 24, 2011
Messages
49,038
The yellow wire is the memory keep alive so settings aren't lost when all power is turned off to the radio. On mine all I lose when the battery is disconnected is the clock - The station settings, etc, are unchanged.


The problem may be the ignition switch can't handle the load of the stereo in addition to the rest of the instruments. I would run a dedicated fused power wire and ground wire from the battery. Just make sure you turn the stereo off or it may drain the battery.
 

NYBo

Admiral
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Oct 23, 2008
Messages
7,107
The problem may be the ignition switch can't handle the load of the stereo in addition to the rest of the instruments. I would run a dedicated fused power wire and ground wire from the battery. Just make sure you turn the stereo off or it may drain the battery.
^^This. If you want, you could wire a relay to the ignition switch to switch the 12 gauge lead to the radio.
 

cooter272

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Nov 7, 2016
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3
Thanks for the replies. Today I changed the wires by removing them from the ignition switch and moving them directly to the battery. I also wired in a 15 amp fuse on the red/yellow power wires. So far just running the stereo (engine off) in the driveway, the stereo no longer cuts off and on like it did before, so I have a feeling this probably resolved the issue I was having on the water as well with the engine "missing" and voltage dropping. I'll confirm and report back once I can get it back on the water. Thanks all!
 

isaacs

Petty Officer 2nd Class
Joined
Oct 15, 2013
Messages
153
I suspect the ground for the gauges wasn't heavy enough to handle the additional load of the stereo--especially when it was turned up loud. This may have been causing things to happen via your tachometer which, I think, is connected directly to the coil.
 
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