Accessory wiring question

jbing81

Chief Petty Officer
Joined
May 22, 2010
Messages
421
Hey guys,
I had a VHF and a chartplotter installed a couple days ago and I'm having an issue with both. On my panel I have three accessory switches, the installer ran the plotter to one, the VHF to the second, the other is empty and always in the off position. The issue I'm having is if i have the accessories on before i start the motor they'll shut off once the ignition is turned on to start the motor. Once the motor is on i need to power the accessories back on and everything is fine. I had a look at the electrical and noticed the installer ran both the grounds for the plotter and VHF to the third unused switch which is alway off. Could this be the cause of my issue? I rack store the boat and didn't have the time to get it in the waterto test it with the third switch on, but I'm thinking if I leave the unused accessory on it would stop everything from shutting down every time I restart the motor.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Ayuh,.... Startin' the motor draws all the power from the battery,...

My guess is yer toys are turnin' off because of low voltage,...

Turn 'em On, after ya start the motor,...
 

jbing81

Chief Petty Officer
Joined
May 22, 2010
Messages
421
So what should I do to correct the issue? I do a lot of drifting and turning the electronics on 20 times a day can't be normal, or healthy for the equipment.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Get a bigger battery. You can't reduce the current draw so it's a bigger battery or turn stuff on after engine start. That's just how electrics work. By the way, the only time there should be a ground connection on a switch is if said switch is lighted. And equipment grounds do not utilize that ground. They should run to a ground bus or other "equipment" ground point.
 

madolive3

Petty Officer 2nd Class
Joined
Sep 2, 2011
Messages
120
You could get a small 25 to 35 AH deep cycle and wire your acc. to that. It would have the added benefit of not taxing your starter batt. I am wiring a switch so I can select between batteries.
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
I can't see anyway around your situation unless you go for two batteries. Because when you crank the engine, the huge demand for current drops the supply voltage to something lower then your accessories can work with and they shut off. So unless you add more battery capability or install another battery for your accessories, you have to live with it. The exact same thing happens in your vehicles as well. But the manufactory designed the accessories to simply come back on after the voltage returns to its normal state and all is well...
 
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