Voltage drop at electronics

C

cemiii

New member
My Raymarine plotter/ff shuts down each time I start the outboard. It appears to be extremely sensative to even modest voltage drops. It is currently wired to the main panel.

While it's not the worst to have to reboot it each time, I am wondering aloud if there is a simple fix?

One thought is to wire this one item to the house bank (which shares charging through a combiner). Before I go experimenting, do you think this might work or is there another simple fix?

Chris
 
Correct; putting the electronics is the prefered method. I learned this in the early 70's the hard way. When the engine starts, the battery voltage drops, and also there may be high voltage spikes, which can damage the electronics. The shutdown is protecting the circuits. If you have a volt meter on line, you will find that often voltage drops momentary to 7 volts during start.
 
Chris,

Agreed, the electronics should be on the house battery. But, in the mean time, be sure to get the motors up and running before turning any electronics on. Too many $$$ there to risk damaging them with voltage surges.
 
Dr. Bob and Roger,

So, on a boat that has no house battery (mine) it is always the best procedure to start the motors and have them running BEFORE I fire up any electronics? Makes complete sense.

What is kind of sad is that I know to do that with my Wallas, but I'm not smart enough to figure out on my own that I should be doing that with my GPS/Plotters. :crook

thanks,
 
Even with a dedicated house battery I fire up my engines before turning on any electronics. I want to be sure my house is being charged while underway so I have my starboard bat switch set to 'both' which in my case means starboard start and house. Once engines are fired up and reading a level charge 14+ volts I fire up the electronics. I too read too many stories of bad things happening to electronics with a voltage surge.
 
For those that need electronics running before main engine start up (trolling comes to mind) there are power stabilizers that can be put inline on the electronics power feed that prevents the power drop.

Newmar builds a line of these for 12 and 24 volt applications. Prices range from the mid $100's to just under $500 depending on model.
 
I believe that what Matt is refering to is a "Power conditioner". They filter the incoming voltage, to clean up the spikes, and use a rechargiable battery to supply constant voltage. The one which would be applicable for the c Dory is is the Start Guard, which is a basic alternator filter with a small rechargagble battery: costs about $150. The Nav Pac, has a more sophisticated filter, and the same small battery.

For a lot less, you can build your own, which has a lot more power. Put in a charging diode. There will be 1/2 volt drop, but since the alternator is putting out 14.4 volts most of the time on outboards, that will actually be a better voltage (close to the rated 13.8 voltage)--and then an alternator noise filter and a garden tractor battery. That should cost considerably under $100, and have many times the stand by capacity of the Start Guard.
 
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