Low volts at dash, electrical gremlin somewhere

[ranger098]

This issue has existed ever since I got the boat 2 years ago, and seems to be getting worse. I only have 10-11 volts at my dash, and more when the boat isn't running (12 volts). I just put two brand new optima blue tops in, same result. Using any accessories off the dash (trim tab, blower, heater, or bilge) results in my pp cutting out, and coming back on. Sometimes the voltage is so low that my PP cuts in and out in its own, beeping every couple seconds and there's nothing I can do to stop it. Last year when that was happening, I got up on plane for a minute or two and watched my volt gauge go from 10 to over 12 for no reason. Boat worked great the rest of the day. Radio and ballast pumps DO NOT affect the dash in any way, I can run all 4 pumps together and the PP will be unaffected.

I've poked around with a multimeter and laid under the dash for like an hour, nothing stands out

I don't wanna put her in my dock slip until this is fixed, so any help is appreciated.

[JesseC]

Have you tried bypassing your emergency lanyard? All the power for the dash passes through it on the older models.


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[zabooda]

Check your charging system to see if you have an adequate output.

[ranger098]

That's a good tip, I haven't touched the lanyard. I'll try that soon as I can


Have you tried bypassing your emergency lanyard? All the power for the dash passes through it on the older models.


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[dusty2221]

Possibly time for a new alternator.

[ranger098]

Alternator puts out good voltage, and my battery isolator has good voltage on all connections also. Might try bypassing the isolator to eliminate it as an issue though.

[ranger098]

And now that im thinking more about it, I don't think I have a lanyard......


Have you tried bypassing your emergency lanyard? All the power for the dash passes through it on the older models.


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[BrokeGuy]

Use a voltmeter start testing from the battery forward. Voltage drop is negative post of the battery to any ground wires. Positive post of battery to power anything that's powered. In automotive anything over .25 volts is to much.

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[ranger098]

Ok.. I found that the voltage drop is exclusively on the keyed power accessories. Keyed stuff (and the ignition itself) is only 11.5 volts and the battery is 12.6. So I'm trying to find the power wire that feeds the keyed accessories. I went back to the engine and found that I have 12.5 volts off the starter which is good, but only 11.5 on a purple wire that I believe runs power to the dash. just not really sure where to check after.

So, following broke guys advice, I have 12.5 at the battery, same at the starter, same where the starter wire comes to the main breaker, but I'm losing 1 volt somewhere around the engine harness/main breaker.... At a loss after that

[zabooda]

If you're using a solid state splitter you will have a voltage loss by its design but it is insignificant with good batteries and charging system. Diodes have a 0.7 voltage drop.

[ranger098]

FIXED!!! My electrical gremlin turned out to be a bad battery isolator. it was causing high voltage out the alternator's main battery cable, low voltage out the ignition wire (purple) off the alternator (which feeds the ignition power at the dash), and overcharging one battery and undercharging another. Cleaning all connections at the isolator did not fix the issue, so I replaced it with a perko switch and i now have perfect power everywhere i touch my DMM! And that feels great. Thanks to all that helped.

[zabooda]

Glad you got it fixed and thanks for letting us know. Too many times people on the forum give advice but never get feedback on what the fix was. Also, touching your DMM and it feels good in adjacent sentences may be TMI. LOL.

[ranger098]

Glad you got it fixed and thanks for letting us know. Too many times people on the forum give advice but never get feedback on what the fix was. Also, touching your DMM and it feels good in adjacent sentences may be TMI. LOL.

HAHA good observation. But seriously how often are you reading a post, and there's no resolution? Maddening, especially when someone has the same problem as you!!