KUS GPS Speedometer

Mikko

Petty Officer 3rd Class
Joined
Aug 11, 2003
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76
I wired a new GPS speedometer (figure) and faced a some kind of interference problem (I guess) while starting my 70 hp Yamaha. There is now a constant voltage (12 v) from ignition switch to speedometer (when turned power on). At this point everything is OK, speedometer gets power, GPS founds satellites in reasonable time. Then, when I turn the ignition on, the speedometer gets frozen, but power is still there. This happened most of the times I turned the ignition on, but few times everything remained good after the ignition (as can be seen in the figure). Maybe I should give power to the speedometer after the ignition with a separate switch? All the advice is appreciated.

 

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JoLin

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If that's what happens consistently I'd just put it on a separate switch. KUS markets chinese knock-offs of stuff from major maufacturers, so if it's generally working the way it's supposed to you're ahead of the game. I installed a KUS rudder angle indicator and gauge on my boat 2 years ago at 1/3 the price of VDO. It's still working.

My .02
 

GA_Boater

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Hoping this isn't an indication that your battery is getting old and not holding a charge. But whats probably happening is when starting the engine, the battery voltage drops from the load and it fouls up the speedo. Fish finders often have the same problem when connected to the starting battery.

Adding a switch to power the speedo after the motor is started should allow the speedo to function. Since the speedo work sometimes, use a momentary switch to interrupt power on the speedo 12 volt wire. Then the switch works like a reset switch for those times the speedo freezes. Just hold the switch for a few seconds and when it's released the speedo should power up and function.
 

Mikko

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Aug 11, 2003
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My battery is old, but strong enough to start the motor. In this case, what is the difference between installing a traditional switch (on-off) and a momentary switch? I see that I don't have enough hands to simultaneously turn the key, click the choke and push the momentary switch for the speedo at the start.:)
 

bassman284

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My battery is old, but strong enough to start the motor. In this case, what is the difference between installing a traditional switch (on-off) and a momentary switch? I see that I don't have enough hands to simultaneously turn the key, click the choke and push the momentary switch for the speedo at the start.:)
My battery spins the motor easily but also sets off the low battery alarm on my Helix 5 which means the voltage dropped below 11 volts. All I have to do is hit the clear button but maybe yours is more sensitive to low voltage.
 

GA_Boater

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Push or toggle the switch after starting the motor. How fast are you going at that point anyway?

The reason for the switch is just to break the power to the speedo or the same as rebooting your computer. Whether the switch is a hard on/off or momentary really makes no difference, The purpose is to interrupt power to the speedo and the momentary is a more like a horn button, which would be my preference.
 

Mikko

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If the speedo freezes while motor is running, then a momentary switch would be better, but at the start, to prevent power from going into the speedo, I think the hard on/off would be better.
 

JoLin

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Mikko, GA_Boater had a good thought there. Either type of switch will do the trick equally well, but with the momentary switch you don't need to remember to power it off when you shut down the engine.
 

Mikko

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When I take power from the ignition switch, the speedo will be turned off anyway at the shutdown of the engine regardless of the type and position of the additional power switch to the speedo. Easiest way to test the original problem is to take power to the speedo from the light switch (seen in the figure above). However, I need an additional switch anyway since I don't want to keep always the lights on.
 

Mikko

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Aug 11, 2003
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No Title

48 knots so far with Argo 16 and Yamaha 70 CE
 

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