fuel sending unit for mulitable gauges

[casper5280]

I would like to add a fuel gauge to the my flybridge as there is not one there at the moment. Can I just wire it off the main gauge or the sending unit at the tank. The main gauge will be off because the key will be off when driving from the flybridge. The flybridge key will then turn the fly gauges on up there. Any help would be great

 

[sasto]

Re: fuel sending unit for mulitable gauges

I installed a single pole double throw switch near the origional gauge and ran a wire to the bridge.... switch thrown up reads the bridge gauge....down the lower gauge. I would think your assesment of the key off at one station would make sence.

 

[Silvertip]

Re: fuel sending unit for mulitable gauges

There is internal resistance in any gauge. If you wire two of them in parallel neither gauge will read correctly regardless whether keys are on or off.

 

[sasto]

Re: fuel sending unit for mulitable gauges

There is internal resistance in any gauge. If you wire two of them in parallel neither gauge will read correctly regardless whether keys are on or off.

I couldn't get it thru my head why I installed the switch......now I remember...Thanks

 

[casper5280]

Re: fuel sending unit for mulitable gauges

Thank you for the help. So how exactly could I make a fuel gauge work in the flybridge. I would really like a full gauge pack in the flybridge, and the only thing thats missing is a fuel gauge. If it is a simple thing like a switch I could live with that if that is the only way to do it. I just want it done in a safe and proper way so it works the right way.

 

[Silvertip]

Re: fuel sending unit for mulitable gauges

A single, on-off style switch cannot be used to switch all functions from the cabin to the flybridge. Every "sender" line that runs between the two helms must be switched. So if you have a fuel gauge, tach, temp, oil pressure, etc you need to switch all of those signals. The ground, 12 volt and light can be direct wired and no switching is necessary. You could do this using relays (multiple contacts). Since you will ultimately be at the flybridge at some point and forget to switch over, it is very convenient to have a switch at each helm so (just like a three way switch in your house) so you can switch back and forth from either position. I am not able to draw this out for you at this time but if you do an on-line search using searchg terms like "Dual helm instrument switching" or something similar you might find a diagram. Remember, the start/stop circuit must also be capable of operation from either helm.

 

[Lyle29464]

Re: fuel sending unit for mulitable gauges

my bluewater has 2 senders

 

[wire2]

Re: fuel sending unit for mulitable gauges

There is internal resistance in any gauge. If you wire two of them in parallel neither gauge will read correctly regardless whether keys are on or off.

True, but if one key is off, they're not in parallel. The + from the key is not present, so there's no current through the meter, so no voltage drop. The only live connection is the sender terminal. The active gauge won't "see" it.

A 3-way house lighting circuit isn't practical, that uses 2 switches to control 1 light.

 

[sasto]

Re: fuel sending unit for mulitable gauges

Single pole double throw switch. Your send wire goes to the middle of the switch. The lower fuel gauge wire goes to the top....the upper gauge wire goes to the bottom. Flipping the switch up sends the signal to the bridge. Flipping the switch down sends the signal to the lower gauge. Mine is mounted at the lower helm.

 

[wire2]

Re: fuel sending unit for mulitable gauges

I'm confident that the key being off will isolate the unused gauge, but if you want to go 1 step farther, a pair of miniature 12vdc relays from an electronics supply will do it without additional operator steps. Wire each coil with + from the respective key, ground the other coil lead. Take the sender lead to one side of the n.o. contacts on both, the other contact goes to the respective gauge. Then, no switches to remember.