Dual fuel tanks with single fuel gauge

[stealthdrummer]

I am in the process of rewiring my boat. It has dual tanks that both have sending units. I only have one fuel level gauge. You should know that the fuel pump pulls from both tanks at once. Is there a way to wire both sending units to one gauge without using a switch or should I just use one sending unit? I know I will need to hook up the ground wire on the unused sender and tank but other than that I can't think of a good reason to buy another gauge. Am I on the right track or all wet?

 

[Texasmark]

Re: Dual fuel tanks with single fuel gauge

If you will go to the archives, there are wiring diagrams for fuel level circuits. You can't expect one circuit to monitor two tanks. Probably what will happen is the combined resistance of the floats/resistance value will parallel and just make a mess of your reading......If 50 ohms is required to show 1/4 tank of fuel on the gauge, if you have two tank floats recording 50 ohms, the combined parallel resistance will be half that and the gauge will read half what it should.

You need to separate the circuits so that you can read the level in each tank. Had a 1988 Ford P/U with two tanks, and had the same situation. Have to monitor each tank separately.

Mark

 

[Black as]

Re: Dual fuel tanks with single fuel gauge

Ive done this before and I linked both tanks with a tap, but used the one sender unit, 1 main tank and the 2nd being a reserve tank.

 

[Texasmark]

Re: Dual fuel tanks with single fuel gauge

Ive done this before and I linked both tanks with a tap, but used the one sender unit, 1 main tank and the 2nd being a reserve tank.

Sir, would you care to explain what "a tap" means?

 

[Fl_Richard]

Re: Dual fuel tanks with single fuel gauge

Why not just add a switch to select the tank the gauge is monitoring? Otherwise you run the risk of sucking air from the first empty tank. You'll need to know the lowest tank so you can isolate it anyway.

 

[Black as]

Re: Dual fuel tanks with single fuel gauge

Sir, would you care to explain what "a tap" means?

Sorry, basically it has 2 inlets and 1 outlet and with a manual handle to switch from one to the other. I is the primary tank that has the sender unit, the other is the reserve, so when your nearly empty you switch to the reserve tank that basically fills the primary tank, its simple but does work with little outlay or complicated set ups.

 

[Pez Vela]

Re: Dual fuel tanks with single fuel gauge

Replace your single level fuel gauge with a dual level fuel gauge. Flip a switch to read tank 1 or tank two. You end up with just one fuel gauge which can read both tanks. The switch is connected to the positive leads on both sending units.

 

[Silvertip]

Re: Dual fuel tanks with single fuel gauge

Here is a diagram showing how to wire a switch so you can select either fuel sender and the gauge will read that tank. The diagram shows a temp gauge but it is of no consequence. Fuel gauge works and is wired the same way.

 

[stylesabu]

Re: Dual fuel tanks with single fuel gauge

I used to install dual tanks on pick-up trucks. silvertip switch is what I used. if I was useing a manual valve.They also make electric switches, I installed one on my boat. you'll need a different switch if you only want bto flip 1 switch to switch tanks,.

 

[Just woody]

Re: Dual fuel tanks with single fuel gauge

Here is a diagram showing how to wire a switch so you can select either fuel sender and the gauge will read that tank. The diagram shows a temp gauge but it is of no consequence. Fuel gauge works and is wired the same way.

Years ago I used this same solution for an extra tank on my RV. It worked great and was easy for this English teacher to install.