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Managing fuel quantity?

Old 12-18-2017, 11:41 AM
  #21  
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Originally Posted by stephenson View Post
pmgia,

That is pretty remarkable fuel tank sending unit ... is it a resistance type? Float or straight?

Thanks!
Its resistance and pretty sure its straight. Whatever the resistance is sending to the fluid level/Evo2 is interrelated. In addition, I tell it how many gallons I've added or more commonly select Full at fuel up, as I understand it, it helps dial in the accuracy.

In modern day electronics there is no reason why we [boat industry] can't have the fuel accuracy as cars or airliners, especially if we are going offshore.
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Old 12-18-2017, 02:10 PM
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Iím not knowledgeable about how the analog a signal is handled by the MFD - I had assumed it was a separate and distinct indication on screen from the fuel level computed by the MFD based on resetting the fuel level (you input your tank size and maybe shape then the MFD takes engine fuel burn data and subtracts it from the Full level following reset).

If someone understands how most MFDs compute and display the two separate inputs it would be nice to hear - all MFDs may not even do this the same way.

Brings to mind - I wonder how modern cars do this? Does the MFD reset and then display fuel level and miles remaining based on an initial input from the fuel sender in the tank? Example: when you fill half way on the car, is this provided to the MFD which then restarts based on engine burn? Does the boat do this too?
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Old 12-22-2017, 09:34 AM
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All,

I asked Garmin about this is a quick chat this morning ... I posed the thought that I wanted to be able to view BOTH the computed fuel remaining (based on the reset minus the burn calculations that the MFD does via the engine interface), AND, the actual fuel in the tank (based on the resistance reading via the analog to digital NMEA interface).

Their answer:

"As long as both of those items are sending the standard Engine Parameters for NMEA 2000 then you can view the "virtual" fuel tank calculated by the device based on the fuel flow rate as well as the actual fuel level and provided by the level sensor.

You will most likely need to add in calibration points for the fuel level sensor for it to function properly."

This is good news - while I haven't proven it, it appears that the Navico cable converts the analog resistance from the tank sending unit, to NMEA digital format for the MFD to read - given some tank settings that I haven't gotten into yet. So, I should be able to "toggle" back and forth between computed fuel remaining based on the reset, and fuel in the tank reading.

I ordered the cables, etc this morning...will report back in when I get finished with the install.
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Old 12-23-2017, 07:50 AM
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Everything is on order ...

Question for anyone...??? Normally, the tank resistance sending is powered via the 12V +/- at the analog gauge ... does the NMEA 2000 backbone provide the power or does the MFD?
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Old 12-23-2017, 09:31 AM
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Originally Posted by stephenson View Post
Everything is on order ...

Question for anyone...??? Normally, the tank resistance sending is powered via the 12V +/- at the analog gauge ... does the NMEA 2000 backbone provide the power or does the MFD?
just semantics, I suppose, as to whether the gauge (or this Fluid Level Sensor) is "powering" the sending unit, or simply measuring it's resistance value.

Regardless, the Navico device connects directly to the sender (and must be "the only device" connected to it)

It has a Load Equivalency Number of 1 - which means it uses 50 mA or less - of power from the NMEA backbone to measure the resistance, convert that to a %, and transmit the PGN.

BTW - the device descriptions state that a Navico (Lowrance, Simrad) MFD is needed to perform calibrations.

Let us know if you are able to perform calibration of it with your Garmin unit.
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Old 12-23-2017, 10:24 AM
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FWP,

That is exactly what I needed to know - I should have looked it up, but don't have a good frame of reference, yet!

The chat I did with Garmin rep was pretty clear it would work - however, I always want to see it!!

Thanks!!!
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Old 12-23-2017, 09:44 PM
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Originally Posted by stephenson View Post
Everything is on order ...

Question for anyone...??? Normally, the tank resistance sending is powered via the 12V +/- at the analog gauge ... does the NMEA 2000 backbone provide the power or does the MFD?
In my case the fluid level sensor is connected only and directly into the NEMA2000 network with a T.
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Old 12-24-2017, 02:57 AM
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My Yamaha gauge is within 2 gallon every fill up. I was happy with That
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Old 12-24-2017, 05:19 AM
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I am pretty sure the Garmin MFD does not need the Data manager module. That is for Navico. The Navico units do not store memory for fuel and Garmin does. It will not hurt anything but a waste of money. I use the fuel remaining on both my boats using motor data. My skiff has no fuel gauge other than a stick they give you. The mfd is very accurate and saves me from pulling the stick out in the middle of a trip. My bay boat has a fluid sensor I need to calibrate. It show half full when fuel remaining is 3/4. The fuel remaining is accurate when filling.
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Old 12-24-2017, 06:36 AM
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r69,

The cable I will be connecting from the two wire tank sender is the Navico/Lowrance fluid level cable - it isnít the device that stores levels, it just provides the sender input to the MFD which then displays it like a gauge would - requires some calibration, but is distinct and separate from the burn rate and fuel remaining computations the MFD provides.
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Old 12-24-2017, 07:33 AM
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Originally Posted by rickboat View Post
Correct, but I've found you have to indicate the change in fuel and then keep the switch on (or use the boat) for some period of time (unknown). If I turn the key on, hit Fill Up All Tanks or Add Fuel to Boat, and then turn the key off, the setting is lost. But if I fill up, start the engine, and then do it and go for a ride, it's fine. Don't know what length of "On Time" is required.

I have exactly the same issue! I figured I was doing something wrong.
Fill up, add the fuel on the GPS, turn the boat off, and it forgets the added fuel.

Fill up, turn the boat off, start her up the next morning, add the fuel amount on the GPS, fish all day, and it remembers.
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Old 12-25-2017, 01:19 PM
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Originally Posted by Cast90 View Post
I have exactly the same issue! I figured I was doing something wrong.
Fill up, add the fuel on the GPS, turn the boat off, and it forgets the added fuel.

Fill up, turn the boat off, start her up the next morning, add the fuel amount on the GPS, fish all day, and it remembers.
Mine stays with a Suzuki engine and Simrad NSS12evo2 MFD, Simrad fluid level sensor, what equipment do you have?
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Old 12-25-2017, 01:25 PM
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Scrbd
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Old 12-26-2017, 05:40 AM
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Originally Posted by pmgia View Post
Mine stays with a Suzuki engine and Simrad NSS12evo2 MFD, Simrad fluid level sensor, what equipment do you have?
The Suzuki engine has a built in Memory module for fuel data so you are not a great example to go by for their issue.
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Old 12-26-2017, 05:27 PM
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Originally Posted by Cast90 View Post
I have exactly the same issue! I figured I was doing something wrong.
Fill up, add the fuel on the GPS, turn the boat off, and it forgets the added fuel.

Fill up, turn the boat off, start her up the next morning, add the fuel amount on the GPS, fish all day, and it remembers.
I had the same problem with a go9 and Yamaha.

I learned I had to have the key 2 clicks over in the "run" position when adding refueling gallons.
If I just have one click over in the "acc position it will not record and save refueling data.

Hope that makes sense
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Old 12-26-2017, 06:48 PM
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Originally Posted by smac999 View Post
get a tank sensor and always know the exact amount. I wouldn't trust a calculation on how much you've used and how much is left.
And I don't trust fuel gauges, notoriously inaccurate, and senders fail and leak. Fuel flow gauged via your ECM is very accurate--the only downside to this kind of system is that you generally need to input any fuel added OR reset your trip fuel. If this is too hard for you, stick to a gauge and never be sure of what you have in there. I used an EP-85 and LMS-200 Lowrance for a while on a boat with no gauge, they were not particularly accurate . But it always estimated flow on the high side, so you always had more in the tank than you thought. my current trailer boat uses tote tanks with a full set of Yamaha Command Link gauges--when that trip useage hits 25 litres, you have 1 litre left. Extremely accurate.
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Old 01-09-2018, 09:11 AM
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Weather has finally warmed a bit - so can continue install of electronics - did one test run with the boat with only the 840xs chartplotter hooked up.so.

I bought a BlueSea 5026 12 circuit with ground fuse block - so it goes in first.

Was looking at the wiring for the fuel level - coming from the tank are four wires - are they as shown in parens? pink (fuel sending), black (ground), blue (gauge lighting). and purple (ignition)?

If this is correct, it looks like I connect up the pink (incoming from fuel sender) to the red on the N2K Navico cable and the black to black. I plan to keep the KW wiring so will tape over the unused connectors (ignition and lighting) and tuck the wiring out of the way somewhere - since I have the white Yamaha gauges (came with the install), I might decide to go to disconnect the fuel tank from the N2K backbone, and put gauge in somewhere later on.
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