fuel gauge accuracy

[sam]

I do not rely upon the indicated level as shown on the fuel gauge, but keep a solid record of all fuel used. (averaging 0.7 GPH over time-no generator). However, I would like for the unit to roughly indicate some state of fill other than perpetually full. I have not attempted to sort out this issue yet, but thought I would ask the all knowing list for experience first.

This forum has really become a source of help and sharing.

Sam

LONGHAWK

[Jeff Shukis]

Hi Denis,

 

I did, sort of. I used the already-installed second 5-bolt port on the fuel tank to install a separate NMEA2000 fuel level sender without removing the factory sender. This is only possible if you don't have a Diesel generator since that second port is where the generator gets its fuel.

 

I contemplated installing new water level senders as well since the factory senders are capable of only five readings - empty, 25%, 50%, 75%, 100%. I didn't do so because there is no pre-existing access port on the tanks and I didn't need more accurate readings badly enough to justify drilling.

 

One possibly useful bit of information: The VDO panel on our boats has one additional fuel tank input and two additional water tank inputs. It is therefore possible to install new senders and use the factory panel to read them. 

[Alain Brauckmann]

We had the same problem ... ( Fuel and Water !)

At the beginning Beneteau was not beliving me that this thing is crap. 

When the Benetau official technician was last time on board, we had more than 1/2 full on our gauge. On the Gas-station we filled in a whole tank load. After this he checked every thing and changed the sender from the gauge and send us per mail a new Beneteau gauge that we`ll install in a few weeks ... If this would not fix the problem, I`ll continue to go on the nerves of Beneteau ( not the dealer ... until I have after all my problems a good contact withe Beneteau in France ). 

 

I'll keep you up to date 

 

[foster]

Hello Alain,

 

The local dealer already changed the VDO pannel and it didn't change anything. This is the reason I am changing the system and looking for a reliable one mostly for diesel.

 

Could you give the name ande email of your aftersales contact at Beneteau. How did they fix all your deck problems ?

 

Thank you.

 

Denis

[Alain Brauckmann]

Yes, our VDO was changed, with no results. Thats the reason why they send me a completly new gauge that I'll mount in 2 weeks when I am on board.

The name is coming by PN !

 

[Paul O' Kirwan]

Having the same problem on my 46.  Fuel gauge shows full 100% of the time and my two water tanks show 1/4 full even when topped off.  Now my Battery voltage is suspect as I have installed a brand new engine battery and it is reading 10V. 

Very frustrating and have not found a cure yet and suspect I will have to replace the panel.  I am installing separate battery monitors in any case.

[Bruce Coward]

Must declare interest as we manufacture very accurate fuel, water and very soon Battery monitors that can all show on a single display using a single NMEA2000 backbone. Happy to take any enquiries offline to not mop up forum bandwith. If this email should not have been posted then my humble apologies.

[e-mail]

[Luis Vieira de Sa]

Hello,

 

In my Oceanis 40 I have problems in both the fuel tank and in the water tanks indicators. I am in the process of finding what is causing this. I am sending this message to the dealer as my boat is from 2010. The situation is as follows:

 

1 – Fuel tank – the tank is full and the panel indicates ¾ .When the first gallons are consumed the indicator goes high. Then goes low again

2 – Water tanks – not reliable at all. Sometimes the indicator shows 1/4 , sometimes full and sometimes empty.

 

At first I thought that the problem was the VDO LCD panel because all the readings had problems (except the battery voltages). After some tests with a 1 kOhm potentiometer I think that the panel is OK. Here the tests that I have done.

 

Fuel tank – the sender has the part number 226 -801-015-001C. As far as I know it behaves like a resistor (3 ohm when empty and 180 ohm when full, here in Europe). When I disconnect the 2 wires on the sender I can not get any information on the VDO. When I connect the potentiometer to the 2 wires that go to the VDO, the reading are fine as I change the value of the potentiometer. So I conclude that the VDO panel is OK. As someone stated in this forum the problem is most probable due the boy arm of the sender that gets captive inside the tank. I can not explore this further at this moment as the tank is full. Even if the tank was not full I was afraid to unscrew the 5 screws that hold the sender for inspection – do the nuts (or a round flange) fall inside the tank?

 

Water tanks – In this case I see 3 wires coming from the VDO and they connect to a box. From this box there are another 5 wires. The tank is perforated at 5 heights and the screws connect to those 5 wires. In the VDO LCD panel manual it says that this box “sends a 0V-6V to the gauge”. The 3 wires have the colour red, brown and black. I assume that the signal to the VDO (LCD panel) is transmitted on the brown wire. The black is ground and in the red I was able to measure 12V (the battery voltage) for short periods. It seems that the VDO places 12V on this wire for 1 or 2 seconds and then it switches off this voltage for 10 seconds or so. It looks like it wants to save power. So I connect the 2 extreme terminals of a potentiometer to the red and black wires and the mid terminal of the potentiometer to the brown wire. I connected a voltmeter from the brown to the black wires and tried to read that voltage for several positions of the potentiometer. Note that it is not easy to read this voltage (no scope at the boat) as the voltage appears for a short wile as explained before. In both tanks I got the following readings:

 

0 Volts – no reading (the display does not show the presence of the tank)

0,12V – no reading (the display does not show the presence of the tank)

0,82V – 0 / 4 (empty)

0,90V – 1 / 4

1,60V – 1 / 4

1,65V – 2 / 4

2,10V – 2 / 2

2,14V – 3 / 4

2,65V – 3 / 4

2,80V – 3 / 4

2,90V – 4 / 4

3,30V – 4 / 4

more than X Volts – no reading (the display does not show the presence of the tank)

 

I could not get the value X (I assume about 5V)

 

Water tanks conclusion – to get new “3+5 wire boxes” as from the factory or to install a 3/180 ohm sender?The LCD panel seems OK.

 

Hope this is useful and appreciate any feedback.

 

Regards, Luis

[John Whitehead]

Like Sam and other contributors to this topic, I've found the fuel gauge on my boat worse than useless.  The gauge records full, even when the tank is close to empty.  I've had the unit checked-out several times and the only response I've had is that the tank is shallow and that the depth of fuel in the tank, which is what the gauge is measuring, changes slowly and has to change significantly before the gauge registers the change.  However, this is not a very plausible explanation as the gauge records full when the tank is in fact close to empty.  Like Sam and others, I've found the only practical solution is to calculate the tank's contents from engine hours and average fuel consumption.

 

Has anyone pressed either their dealer or Beneteau direct for a proper solution to this problem?  The simple fact is that we've all been sold a fuel gauge that doesn't work and is unfit for purpose.  Bye the way, does anyone have any evidence that Beneteau follow this forum?

 

John

[foster]

Hello,

 

For the fuel (and water) we have had this problem from the first day. Despite a new version of the vdo soft this persists;

 

i think this is an important safety issue so I monitor hours of engine and generator; BUT THIS IS NOT SATISFACTORY.

So I am changing for an NMEA gauge that will send a compatible signal to the Master Volt Easy displays and the Raymarine E80. There is also an analogic independent display.

By the end of the month I will tell you if this works.

I bought a SCAD sensor for the waste tank but it is not installed yet.

Best regards 

 

Denis

[Paul O' Kirwan]

My VDO panel has now given up completely. It is stuck on Tank 1 water and flashing Battery alarm.  Check with voltmeter indicates house and engine batteries are OK and tanks are full so I have disconnected the panel completely in order to get some peace from the Alarms.  A web search does not reveal a source for a replacement panel so guess I will have to proceed and fit the offshore systems solution.  Benetau less than helpful and not sure if any of you have joined the "Benetau club' online.  They have a real cheek to ask for Euro 70 just to join their club and get access to a customer service contact. 

 

[Paul O' Kirwan]

Just got a Quote from the local Beneteau dealer and they want 400 Euro (Plus shipping) to get a new instrument from France!! Bit steep and I doubt that the new one will be any more reliable than the old one.

[foster]

Hello,

 

In a week I will have installed the new fuel gauge system independent from the VDO panel. It should measure fuel both from an analogic gauge and be displayed on the Raymarine E80 and / or the Mastervolt Easy Displays.

 

Hope this works to get this problem out of the way for good.

 

Denis