Fuel Gauge Calibration

I'm planning to use my Cerbo, not yet installed, the same way. Only for black water and a second 475l water tank, not for fuel. I will not do this kind of calibration, because in my case both these tanks have straight sides and flat bottoms, but for fuel in an irregular tank I can see that it's worthwhile.

Note that Cerbo also takes inexpensive temperature sensors. I wish I had known that before I spent £££ on the Maretron temperature box years ago.
 
Minerva said:
Eh? I think you’ve completely misunderstood the OP’s post.

The column with three decimals is sensor reading therefore it’ll be ohms. The variable resistance is calibrated to give a reading showing how full the tank is and it looks like it shows 0-100% on the chart plotter. seems quite a good idea to me.
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Yes, I'm sure you're correct, but surely the fact that I stupidly took the three decimal points figure incorrectly, didn't warrant all the personal abuse from the op. But hey ho.
 
Posting a useful thread about calibrating sensors didn’t warrant pointless snarky posts from people uninterested in the topic.

We are where we are though. Perhaps next time just keep your thoughts to yourself rather than post unhelpful snark. Or post again, and we’ll be right back here with your hurt feelings.
 
We used NormanS sight tube and marked it off at every 20l, 200l tank. I don't see the need for greater accuracy - unless fuel consumption levels have some auto correct for motoring against the tide etc.

Our water tanks ,used the dip stick method, again no need for greater accuracy.

We never ran out of water nor diesel - in 25 years. But then it was a 'sail' boat and we had a desalinator.
 
Neeves said:
We used NormanS sight tube and marked it off at every 20l, 200l tank. I don't see the need for greater accuracy - unless fuel consumption levels have some auto correct for motoring against the tide etc.

Our water tanks ,used the dip stick method, again no need for greater accuracy.

We never ran out of water nor diesel - in 25 years. But then it was a 'sail' boat and we had a desalinator.
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Like the OP, we like to know how much fuel and water we have and we like to be able to see that, accurately, by looking at a gauge, we're not interested in sight glasses and sticks.

Post#1 is about how the OP calibrated the Victron Cerbo to an odd shaped fuel tank, i don't see that your post adds any value to the thread,
 
Did you keep your old gauge working as well or now only have fuel on the plotter/Cerbo? I'm debating a Cerbo along with a few other Victron goodies, but fancy the idea of keeping the old gauge working as a backup so was going to include one of the KUS dual station converters.
 
The old wires sit next to the sender so I can swap back in seconds but yes it’s Cerbo only. The old gauge was a pain anyway as not in a useful place and had to hold a switch to turn it on.
With the Cerbo I have fuel qty and level at both plotters, all instruments and our phones as well as my watch. It’s also logged to VRM so I can see it when away from the boat. Even if the Internet is off it logs the last level.
I did look into having both and it’s not possible but ultimately this is the more useful setup so I ditched the old gauge.
 
lustyd said:
The old wires sit next to the sender so I can swap back in seconds but yes it’s Cerbo only. The old gauge was a pain anyway as not in a useful place and had to hold a switch to turn it on.
With the Cerbo I have fuel qty and level at both plotters, all instruments and our phones as well as my watch. It’s also logged to VRM so I can see it when away from the boat. Even if the Internet is off it logs the last level.
I did look into having both and it’s not possible but ultimately this is the more useful setup so I ditched the old gauge.
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Super, thanks! Similarly I can't imagine using the gauge if I swapped to a Cerbo with multiple displays, but just like the idea of some redundancy and not having a dead gauge or empty hole in the dash. I suppose I could put something else in it's place...

I'd assumed I could use one of these to have both gauge and Cerbo working simultaneously: KUS Dual Station Convertor JMC00003 for Gauges & Senders
 
paulbrown22 said:
Super, thanks! Similarly I can't imagine using the gauge if I swapped to a Cerbo with multiple displays, but just like the idea of some redundancy and not having a dead gauge or empty hole in the dash. I suppose I could put something else in it's place...

I'd assumed I could use one of these to have both gauge and Cerbo working simultaneously: KUS Dual Station Convertor JMC00003 for Gauges & Senders
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You could buy one of these to replace your existing fuel tank gauge (should fit the existing hole)

https://www.svb24.com/en/kus-fuel-tank-gauge-nmea2000.html

Then just connect it to the N2K network. Will give you an accurate fuel tank reading.
 
I’ve no idea, but it does say can’t mix analogue and digital. Paul will probably comment on these.
I didn’t remove mine, it’s still there for emergency use or a future owner. The sender just connects with two crimp connectors so really easy to swap.
 
jakew009 said:
You could buy one of these to replace your existing fuel tank gauge (should fit the existing hole)

https://www.svb24.com/en/kus-fuel-tank-gauge-nmea2000.html

Then just connect it to the N2K network. Will give you an accurate fuel tank reading.
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Thanks Jake, that's a neat option to fill the hole and retain a traditional gauge, but maybe not quite as redundant if the Cerbo goes down. I was hoping to retain "analogue" gauges as a backup, highly unlikely though they are to be needed, but the thought appealed! Your approach would certainly make things neater and mean I could strip out some wires, which is also appealing...
 
It is also possible with a double pole double throw switch to make the sender switchable if it’s somewhere inaccessible.
 
lustyd said:
That’s pretty cheap. How do you configure the NMEA source on these?
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Shouldn't be any need to do anything with the gauges, they are just displays, But not used any yet.

I have KUS analogue fuel gauges and the senders are also connected to the Actisense EMU1. Are you sure you can't have an analogue gauge in parallel with the Cerbo ? The resistance will be different (as it is with twin gauges) but you should be able to calibrate for that ?
 
PaulRainbow said:
Shouldn't be any need to do anything with the gauges, they are just displays, But not used any yet.
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There would often be multiple nmea sources though so I assume there’s a way to choose which to connect to. I’m feeling too lazy to look though 🤣
PaulRainbow said:
I have KUS analogue fuel gauges and the senders are also connected to the Actisense EMU1. Are you sure you can't have an analogue gauge in parallel with the Cerbo ? The resistance will be different (as it is with twin gauges) but you should be able to calibrate for that ?
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Everyone said no, and the link above did too but I figured you’d know more. Ours is behind the helm by our feet and needs a button push to operate so not worth it. We’d probably need to disable the button to make it work reliably too.
If we had a proper helm like a motorboat I’d certainly make it work one way or another.
 
lustyd said:
There would often be multiple nmea sources though so I assume there’s a way to choose which to connect to. I’m feeling too lazy to look though 🤣

Everyone said no, and the link above did too but I figured you’d know more. Ours is behind the helm by our feet and needs a button push to operate so not worth it. We’d probably need to disable the button to make it work reliably too.
If we had a proper helm like a motorboat I’d certainly make it work one way or another.
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I assumed it would be a "no", the same as running 2 gauges off a single station sender unit as the resistance is no longer as expected...? But if Paul R's works, he's the expert! I can see you could recalibrate the Cerbo to read a modified resistance, but not sure how the original analogue gauge would read correctly.
 
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