Tank senders

[Torblimey]

Hey all,

Just a quick query.

 

I currently do not have tank senders or guides on either my fuel tank or water tank, measurement of contents is either visual or by using a graded bamboo stick poked into the fuel filler point.

 

I do have a cerbo gx with spare level connection points placed approximately 12ft from the fuel tank and around 50ft from the water tank.

 

Just wondering what you might have used or suggest using should I want to place a tank sender in each tank and then connect to the cerbo to provide and inclusive data read for the tanks on my NB.

 

Wired, radar, float, cabled or usb considered I would just like to include it with the cerbo gx.

 

Cheers for any thoughts.

 

Tor.

[Tonka]

More to go wrong. 

Just use a dip stick for the diesel

[Torblimey]

10 minutes ago, Torblimey said:

by using a graded bamboo stick poked into the fuel filler point.

@Tonka

 

Yeh already do, it came with the boat 6 years ago, would like something a bit more 2000's than 1800's 😂

[Jen-in-Wellies]

Just now, Torblimey said:

@Tonka

 

Yeh already do, it came with the boat 6 years ago, would like something a bit more 2000's than 1800's 😂

Canal technology is 18th century technology. I have 21st century LiFePO4 batteries, and a home made electronic water tank contents sender and display, but still use a graduated stick to find the fuel level. 

[Tonka]

4 minutes ago, Torblimey said:

@Tonka

 

Yeh already do, it came with the boat 6 years ago, would like something a bit more 2000's than 1800's 😂

You do know the simpler it is the more efficient 

[Torblimey]

6 minutes ago, Jen-in-Wellies said:

Canal technology is 18th century technology. I have 21st century LiFePO4 batteries, and a home made electronic water tank contents sender and display, but still use a graduated stick to find the fuel level. 

 

Trouble is no matter how hard I look I can't find the contact points on the stick to wire it into the cerbo, it also means I have to leave the fuel filler cap off when I'm away to give a constant read on the tank level which I've found my ring doorbell camera/monitor doesn't pick up very well.

 

[Jen-in-Wellies]

1 minute ago, Torblimey said:

 

Trouble is no matter how hard I look I can't find the contact points on the stick to wire it into the cerbo, it also means I have to leave the fuel filler cap off when I'm away to give a constant read on the tank level which I've found my ring doorbell camera/monitor doesn't pick up very well.

 

You need one of them there Bluetooth smart sticks. 😀

[blackrose]

29 minutes ago, Tonka said:

You do know the simpler it is the more efficient 

 

Efficiency may be variable from person to person because it's dependant on how or even if a fuel gauge is used. 

 

For example, if an accurate electronic gauge is on the wall and is easy to read then there's a fair chance the person using that system will have a better idea of how much fuel is in their tank than the person (like me) who uses a dipstick but rarely actually uses it because of the hassle of finding it, dipping it, wiping the diesel off and putting it away. In my case I hate getting diesel on my hands so I'd put on some latex gloves first too. The electronic version sounds much more efficient to me.

 

 

Edited July 13, 2025 by blackrose

[Tonka]

1 minute ago, blackrose said:

 

Efficiency may be variable from person to person because it's dependant on how or if a fuel gauge is used. 

 

For example, if an accurate electronic gauge is on the wall and is easy to read then there's a fair chance the person using that system will have a better idea of how much fuel is in their tank than the person (like me) who uses a dipstick but rarely actually uses it because of the hassle of finding it, dipping it, wiping the diesel off and putting it away. In my case I hate getting diesel on my hands so I'd put on some latex gloves first too. The electronic version sounds much more efficient to me.

 

 

But how do you know the guage is accurate 

[NB Saturn]

1 minute ago, Tonka said:

But how do you know the guage is accurate 

 

Empirical testing over time. If you never run out it must be somewhere near.

[Jen-in-Wellies]

1 hour ago, blackrose said:

the person (like me) who uses a dipstick but rarely actually uses it because of the hassle of finding it, dipping it, wiping the diesel off and putting it away. In my case I hate getting diesel on my hands so I'd put on some latex gloves first too.

I have mentioned this before, but it has been a while, so time for a repeat. My dip stick is calibrated from the top of the tank to the diesel surface, rather than from the bottom of the tank filler neck to the diesel surface. That way, the stick doesn't have to be dipped to the bottom to find the volume of diesel  in the tank. 

 

To use it, I slowly lower the stick in till I see it just touch the surface, then read the volume from the stick. In my case, this is the litres needed to fill up to the top. Subtract from 225l and that gives the volume in the tank. This way means only a tiny drip of diesel is on the tip of the stick. The rest remains dry. In this picture, the tank is nearly full. Perhaps 30l from the the top. 

 

[PeterF]

I have fresh water, black water and diesel gauges from MCS. However, these are voltage based senders and to get them on the Cerbo GX you need the Victron GX Tank 140 accessory. The other thing you might he able to do for fresh water if you can access the top or bottpm of the tank is a Mopeka Bluetooth sender, but these need to be close to the cerbo as Bluetooth does not travel through steel bulkheads, or use a Bluetooth dongle on an extension USB cable.

 

https://www.mcsboatproducts.co.uk/

 

https://mopeka.com/shop-our-products-mopekaiot/

[Kingdom Isambard Brunel]

1 hour ago, Jen-in-Wellies said:

I have mentioned this before, but it has been a while, so time for a repeat. My dip stick is calibrated from the top of the tank to the diesel surface, rather than from the bottom of the tank filler neck to the diesel surface. That way, the stick doesn't have to be dipped to the bottom to find the volume of diesel  in the tank. 

 

To use it, I slowly lower the stick in till I see it just touch the surface, then read the volume from the stick. In my case, this is the litres needed to fill up to the top. Subtract from 225l and that gives the volume in the tank. This way means only a tiny drip of diesel is on the tip of the stick. The rest remains dry. In this picture, the tank is nearly full. Perhaps 30l from the the top. 

 

How do you tell when it is just touching the surface?

[Jen-in-Wellies]

5 minutes ago, Kingdom Isambard Brunel said:

How do you tell when it is just touching the surface?

Try it. When the stick touches the surface a wave is sent out across the diesel surface that is easy to see when looking down the roughly 2" filler pipe on my boat. There is a minimum BSS size for fillers, so yours won't be much smaller. 

[nicknorman]

1 hour ago, Jen-in-Wellies said:

I have mentioned this before, but it has been a while, so time for a repeat. My dip stick is calibrated from the top of the tank to the diesel surface, rather than from the bottom of the tank filler neck to the diesel surface. That way, the stick doesn't have to be dipped to the bottom to find the volume of diesel  in the tank. 

 

To use it, I slowly lower the stick in till I see it just touch the surface, then read the volume from the stick. In my case, this is the litres needed to fill up to the top. Subtract from 225l and that gives the volume in the tank. This way means only a tiny drip of diesel is on the tip of the stick. The rest remains dry. In this picture, the tank is nearly full. Perhaps 30l from the the top. 

 

Never thought of that before, it’s a great idea. Well it would be if you have a tank like yours. Our tank is under the engine with a long flexible and slightly curving filler pipe from gunnel to the tank. Which is why we have an electronic gauge!

[Jen-in-Wellies]

1 minute ago, nicknorman said:

Never thought of that before, it’s a great idea. Well it would be if you have a tank like yours. Our tank is under the engine with a long flexible and slightly curving filler pipe from gunnel to the tank. Which is why we have an electronic gauge!

Yes, it only works if you can see the diesel! However that applies to most narrowboats and widebeams with integral steel stern tanks.

[nicknorman]

We have the MCS fuel gauge, top entry onto the tank. It does rely on not losing any air pressure ever, but of course it does, slightly. I have to pump it up about once a year but it only takes a few minutes.

 

In the OP’s case I have no idea what sort of input the Cerbo needs. The sensor for the MCS device is a pressure sensor which is a bridge, so the output would be very small and some amplification would likely be needed to get it into a range suitable for the Cerbo. Or just steal the principle and find a low pressure sensor with a suitable output, the rest is just plumbing.

 

https://www.mcsboatproducts.co.uk/our-products/fuel

Edit: looks like they’ve changed the design. Ours had a Schroeder air valve to top the pressure up in the down-pointing pipe, and it was much narrower than the type shown.

Edited July 13, 2025 by nicknorman

[Wafi]

1 minute ago, nicknorman said:

Never thought of that before, it’s a great idea. Well it would be if you have a tank like yours. Our tank is under the engine with a long flexible and slightly curving filler pipe from gunnel to the tank. Which is why we have an electronic gauge!

I have the same problem; currently addressed with a long flexible stick, but a gauge would be easier. It also occurs to me that cutting a hole in the top of the tank to fit a gauge would provide an easy way to suck water out of the bottom of the tank. I tried taping a tube to my long flexible stick, but it sucked up clean fuel so I suspect it's not reaching the bottom of the tank.

[Slim]

3 hours ago, Torblimey said:

@Tonka

 

Yeh already do, it came with the boat 6 years ago, would like something a bit more 2000's than 1800's 😂

KISS

[Torblimey]

2 hours ago, PeterF said:

I have fresh water, black water and diesel gauges from MCS. However, these are voltage based senders and to get them on the Cerbo GX you need the Victron GX Tank 140 accessory. The other thing you might he able to do for fresh water if you can access the top or bottpm of the tank is a Mopeka Bluetooth sender, but these need to be close to the cerbo as Bluetooth does not travel through steel bulkheads, or use a Bluetooth dongle on an extension USB cable.

 

https://www.mcsboatproducts.co.uk/

 

https://mopeka.com/shop-our-products-mopekaiot/

Thanks Peter,

 

The cerbo has various sensor points that can be used directly for resistance type senders or as you state adding the victron tank accessory will give me a whole range of options.

I just wondered if anyone had fitted senders and if they had worked, nice to see someone that has.

Although the dipstick works and lifting the water tank lid to see it's contents is all well and good I want a little integration with my modern setup hidden deep within the 24yr old  steel skin 😁

[IanD]

23 minutes ago, Torblimey said:

Thanks Peter,

 

The cerbo has various sensor points that can be used directly for resistance type senders or as you state adding the victron tank accessory will give me a whole range of options.

I just wondered if anyone had fitted senders and if they had worked, nice to see someone that has.

Although the dipstick works and lifting the water tank lid to see it's contents is all well and good I want a little integration with my modern setup hidden deep within the 24yr old  steel skin 😁

I've got level sensors on diesel, black and fresh water tanks (Cerbo + Tank 140), they all work well and I find them useful.

 

If people want to guess or use a dipstick then go ahead, but that's not a good reason to disparage those who think gauges are better... 😉

Edited July 13, 2025 by IanD
Changed you to people

[Torblimey]

1 minute ago, IanD said:

I've got level sensors on diesel, black and fresh water tanks (Cerbo + Tank 140), they all work well and I find them useful.

 

If you want to guess or use a dipstick then go ahead, but that's not a good reason to disparage those who think gauges are better... 😉

Umm,

 

I was actually thanking Peter for his positive input with the sensor links included.

Currently doing things the "old" way is the reason for asking advice on sensors or sender's people might use as I explained.

Disparaging people was the last thing on my mind and is the reason I rarely ask for advice on the forum.

[IanD]

10 minutes ago, Torblimey said:

Umm,

 

I was actually thanking Peter for his positive input with the sensor links included.

Currently doing things the "old" way is the reason for asking advice on sensors or sender's people might use as I explained.

Disparaging people was the last thing on my mind and is the reason I rarely ask for advice on the forum.

That wasn't referring to you (post edited to make this clearer), it was the usual culprits who always think old is good and new is bad, regardless of whether this is actually the case or not... 😉

 

The sensors on mine are 4-20mA 0.1bar ones, which are reliable and accurate but not cheap.

 

BTW I'd also recommend a Ruuvi tag on the calorifier... 😉

 

Edited July 13, 2025 by IanD

[Torblimey]

I must admit I bought a decent cobalt stepped hole borer to help a friend refit a slightly larger battery isolation switch in his steel bulk head a few weeks back.

It goes through steel as though it's made of soft plastic, literally peels the steel away at slow speeds to the hole size you desire.

This in turn spurred my thoughts on finally getting senders fitted into both tanks as there are plenty of available flat surface areas I can bolt/tap into.

The only issue is with regards the water tank sensor being placed 50 odd ft from the cerbo in the bow of the NB.

Bit of a distance to get connected up with regards that one.

 

 

"BTW I'd also recommend a Ruuvi tag on the calorifier... "

 

Now that is an interesting addition and something to consider as I shall replace the old cauliflower at some point soon.

It's currently in the electrical cupboard, upright 80l twin coil gently weaping water from the blown immersion and corroded mixer valve.

No isolation taps, no service points and no drainage tap (yeh that needs sorting).

All on the to do list 😲

Edited July 13, 2025 by Torblimey
Merging created poor clarity.

[PeterF]

If you have a Cerbo then it is useful having info at a touch on the screen.