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I’m building a fuel cell for my car soon. Just gathering material and parts. With the fuel cells I have built in the past, one thing has always bothered me. Not having a way to tell the fuel level without looking inside. Especially when (or if) you have the anti-slosh foam on the inside.

So, anyone here use some sort of level with a gauge that works well in a custom fuel cell? Maybe one that works well with the foam?

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Plans: Single Rotor turbo sub 1000lb machine!

I've used these capacitance senders in my airplane. They work quite well, and you should be able to stick the probe through the foam. No moving parts.
https://www.aircraftspruce.ca/pages/ep/ ... lFuel3.php

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Martin


My build log:
viewtopic.php?f=35&t=14520&start=0
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So by looking at it, I am guessing you mount it at the top of the cell. The long "probe" part will read the level?

This would work with any 5v aftermarket or OEM type of fuel gauge?

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Plans: Single Rotor turbo sub 1000lb machine!

New thing for me!

A quick check shows a much less expensive version on eBay (of course, right?) but the interesting part is that they link to an adapter that uses a voltage to resistance converter for use with "any gauge" Click here: Voltage to resistance converter

It may be of some help

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Chuck.

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Yes, you mount it through the top; if you are making your own fuel cell, you can add a backing plate. The probe will be the depth of your tank, as it measures a change in resistance as the fuel encloses the probe (correct me here, Chuck, if I got this wrong).
You are able to shorten the probe to match your tank, however, I believe there is a limit as to how much. And it works with a regular fuel gauge.
I wouldn't shove the probe through the foam, but core a slightly larger hole so that the probe is properly surrounded by fuel.

_________________
Martin


My build log:
viewtopic.php?f=35&t=14520&start=0
My build video:
https://vimeo.com/143524140 password "matovid"

Awesome. And you may have answered my next question which was can I cut it to length. My fuel cell will not be that deep. As of right now I have it drawn out to 8in in-depth.

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Plans: Single Rotor turbo sub 1000lb machine!

Martin and sen2two, From what I read, the sensor measures the capacitance and converts to a voltage. It should be very linear since the capacitance between 2 conductors, is directly proportional to the dielectric permittivity (dielectric constant) of the material between those conductors. IE, as the fuel level increases, so does the capacitance. There is a circuit that converts that capacitance to a voltage. It also has low and high fuel level adjustments.

It look like the Aircraft Spruce gauges take a voltage signal which this provides. If the "gauge" you wish to use requires a 0-5V voltage signal, then you should be good to go. Most OEM gauges I am familiar with use a variable resistance for the signal. Some use that as part of a internal voltage divider, some use that resistance in a bridge circuit. Those gauges also use sensors with different values of resistance. Worse yet, some have max resistance at low fuel, some have max resistance at full. This makes it impossible to make a blanket statement of what is right without knowing the requirements of the gauge itself.


I mentioned the adapter which is apparently programmable for all of these "resistance" variables and accepting a 0-5V voltage range, just like the Aircraft Spruce sensor.

The AS sensor can be bent and angled so that the entire length can be used without having to cut it to length. Can it be accidentally bent while refuleling? IDK. For ~$80 less than the AS part, that's right only$37 delivered, is the eBay one. It cannot be bent like the AS sensor, but can be cut between 6.6"-10" long. See below.

https://www.ebay.com/itm/Fuel-level-sen ... SwwKtZi3FE

I hope this helps.

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

And don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766

Correct, the sensor sends a voltage, while nearly all gas gauges measure current. Unless you buy the recommended gauge, prepare to do some electrical engineering.

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I wanted something that would not corrode with a standard output value so I could find a matching gauge at a low cost. Come in many lengths but I guess you could modify.

https://www.ebay.com/itm/150mm-Marine-F ... SwVpRbMfTL

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

This type of sensor seems perfect for me, except for it will not work with an OEM fuel level gauge. Which is what I was after.

When looking for gauges, how would I know that a gauge will work with this sensor?

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Plans: Single Rotor turbo sub 1000lb machine!

Sen2two, MV8's proposal will work with some OEM fuel gauges. It says Output Signal: Standard American 240-33 ohms. You need to do research to find out if your OEM gauge uses these sensor values.

What year/model car's gauge are you trying to use?

However, there are at least 2 downsides to MV8's proposal. It uses a float that rides up and down the outside of the tube. If you use foam in your tank, then it may interfere with the float. And it is not adaptable for tank depth.

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

And don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766

Search for "Floatless fuel level sender" on google.

Most will be from VDO.


This place sells them in various lengths.
http://www.tanksinc.com/index.cfm/page/ ... prd346.htm

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My build -> viewtopic.php?t=15585

It will be advertised as "240-33". I just bought a 250mm sensor and gauge. You want the sensor to be as long as possible so it is most accurate near empty. Here are some gauge options. The first gauge below is compatible with multiple sensor input ranges.

https://www.ebay.com/itm/New-Type-Fuel- ... SwDJZb7sBs

https://www.ebay.com/itm/1p-52mm-Digita ... SwWIJb-~Hm

https://www.ebay.com/itm/Universal-240- ... Sw7fBa2FPP

https://www.ebay.com/itm/2-52mm-Univers ... 3049946083

https://www.ebay.com/itm/VDO-Allentare- ... 2319977797

If you want foam,make it a tight fit so the foam doesn't move around and leave an inch gap around the sensor. Even if the foam moves enough to touch the float, it should return when you straighten out. Won't be checking fuel level when hard cornering anyway. My aluminum tank came with filthy foam that I won't use primarily because I don't want to get stranded with a clogged filter because the foam isn't fully compatible with the blend in my area. If making a tank, just weld in some baffles.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Thank you!

Going to look around and purchase a gauge and sensor asap. The fuel cell is designed now. Just need to order the material.

_________________
Plans: Single Rotor turbo sub 1000lb machine!

I just found this thread. I am a manufacturing engineer for the manufacture of these exact type fuel probes for all sorts of mass produced aircraft. I had no idea that the Chinese had lifted our tech and are making cheap versions. To be fair, our products date back to the 1950s using this style of fuel probe, so this isn't exactly new. We just happen to make the majority of them for the larger applications.

There are 2 probes in this type sensor. An inner and an outer probe. The fuel acts as the dialectric in this capacitive probe. More fuel between the two tubes, more capacitance. Cutting this down will definitely mess with how accurate it is, though in our cars, that probably doesn't matter too much. This is likely to be far more reliable and accurate than a float could ever be, especially on a track sloshing around.