TL;DR: Key Takeaways
The Queclink CFS300B is the best fuel level sensor for most fleet vehicles: ±0.5% accuracy, wireless BLE installation with no cable runs, a 7-year battery, and IP69 protection. That combination makes it the pick for retrofits where cutting cable runs is not an option, construction and off-road vehicles that need tilt-compensated readings, and fleets that want to avoid battery-replacement downtime for years at a time. The Queclink UFS301 takes over where the tank cannot be drilled: it mounts externally on existing diesel tanks, holds the same ±0.5% accuracy over RS-485, and carries CE/ATEX certification, so it suits taxis, buses, and passenger fleets where the factory gauge has to keep working. This guide compares both Queclink sensors, supplied by EasyNet Technologies, against six competitor models across capacitive, ultrasonic, and resistive sensing technologies.
- Queclink CFS300B is the best fuel level sensor for most fleets – it combines ±0.5% accuracy with wireless BLE installation, a 7-year battery life, and IP69 protection, removing the need for cable runs or frequent maintenance.
- Queclink UFS301 – best for fleets that need non-invasive, drill-free installation on existing diesel tanks with CE/ATEX certification and ±0.5% accuracy via RS-485.
- Omnicomm LLS 6 AI – wired capacitive sensor with CE marking, ±0.5% accuracy, and measuring lengths up to 3,000 mm for large fuel tanks.
- Ticatag TiSmartLVL – ultrasonic sensor offering five interface options (RS232, RS485, analog, BLE, CAN) and Exd II CT5 explosion-protection classification.
- Epsilon ER2-BLE – wireless capacitive sensor with 20 m BLE range and 7-year battery life, at ±1.0% accuracy.
- Epsilon ESx-H – wired capacitive sensor with four selectable output variants (RS-485, RS-232, analog, frequency), at ±1.0% accuracy.
- ROAD Deutschland RE11 – analog reed-switch float sensor rated to +105°C, compatible with biodiesel, heating oil, and petrol.
- Rochester Sensors TLL155 – UK-manufactured build-to-order capacitive sensor with a dedicated low-level alarm contact.
Comparison Table
| Product | Brand | Sensing Technology | Interface/Output | Power | Accuracy | IP Rating | Rating |
|---|---|---|---|---|---|---|---|
| CFS300B | Queclink | Capacitive | BLE 5.4 | Battery (2×2700 mAh) | ±0.5% | IP69 | ★★★★★ |
| UFS301 | Queclink | Ultrasonic | RS-485 | 9–36 VDC | ±0.5% | IP67 | ★★★★★ |
| LLS 6 AI | Omnicomm | Capacitive | RS-485 (LLS/Modbus) | 7–75 V | ±0.5% | IP69K | ★★★★☆ |
| TiSmartLVL | Ticatag | Ultrasonic | RS232/RS485/Analog/BLE/CAN | 9–36 VDC | ±0.5%* | IP68 | ★★★★☆ |
| ER2-BLE | Epsilon | Capacitive | BLE | Battery (3.6 V Li) | ±1.0% | IP67 | ★★★★☆ |
| ESx-H | Epsilon | Capacitive | RS-485/RS-232/Analog/Freq | 9.5–36 V | ±1.0% | Not confirmed | ★★★☆☆ |
| RE11 Series | ROAD Deutschland | Reed-switch float | Resistance/Voltage/Current | Up to 48 VDC | Not stated | IP67/IP6K9K | ★★★☆☆ |
| TLL155 | Rochester Sensors | Capacitive | Resistive/Voltage/Current | Not stated | Not stated | Not stated | ★★★☆☆ |
How EasyNet Technologies' IoT Engineers Evaluated Products
We assessed each sensor against criteria that matter for fleet fuel monitoring decisions:
- Category fit – only devices designed for vehicle and mobile-equipment fuel-level measurement, including two analog senders included as the legacy-gauge option. OEM dashboard gauge senders, marine float senders, LPG autogas sensors, aviation fuel transmitters, and bulk-storage tank gauging systems are excluded.
- Sensing technology – capacitive, ultrasonic, or resistive/reed, each with distinct installation and performance trade-offs.
- Interface and protocol depth – BLE, RS-485, CAN, RS-232, and analog outputs, evaluated for compatibility with GPS trackers and fleet management systems.
- Accuracy and IP rating – high-quality sensors should be waterproof and vibration-resistant, often rated IP65 or higher; we documented each product’s stated accuracy percentage.
- EU/UK market presence – confirmed manufacturer entity, sales channel, or distributor presence in the European market.
Fuel Level Sensor vs. Fuel Pressure Sensor - and Capacitive vs. Ultrasonic
If you searched for “fuel sensor,” you likely encountered results mixing two entirely different products. This guide covers fuel level sensors – devices that report the remaining fuel inside a vehicle’s tank for fuel consumption monitoring and fuel level monitoring. Fuel pressure sensors, by contrast, are diagnostic tools that measure pressure within the engine’s fuel rail or injection system. Different product, different buyer, different purpose.
Fuel level sensors prevent running out of fuel unexpectedly across various sectors: commercial fleets, diesel generators (where real-time fuel monitoring prevents generator failures due to low fuel), and even unmanned aerial vehicles, where fuel sensors are crucial for safe UAV operations to prevent crashes.
The most trusted fuel level sensors include capacitive fuel sensors, reed switch sensors, and ultrasonic sensors. Here’s how each works:
- Capacitive – a probe inserted into the fuel tank measures changes in electrical capacitance between two electrodes as the fuel column rises or falls. The dielectric properties of the liquid level change the capacitance, and the sensor converts that into a digital signal.
- Ultrasonic – an external transducer mounted beneath the tank uses sound waves to determine fuel level by sending ultrasonic waves toward the fuel surface and measuring the echo signal return time. Sound waves travel through the tank wall and reflect off the liquid surface, requiring no physical contact with the fuel. This ultrasonic fuel sensors technology is increasingly popular for non-invasive installations on modern vehicles.
- Resistive / Reed-switch – a float moves up and down with the fuel level, acting as a variable resistor or closing reed contacts. Float arm sensors are traditional and widely used fuel level indicators that change resistance based on fuel level. Resistive fuel level sensors change resistance with fuel level fluctuations, converting those changes into an electrical signal.
For reference, radar level sensors measure liquid levels using microwave technology, though none appear in this fleet-telematics comparison.
Installation matters: capacitive and resistive sensors typically require a probe inserted through the tank (drilling or an existing sender port). Ultrasonic sensors mount externally on the tank’s underside – no tank penetration needed, preserving the factory gauge.
1. Queclink CFS300B Capacitive Fuel Sensor (BLE) - Best for Fleets Wanting Wireless, Drill-Free Installation
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Why It Stands Out
The CFS300B is a battery-powered, BLE-wireless capacitive fuel probe that pairs with a Queclink GPS tracker, dash camera, or router over Bluetooth to report fuel level without running a cable. Its standout feature: up to 7 years of battery life on a single charge-free install.
Key Strengths
- Dimensions: 98 × 45 × (L) mm; adjustable probe length 10–100 cm; weight 1 kg at L \= 70 cm
- Protection: IP69 waterproof – rated for high-pressure, high-temperature washdowns in harsh environments
- Accuracy: 99.5% (±0.5%); resolution 0.1 mm for accurate fuel level measurement
- Connectivity: BLE 5.4 using iBeacon broadcasting; 10 m standard range, up to 100 m interference-free; average current draw 85 μA
- Battery: 2× 2700 mAh Li-SOCl₂; up to 7 years at default 1-second broadcast interval
- Operating temperature: –40°C to +85°C
- Compatibility: aluminum, plastic, stainless steel, iron tanks; gasoline, diesel, LPG fuel type support
- Built-in tilt sensor for fuel level calibration on uneven roads – compensates for fuel sloshing on rough terrain
Possible Limitations
- Wireless range (10 m typical) is shorter than a wired sensor’s cable run – can matter on very large vehicles or trailers
- No stated CE certification in the sourced datasheet
- BLE pairing depends on a compatible receiving device (Queclink tracker, dash cam, or router) being present
Best For
The CFS300B delivers superior performance for fleets retrofitting sensors without cutting cable runs, construction and off-road vehicles needing tilt-compensated precise readings, and fleet managers wanting to avoid battery-replacement downtime for years at a time.
2. Queclink UFS301 Ultrasonic Fuel Sensor - Best for Non-Invasive Installation on Existing Diesel Tanks
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Why It Stands Out
The Queclink UFS301 is a non-contact ultrasonic probe mounted externally on the tank’s underside. It connects via wired RS-485 to a Queclink GPS tracker (e.g., GV305CEU), and the key advantage: no tank drilling, so the factory fuel gauge stays untouched.
Key Strengths
- Power supply: 9–36 VDC; max power consumption 0.36 W at 12 V
- Accuracy: ±0.5%; resolution 0.1 mm – high accuracy for real time monitoring of fuel level changes
- Certification: CE / RoHS / CNEX ATEX – the only own-brand product with formal certification stated in its source document
- IP rating: IP67
- Output: RS-485 (115,200 baud, 8N1); automatic fuel level report every 10 seconds
- Measurement range: 3–100 cm for diesel in aluminum/stainless steel diesel tanks with wall thickness under 5 mm
- Operating temperature: –30°C to +80°C
- Non-contact installation: mounts under the tank, no modifications to the vehicle’s tank required
Possible Limitations
- Requires a wired run (up to ~9 m combined cable) rather than wireless pairing
- Manufacturer documentation specifies diesel; other fuel types are not confirmed
- Installation requires careful sensor-placement selection (avoiding tank obstacles and sending units) for reliable sensor readings
Best For
The Queclink UFS301 is best for fleets that don’t want to drill or modify an existing diesel fuel tank, operators needing CE/ATEX-certified hardware, and vehicles where preserving the factory fuel gauge matters – taxis, buses, and passenger fleet vehicles where vehicle owners expect original instrumentation to function.
3. Omnicomm LLS 6 AI - Wired Capacitive Fuel Level Sensor
Why It Stands Out
The Omnicomm LLS 6 AI is a wired RS-485 capacitive fuel level sensor with an integrated accelerometer for tilt compensation. Omnicomm OÜ is registered in Estonia, and the product is CE marked.
Key Strengths
- Widest range of measuring-part lengths in this comparison: 700, 1,000, 1,500, 2,000, 2,500, and 3,000 mm – fits larger tank depths that other sensors here cannot cover
- Built-in accelerometer addresses fuel sloshing and uneven-terrain problems in a wired format
- CE marked with a stated 8-year designated service life and 100,000-hour MTBF
- IP69K rating; power supply range 7–75 V; operating temperature –40°C to +80°C
- ±0.5% accuracy with RS-485 output (LLS/Modbus protocol, programmable baud rate)
Possible Limitations
- Manufactured in Vietnam, though the business entity is EU-registered (Estonia)
- No accuracy improvement over the Queclink’s UFS301 (both ±0.5%) despite a substantially larger physical footprint
- Sourced technical data comes from the product’s full passport/manual document rather than a standalone datasheet
4. Ticatag TiSmartLVL - Multi-Interface Ultrasonic Fuel Sensor
Why It Stands Out
The TiSmartLVL from French manufacturer Ticatag is a non-contact ultrasonic sensor with a wireless receiver unit. It offers the broadest interface options of any product in this comparison – RS232, RS485, analog 0–5 V, BLE Bluetooth 5.0, and CAN, all on one unit.
Key Strengths
- Five interface options reduce the risk of a mismatch with an existing telematics unit – providing drivers and fleet managers with greater reliability during integration
- IP68 exceeds the IP67 rating of most wired sensors here
- Explosion-protection classification Exd II CT5 – not stated for any other product in this comparison
- Measuring range 3–250 cm; resolution 0.1 mm; operating temperature –40°C to +85°C
Possible Limitations
- No CE certification confirmed in the sourced material
- Accuracy figure (99.5%) is specifically stated for 0# diesel at 25°C; performance with other fuel types is not confirmed
- Usable range depends on tank geometry and tank shape, same as any ultrasonic fuel sensor
5. Epsilon ER2-BLE - Wireless Battery-Powered Capacitive Fuel Sensor
Why It Stands Out
The ER2-BLE from Ukrainian manufacturer Epsilon is a battery-powered capacitive fuel sensor communicating over BLE – the most direct wireless comparison to the CFS300B in this listicle.
Key Strengths
- Longest stated BLE read range in this comparison: 20 m vs. CFS300B’s 10 m standard range
- Same 7-year battery life claim as CFS300B, giving fleets a genuine alternative at a similar maintenance interval
- Suitable for vehicle fuel tanks and stationary fuel storage; works with non-conductive liquids with a fluid permittivity (ε) range of 1.5–5.0
Possible Limitations
- Accuracy (±1.0%) is half the precision of CFS300B’s ±0.5% – a meaningful gap for fuel consumption tracking and optimizing fuel consumption at scale
- IP67 vs. CFS300B’s IP69 – lower-rated against high-pressure washdowns
- Response time to fuel level changes is 35 seconds, explicitly stated – worth noting as a lag for real-time alerting and fuel theft detection
- No CE certification confirmed in sourced material
6. Epsilon ESx-H - Wired Digital Capacitive Fuel Sensor
Why It Stands Out
The ESx-H is a wired capacitive fuel sensor from Epsilon with selectable digital and analog output voltage variants – a configurable, budget-adjacent wired alternative to Omnicomm’s LLS 6 AI.
Key Strengths
- Four interface variants under one product family: RS-485 (ES4-H), RS-232 (ES2-H), analog 0–10 V (ESA-H), and frequency output 500–1,500 Hz – flexible for mixed-fleet telematics setups
- Customizable probe length across a 15–300 cm range
- Power supply: 9.5–36 V; current consumption 25 mA; operating temperature –40°C to +75°C
Possible Limitations
- Same ±1.0% accuracy limitation as its sibling ER2-BLE – half the precision of Omnicomm’s or Queclink’s’ ±0.5% sensors
- No IP rating confirmed in the sourced material
- No CE certification confirmed
- Requires specifying the correct variant and length at order time
7. ROAD Deutschland RE11 Series - Reed-Switch Analog Fuel Level Sensor
Why It Stands Out
The RE11 Series from German manufacturer ROAD Deutschland is a reed-switch float sensor with selectable resistance, voltage, or current output – the analog/legacy-compatible option for fleets whose gauges or PLCs expect a traditional sender signal rather than a digital bus.
Key Strengths
- Widest operating-temperature ceiling in this comparison: –40°C to +105°C, suitable for industrial equipment near engine heat
- Broadest stated media compatibility: diesel fuels (including biodiesel), heating oil, petrol, alcohol, oils, water, and silage additives
- TÜV PED+2000, IATF 16949, ISO 9001:2015, and ISO 14001 certified manufacturing
- Explicitly lists trucks, buses, construction machinery, and agricultural/forestry equipment as application areas
- Reed-switch sensors have fewer wear points than potentiometer types, leading to better durability. Reed switch sensors are also popular for marine and generator applications due to their vibration resistance.
Possible Limitations
- Analog output only (resistance/voltage/current) – no native digital bus output confirmed, unlike every other product here
- Float-resistive sensors are inexpensive and reliable but can suffer from mechanical wear due to moving parts, unlike solid-state capacitive and ultrasonic alternatives
- No CE certification confirmed (TÜV/IATF/ISO certifications are confirmed instead)
- Resolution is 7–9 mm (high-res variant) or 14–20 mm (standard), though high-resolution readings can be achieved with more reed switches or digital sensing
8. Rochester Sensors TLL155 - Configurable Capacitance Fuel Level Sensor
Why It Stands Out
The TLL155 from Rochester Sensors UK Limited, the UK arm of US-based Rochester Sensors, is a capacitance level sensor sold as a build-to-order configuratio – output type, liquid, and length are all specified at order time. It is the most customizable but least fully-specified product in this comparison. Voltage, accuracy, IP rating, and certification are not stated in the sourced specification document and are omitted here rather than estimated.
Key Strengths
- Only sensor in this comparison with a built-in low-level alarm contact specified independently of the main output signal (standard alarm at 12.5% of active range, closes on fall)
- Customer-specified probe length between 200 mm and 1,100 mm; 1/2″ BSPT thread; 4-pin Superseal 1.5 connector
Possible Limitations
- Voltage, accuracy, IP rating, and certification are genuinely not stated – this is a build-to-order form, not a fixed-performance datasheet
- Requires the buyer to specify output type and liquid at order time rather than selecting a fixed off-the-shelf configuration
- No digital (RS-485/CAN/BLE) output variant confirmed – only resistive, voltage, or current outputs, similar to flow meters or legacy gauge inputs
How to Choose the Right Fuel Level Sensor
The best fuel level sensor type depends on specific applications and conditions. Accurate fuel measurement reduces emissions and optimizes consumption across your fleet. Here’s a structured framework:
Choose Based on Tank Access
- Non-invasive external mount: UFS301 and Ticatag TiSmartLVL mount under the tank – no drilling. Ideal for preserving factory gauges.
- Probe-in-tank: CFS300B, Omnicomm LLS 6 AI, both Epsilon models, ROAD RE11, and Rochester TLL155 all require insertion through the tank top or side. Tank depth and shape should be considered when selecting a fuel level sensor. Tank dimensions are crucial for selecting capacitive sensors, and multiple sensors may be needed for vehicles with complex tanks.
Choose Based on Power Model
- Battery/wireless (CFS300B, Epsilon ER2-BLE) avoids cable runs but introduces a long-dated battery-life ceiling.
- Wired (all others) requires cable installation but has no battery to plan around – the power supply is continuous from the vehicle.
Choose Based on Interface Compatibility
- RS-485 is the most common digital interface across this list (UFS301, Omnicomm, Epsilon ESx-H).
- BLE (CFS300B, Epsilon ER2-BLE) and CAN (Ticatag) need a receiving device that supports them.
- Analog/resistive (ROAD RE11, Rochester TLL155) connects to a gauge or PLC input, not a telematics protocol.
Choose Based on Accuracy Requirements
- ±0.5% sensors: UFS301, Omnicomm LLS 6 AI, CFS300B, Ticatag. This level of high accuracy supports precise fuel management and helps prevent fuel theft through real time data on drains and refueling.
- ±1.0% sensors: both Epsilon models. Sensors that offer user-calibration can ensure 1-2% accuracy.
- Unstated: Rochester Sensors TLL155.
- Certification is a genuine differentiator: only UFS301 (CE/RoHS/CNEX ATEX) and Omnicomm (CE) are the only two products whose source documents carry a product conformity mark – ROAD Deutschland’s catalogue shows manufacturing-system certifications (TÜV/IATF/ISO) instead. Factors like fuel compatibility and environmental conditions are critical when choosing a fuel sensor. Ensure sensor materials are compatible with the fuel type. Choosing sensors with no moving parts increases durability in harsh environments. Unlike pressure-based level methods that rely on hydrostatic pressure, the ultrasonic models in this list determine level without direct fuel contact.
Integrating a Fuel Sensor with Your Fleet's GPS Tracker
A level sensor on its own produces data. Turning that data into actionable fuel level monitoring – detecting drains, verifying refueling volumes, providing accurate measurements for fleet reporting – requires pairing the sensor with a GPS tracker or telematics unit. Matching sensor output with display specifications is crucial for accurate readings. Three pairing models appear across this comparison:
- BLE pairing – CFS300B and Epsilon ER2-BLE broadcast wirelessly to a compatible tracker, dash cam, or router. The tracker must support BLE input.
- Wired RS-485/CAN connection – UFS301, Omnicomm LLS 6 AI, Ticatag TiSmartLVL, and Epsilon ESx-H connect directly to the tracker’s input terminals. RS-485 is the most broadly compatible digital option across GPS tracker brands.
- Analog/resistive connection – ROAD Deutschland RE11 and Rochester Sensors TLL155 feed a gauge or PLC, not a telematics unit. Integrating these into real time monitoring requires an intermediary converter or a tracker with analog input support.
A fuel sensor reports real time data on the fuel level; fuel theft prevention is a fleet-management and procedural outcome built on that data, not something the sensor does autonomously. Fleet managers still need alert thresholds, geofencing rules, and response procedures to act on what the sensor provides.
Frequently Asked Questions
What's the difference between a capacitive and an ultrasonic fuel sensor?
A capacitive fuel sensor inserts a probe into the fuel tank and measures the electrical capacitance change as the fuel column height shifts – the dielectric properties of the fuel versus air create a measurable difference. An ultrasonic fuel sensor mounts externally and uses sound waves to bounce off the fuel surface, measuring return time to calculate level measurement. The right fuel sensor depends on whether tank drilling is acceptable: if you can’t penetrate the tank, ultrasonic (UFS301, Ticatag) is the path; if probe insertion is fine, capacitive (CFS300B, Omnicomm) typically offers an in depth understanding of level with fewer geometry constraints.
Will these fuel sensors work with any GPS tracker, or only specific brands?
It depends on interface support, not brand exclusivity. CFS300B and UFS301 are designed for pairing with Queclink trackers, but RS-485 output (UFS301, Omnicomm, Epsilon ESx-H) is a standard protocol that most telematics units accept. BLE sensors require the tracker to have Bluetooth input. Analog sensors (ROAD RE11, Rochester TLL155) feed gauges or PLCs, not telematics buses directly. Always confirm your tracker’s input specifications before selecting a sensor.
How accurate are fleet fuel level sensors, and does accuracy vary by sensor type?
Yes, accuracy varies meaningfully. UFS301, Omnicomm LLS 6 AI, and CFS300B all state ±0.5% accuracy. Both Epsilon models state ±1.0%. Rochester Sensors’ TLL155 does not state accuracy at all. Regular checks can prevent inaccurate readings in fuel sensors, and corroded connections can cause inaccurate fuel gauge readings over time.
Can a fuel sensor stop fuel theft on its own?
No. A fuel sensor provides real time data on the fuel level – it detects and reports a drain event, but it cannot physically prevent fuel theft. Fuel theft prevention is a procedural outcome: the sensor feeds data to a fleet management platform, which triggers alerts, logs events, and enables fleet operators to respond. In severe cases, combining a sensor with geofencing and rapid-response protocols is what actually deters theft. The sensor plays a vital role, but it is one component in a broader fuel management system, not an autonomous solution.
Is a wireless (BLE) fuel sensor as reliable as a wired one?
Wireless BLE sensors like the CFS300B and Epsilon ER2-BLE avoid cable runs and simplify installation, but there are trade-offs. BLE range is limited (10–20 m typical), and metal tank walls or interference from other electronics can attenuate the signal. Wired RS-485 sensors have no battery to plan around and offer continuous, uninterrupted data – providing drivers and fleet managers with a connection that doesn’t degrade over time. Fuel sensor replacement in wired setups requires draining the fuel tank first, adding downtime. Neither approach is universally superior – the choice depends on your fleet’s installation constraints and maintenance capacity.
