Overview: EON800 Tether System for Freefly Systems ALTA X
EON800-AX Overview | Freefly Systems ALTA X
Last updated
EON800-AX Overview | Freefly Systems ALTA X
Last updated
XM2's EON800-AX Tether System is a bolt-on, tether power and control solution for the Freefly Systems ALTA X. High-voltage cabling and four fiber optic cores are embedded within the Tether Fiber Cable for powered connectivity. Generator Power is transmitted to the Tether Ground Station (TGS). The TGS then delivers power and fiber connectivity through the Tether Fiber Cable to the ALTA X (via the Air Power Unit) and its payloads. The EON800 has been specifically designed to securely provide the ALTA X with control, connectivity and extended flight time.
Continuous Power Delivery
4500W
Max Flight Height
400ft | 120m
Payload
34lb | 14kg Max Payload
7x Dedicated Payload Fibers
Features
Battery Management System and on-board failsafe
Wired MAVLink Connection
EON800-AX | ALTA X Air Power Unit (APU)
EON800 Tether Ground Station | Portable and User Friendly
The EON800 Air Power Unit (APU) is engineered for easy and rapid installation, seamlessly integrating with the ALTA X. The APU's front ports deliver power and fiber connectivity from the tether cable to the ALTA X. To keep the power components running efficiently, the APU fans pull cool air through the system.
Quick-Release Mounting Pins directly attach to the pre-existing attachment points on the ALTA X Battery Tray.
The APU is designed to mount two 6S 10,000 mAh backup batteries, each plugging into the APU panel-mounted connections. Power Output Pigtails are installed on the APU, connecting to the ALTA X standard Battery Inputs.
The serial port connects the APU with the ALTA X flight controller.
The EON800 Tether Ground Station (TGS) distributes high-voltage power from an energy source, through the tether cable and up into the ALTA X via the APU. The TGS is designed to fit around a 4U enclosure for rack mounting. The system's front panel includes an LCD user interface, allowing operators to monitor the ALTA X tethered performance.
An ethernet port on the front of the TGS provides a UDP MAVLink feed to the ALTA X flight controller.
'ALTA QGroundcontrol' is enabled through the tether cable, similar to conventional usage over USB or Wi-Fi.
To FlyByWire, establish a connection between the TGS, a laptop and a preprogrammed HOTAS for ALTA X.
When flying the ALTA X over the MAVLink network, be very careful with the configuration, as in-proper configuration may result in a crash, or arming the aircraft unintentionally.
For safety purposes, Freefly Systems strongly recommends ensuring that the ALTA X is capable of manual flight mode. This serves as a crucial safety feature in the event of a GPS malfunction, enabling essential manual control of the aircraft.
The power draw of the ALTA X depends on the weight the aircraft is carrying, as well as other factors like wind speed and altitude. In ideal conditions at sea level, the graph below shows the current draw of the ALTA X when powered by the EON800 system. The EON800-AX Air Power Unit provides 46-50V DC power to the Drone and Payload. The output voltage of the Air Unit varies with load. The graph below shows how output voltage varies with current draw.
The maximum capacity payload for the EON800 powering the ALTA X depends on many factors. The graph below shows the maximum possible payload for any given altitude, at various payload power draw levels. These figures are calculated for a drone using 6s 10,000mAh batteries, using XM2 SLG-20 Retractable Landing Gear. These maximum payload weights reflect the limitation on gross weight discussed below.
The backup batteries operate in parallel with the power system. The voltage of the backup batteries will float at the output voltage of the tether system, depending on the load. This means that as load increases (takeoff), the backup batteries will discharge, and as load decreases (landing), the backup batteries will be charged. The voltage of the backup batteries will also fluctuate as the batteries handle burst current to react to wind gusts, etc.
The backup batteries are designed to supply burst current and reserve capacity, acting as a backup in case of a power system failure, like when the generator runs out of fuel. This backup ensures the capability for emergency landings. The appropriate size of this backup battery depends on the aircraft and payload. For example, a suitable size for the 25-30kg ALTA X would be two 6s 10Ah batteries in series.
The EON800 may cause a reduction in voltage output under heavy loads, impacting the backup batteries' ability to maintain full capacity. When choosing the right battery size, consider this aspect for optimal performance.
The Tether Fiber Cable consists of four single-mode fibers. One of these fibers is specifically allocated for controlling the ALTA X, while the remaining three fibers are available for the users payloads.
Typically, two out of the three payload fibers establish a full-duplex connection with the payload device, while the third fiber serves as a backup or secondary link. This third fiber ensures continued functionality in case of any damage to the primary fibers and can also support simplex or half-duplex modes for an extra device. We've designed this versatility to enables multiple payload setups, such as operating an LTE radio and a camera simultaneously, each with its independent fiber connection.
The EON800-AX Air Power Unit has a serial port to connect to the ALTA X flight controller. The Ethernet Port on the Tether Ground Station provides access to this MAVLink feed via UDP.
When flying the ALTA X tethered, understanding the difference between Gross Weight and Maximum Takeoff Weight (MTOW) is essential.
Gross Weight – The total weight of the aircraft, including the attached flying Tether Fiber Cable.
MTOW – The maximum allowable weight for safe aircraft operation, set at 34.8 kg (76.8 lbs) by Freefly Systems.
To ensure safe and efficient performance, keep the aircraft’s Gross Weight at or below the MTOW limit.
For higher-altitude tethered flights, reduce the takeoff weight to as low as 30.4 kg (67 lbs). This adjustment compensates for the additional weight of the tether cable as altitude increases. As the aircraft ascends, more of the tether cable is lifted, contributing to the Gross Weight.
Refer to the performance graphs in this guide for detailed insights on how weight adjustments impact flight performance.
The EON800 can deliver up to 100 Amps of power to the Alta X aircraft. For optimal performance and to prevent system strain, it is recommended to keep the current draw below 90 Amps. If the current exceeds 95 Amps, the system will trigger an LCD warning message and an audible alert to notify the operator.
Aircraft power consumption varies based on several factors, including:
Takeoff weight
Tether weight
Wind drag
Altitude above sea level
Payload power requirements
Keep in mind that while certain payloads may be manageable in calm, low-altitude conditions, the same payload may be impractical at higher altitudes or in stronger winds due to increased power demands.
When the aircraft exceeds the power systems capacity, it safeguards itself by limiting the power. This extra power then comes from the backup batteries, causing them to slowly lose power. The system alerts you, allowing you to either fly lower to use less power or land the drone and lighten the payload. If the aircraft draws more power than the power system can provide, the current will be limited to protect the power system from damage. Excess power will be drawn from the backup batteries, which will cause them to slowly discharge. The system will alert the operator, and the operator can reduce altitude to reduce the power consumption, or land the drone and lighten the payload.
This guide has highlighted how the EON800 tether system works specifically with the Freefly Systems ALTA X. It's worth noting that the EON800 tether system can potentially integrate with other UAVs using a 12-cell lithium battery setup, as long as their power draw aligns with the limits of the EON800 System.
If you're considering integrating the EON800 with different aircraft, please reach out to us for more information. Our team is ready to discuss your unique application and requirements.
Technical Integration Contact: BD@XM2.com
Dimensions (Including covers)
560W 400D 250H (mm)
Weight
16.7kg
Input
200-250VAC, 47-63Hz, 30A Max
Output
800V DC 7.5A Max
Power Connector (AC Input)
powerCON NAC3MP-HC
Power Connector (DC Output)
Lemo 2S ERN.2S.302.CLL
Connectivity
Ethernet Port for Mavlink networking
SD Card Slot for Logging
User Interface
Colour Display with three button interface
Large Red Missile Style Switch for High Voltage Control
Display
2.8” IPS TFT LCD, 350cd/m2
Dimensions (In Travel Case)
560W 430D 210H (mm)
Dimensions (Installed on the Alta X)
450W 300D 135H (mm)
Weight (Installed on the Alta X)
2.85kg
Weight (Including Travel Case)
8.25kg
Input
800V DC
Output
46-50V DC 100A Max
Power Connector (HV DC Input)
Lemo 2S ERN.2S.302.CLL
Power Connector (DC Output)
3x Amass XT90 (recessed) – Patch Cables supplied to reach Aircraft
Power Connector (Battery Input)
2x Amass XT90 Panel Mounted, 2x JST-XH 6s balance ports
Fiber connector (External)
LC Simplex Fiber Connector
Connectivity
Fiber Optic for communication to TGS
Serial to flight controller via JST-GH 6 Pin
CAN-BUS for Integrated BMS
Mounting
Quick Release Push Pins to Alta X Battery Tray
Dimensions
400W 500H 300D (mm)
Standard Cable Length
Up to 150m (For flight up to 120m)
Weight (Cable, per m)
36 g per meter (±3 grams)
Conductors
18AWG – Rated for 1000V DC
Fibers
8x Singlemode LC Simplex
Fiber Speed
Up to 100 Gbps per core
