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A drone flying on tethered power. It is possible to stay in flight for hours or days.

Tethered drones fly forever.

The limiting factor on all electric aircraft is battery life. Even the best fly for less than an hour and many only manage 15 minutes. We've developed a low cost but high quality system that can keep your craft in the air all day.


Our tethered drone kit fits a large range of consumer craft and DIY frames as a direct replacement for the battery and turns it into a powerful semi-fixed aerial platform. Asides from the endurance improvement, the tether eliminates or reduces almost all health and safety concerns making it a perfect partner in dangerous environments for a professional pilot.

A single APU v2

A two APU stack with BBI and safety busbar covers

Backup Battery Interface

Drone and Battery Connections

The world's first drone tether kit:

Airborne Power Unit (APU)  v2                       $850

Tethered power systems give you the potential for unparalleled situational awareness. An enduring eye in the sky. Now even better with our version2 APU kit.


It’s $850 (shipped from the UK so we’ll add VAT tax for UK and EU customers)


If you can make the case to us that you’re going to use our system on a very worthy and good cause, we also offer a 10% “Drones for Good” discount.


The Airborne Power Unit (APU) Features:

  • Switchable high or low mode (either 3S & 4S or 5S & 6S equivalent voltage output).
  • Each APU can handle up to 500W comfortably (600W max)
  • You can stack upto 4 APUs together if you need more power:

    1 = 600W
    2 = 1200W
    3 = 1800W
    4 = 2400W


Just for reference, a DJI Phantom 3 uses approximately 150W to hover so a similar weight drone (say a F450 kit for example) with equivalent sized props would use similar. A F550 Hex with camera uses around 400W so for this setup we would advise using 2 APUs together to give you redundancy.


  • The APU needs an input of between 160V and 250V DC
  • Weighs 160g (5.64 ounces)
  • 175 x 50 x 35mm
  • Custom aluminum heat sinks
  • Stackable design for multiple APUs
  • Drone chassis mounting points
  • Optional cooling fan connection






Back up battery interface, a beautifully simple switching system that protects the drone should you lose ground power.


Simply add the BBI to the top of your stack of APUs and plug in a charged battery matching the voltage output of the APU (3S, 4S, 5S or 6S) and you can use it as an emergency landing capability, or drop the cable in flight and proceed on battery power alone. Either are possible.


XT90 connectors are fitted as standard for drone and battery connections.


Backup Battery Interface (BBI)                     $250

Example Base Power Units

We strongly recommend using a short length of protective PVC tube to protect the power cable from the props in take off and landings.

Base Power Unit (BPU)            $115 + China shipping

Every tether system needs a BPU of some description. In simplest terms it is a box that takes in mains electricity, generator, batteries, whatever power source you have... and outputs 160 - 250V DC (higher the voltage the lower the current and therefore the lighter the tether cable).


Do remember to install safety cut off fuses and take every measure to prevent electrocution should anything happen to the cable or drone whilst in use.


We recommend you source your own so that it works with your chosen setup. However we can provide you with some options for BPUs if you need.


Our current favorite is this low cost power unit from Yueqing Sense Group in Zhejiang, China.


Currently available in either 500W or 1000W outputs.


Dimensions:             262mm x 105mm x 65mm with adjustable voltage control.


It outputs a steady 250V under a range of load conditions and can reach a maximum of 500W which would suite one APU nicely. It's also excellent value and they ship quickly. Available to suit either 110V or 240V AC input.


To purchase:            Follow this ebay link


Or email:                   Jackson Qian on






Cable, we highly recommend a very high spec cable that is designed for the voltage and current you choose to use. Since the system runs on DC we use a shielded single core (which reduces tangling as there is less twisted tension in the cable) and run the negative down the cable shield.


Due to the power going through the system and for health and safety reasons, it's not advisable to have a long cable for low altitude flights, heat can build up inside a spooled cable or unspooled cables can cause people to trip. So perhaps have multiple interchangeable lengths for different applications.


We use AWG 26 cables for single APUs (running at 250V) but would recommend a thicker cable if you intend to operate more APUs together, or at a lower voltage.

Cable                     (Price dependent on length and gauge.)

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