Illustration: How to Know When a Tello Drone Is Fully Charged – SwellRC RC Drones guide

How to Know When a Tello Drone Is Fully Charged: Light Codes Explained

RC Drones

When charging a Tello in the drone (switched off, via micro-USB), the status light blinks slowly while charging and turns solid when the battery is full; fast blinking means a charging error. On the official charging hub, a blinking green light means that battery is charging, solid green means it’s finished, solid orange means it’s waiting its turn, and solid red indicates a faulty battery. The Tello app also shows the battery percentage once you connect.

Updated: October 20264 min read

Illustration: Tello drone charging indicator light – SwellRC RC Drones guide

Charging in the drone

Light Meaning
Blinking slowly Charging
Solid Fully charged
Blinking quickly Charging error

The drone must be switched off for charging to work this way.

Charging on the hub

Light Meaning
Blinking green Charging normally
Solid green Charging finished
Solid orange Waiting to charge
Solid red Battery fault

The hub charges batteries one at a time, starting with the one at the highest voltage, so expect one slot to finish before the next begins. Charging methods and times are covered in how to charge a Tello drone.

Checking in the app

After charging, switch on the Tello and connect your phone to its Wi-Fi; the app shows the battery percentage on screen. If it reads less than 100% right after charging, the battery may be ageing or the charge stopped early. Connection steps are in how to connect a Tello to Wi-Fi.

If you see an error

  1. Unplug and reseat the battery firmly.
  2. Try a different USB cable and a 5 V adapter of at least 1–2 A.
  3. Let a hot battery cool to room temperature and try again.
  4. If the fast blinking or red light continues, the battery may be faulty; replace it.

How long it takes

Charging time depends on the adapter and how empty the battery is. In the drone with a good adapter, expect roughly an hour to an hour and a half. The hub, with a 5 V / 2 A adapter, takes about two hours for three batteries.

Battery care

  • Don’t charge immediately after flying while the battery is warm.
  • Unplug once charged rather than leaving it for days.
  • Store partly charged if unused for weeks.
  • Replace swollen batteries.
  • Charge on a non-flammable surface and stay nearby.

Signs of an ageing battery

Shorter flights, the percentage dropping quickly during flight, or the battery not reaching full charge all mean the battery is wearing out. Tello batteries are consumables; rotating two or three spares spreads the wear and gives you more flying time per session.

Before each flight

Even with a solid “full” light, check the percentage in the app after connecting. A battery that shows full but drops quickly in the first minute of flight is worn and should be replaced. Warm batteries also read differently from cold ones, so let them reach room temperature before judging. In cold weather, keep spare batteries in a pocket so they stay warm, since cold LiPo cells deliver less power and the Tello may warn early or land.

Managing several batteries

Number your batteries and use them in rotation, so they wear evenly. Note when each one starts giving shorter flights. With the hub, put the fullest batteries in first if you want one ready quickly; the hub charges the highest-voltage battery first.

FAQ

What colour is the Tello when fully charged?

The light goes solid when charging in the drone; solid green on the hub.

Why is my Tello light blinking fast while charging?

It indicates a charging error; check cable, adapter and battery.

Does the Tello charge while switched on?

Switch it off to charge.

What does orange on the hub mean?

That battery is waiting its turn.

More on this topic: the complete RC Drones guide covers the basics behind this article.

Kyle Hilson, author of SwellRC

About the author: Kyle Hilson

About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC