Erguro's Tello Mini Drone Lipo Battery Caddy

Hi everyone!

Tello is a amazing and good quality small drone from ryzerobotics company in cooperation with DJI

This instructable consists of modifying a broken, puffy original battery from a Tello drone to be able to use normal LiPo batteries.

To do this, we will eliminate the internal cell of the original FullyMax battery, keeping the charging board that goes inside the battery and adding a connector to be able to use normal LIPo batteries.

One FullyMax Original Battery costs about 25€. Five not original LiPo Batteries cost about 36€ more or less 7€ each, so this hack it´s a great deal !

You will need:

• A broken or puffy original FullyMax battery 1100mAh
• LiPo 3,7V 1S 1000mAh 25C 5x Pack
• PCB Pin strip
• Sharp Knife
• Hot glue gun 200w mínimum
• 11 W soldering iron JBC Recommendend
• Free Lead tin solder wire
• FACOM Good quality Pliers

As you can see at the pictures, in this case my original battery was inflated after only 12 charge cycles.

The original FullyMax battery is rated at 1100mAh @3,8V max charging Voltage 4,35V usually LiPo batteries charge just to 4,2V so this additional 0,15V could be a problem, in my experience I didn´t notice after 5 charge cycles.

Open the plastic shell cutting along using a sharp knife or "cutter"

The most important thing is the charge and protection small board, please remove it carefully using a JBC low power 11w ironing solder or similar, adding some new free lead tin solder wires to the pads, will help melting old tin.

When you dissambly the original FullyMax battery shell, you get 2 plastic pieces, up and down, you have to left 15mm flange in the downside piece and cut the rest (as you can see at the pictures) in the upper side you cut a 15mm piece.

Get the normal LiPo battery connector and solder to the original protection board, respect the polarity according to pictures. You will see B+ and B- labeled in the small protection board

Joint together the 2 shell cutted plastic pieces with a piece of electrical tape and fill with hot glue

wait until glue is cold and remove electric plastic tape

Your Tello´s LiPo battery caddy is done !!

I choose this 1000mAh LiPo because size compatible with Tello and is a 25C discharge bat, all LiPo's comes with a small protection board to avoid deep discharge and short circuit, in this case you have to remove this protection board because you will use original FullyMax protection board. (remember mark positive and negative terminals)

Next step is bend 2 Pcb board pins with the help of pliers

Solder this pins to the battery (remember you have to remove LiPo protection board)

You can connect the battery to the caddy

First of all you have to remove white plastic top cover of Tello mini drone, no screws just plastic pressure clips, quite easy to remove using a spudger or flat small screwdriver.

Then slice the new battery caddy

Connect microusb charger led will start blinkig in blue, when led stop blinking (fixed blue) your battery is ready to fly.

Congratullations!!!

Enjoy flying with all the batteries you want at an unbeatable price !