How to Make a Fiido D4S Battery (kind Of) Removable

Do you guys have a Fiido D4S but not a place to charge it?

You know, your house is too small to place a bike or simply you don’t have electricity in the garage?

If this is your situation, don’t worry, I feel you!

I know what you are thinking! Another article with a lot of incredible tool I don’t have.

No, this is not that type of article! I just want to share with you my experience with this project and maybe I can help you to do that too.

So, let’s start! At the end of this project you will be able to take apart your battery whenever you want and go to charge it at the nearest power socket.

We will make the cables shorter to insert the battery more easily and we will 3D print a new external plate (if you don’t have a 3d printer, don’t worry, I will explain you how to build a similar thing without it) and that’s it!

Obviously to remove the battery every time you back home, you will not need a screwdriver or something like that, you just need you hand.

You can read this article also here

Soldering iron

Tin

Stinking tube

White pen

cable ties

insulating tape

vice

cutter

Phillips screwdriver

3d printer (optional)

Various tool

First of all we need to 3D print a new plate to automatically center the plate when we fold the bike.

With this new plate, before closing the bike, we can insert the battery into the slot and position the plate without letting it fall out of the slot thanks to the small pieces of plastic that act as springs on the outer walls of the slot.

When we open the bike, we will find the plate attached to the other side of the plate (the male one) and now we can simply remove it with our fingers.

here you can find the file to print it in 3d

If you don't have a 3d printer, you can make that just with some metal plates and super glue or some springs taken from clothespins.

There are a thousand ways to do it, be creative!

As you know, 3D printed parts are very very strong in all directions except that of the layers.

For printing needs I had to print it in the direction you see in the last photo but in this way the tabs that have to move are very fragile.

So, I thought about soldering the layers together. This way you can have the same strength on all sides.

First of all, you will need a soldering iron and then, you will need to gently touch the surface of the plastic tabs with the tip of the soldering iron.

You will have to do it both ways (I recommend twice). Eventually you will see something like the one in the picture.

And now you can try ... I mean, seriously, you can try to break it but you can't.

Okay, now that you have the brand new plate, you can get started with the electric stuff!

If you see, in the original plate there were two screws: two to attach the plate to the slot and the other two to attach the contact plate to the metal plate.

You just need a large and a smaller screwdriver to unscrew the battery contact from its positions.

Behind the contact you will find hot glue (as you see in the photo) that you will remove to remove the contacts from its plate.

Now that you have the red and black metal contacts you must be careful not to touch the two wires so as not to cause a short circuit.

Yes, it is not necessary to do this step, but it is highly recommended to shorten the wires to make it easier to insert the new 3D printed plate into the battery slot.

For this reason it is necessary to cut the wires 10 centimeters and remove the connectors (which take up space). Of course please don't cut the red and black wire at the same time with the same scissors as you will cause a short circuit, even with the Battery Management System.

Now that you have the shorter wire, solder it to the metal contact well because the wire will carry 6 Amps (250W / 42V) and use heat shrink tubing to insulate it.

Now that you are done with the RED wire, place the contact in place and do the same with the black one. Always use tape to insulate the red wire from the black one, and don't do the process with both wires at the same time.

As you can imagine from the last step, you will do the same with the smaller charger connector

This is very simple: with a screwdriver, unclip the pins from the charger connector by inserting the screwdriver into the side hole of the connector. Once unhooked, take them out.

Now you can simply cut the wires to 10 centimeters and isolate one of them. Now open the clips pressing on the wire and cut the wire as close as possible to the metal contact of the connector.

Now take the soldering iron and solder the wires to the metal contact of the connector and reinsert it into the plastic connector. (I used some glue because I broke the metal tab that was holding it in place).

Do the same with the other wire.

After doing all the steps, it will now be much easier to remove the battery and take it to charge at the nearest outlet (as you can see from the video).

Also, you can add a small handle made with scotch tape (as you see in the photo). Thank you for reading the article