Onewheel DIY portable charger tutorial

This tutorial will help you to build your own Onewheel DIY portable charger. The DIY portable charger is capable of charging the Onewheel on the go.

In about 20min you are good to go for another session ūüôā With a large lipo you can charge the OW up multiple times.

Onewheel DIY portable charger
Onewheel DIY portable charger

You don’t own an Onewheel yet? Check out our Onewheel review.

Wanna see the charge in action. Watch our Onewheel movie on our Youtube channel.

Warning:

This project deals with electrical current and lipo batteries which can be very dangerous. Please read the tutorial completely and proceed cautiously.

1. Requirements and tools you need

  • Basic soldering skills
  • soldering station
  • screwdrivers
  • wire cutter
  • multimeter

2. Things you have to buy

Onewheel DIY portable charger: Things you have to buy
Onewheel DIY portable charger: Things you have to buy

2.1. Female XLR plug

You can easily find it everywhere on the internet ūüėČ

2.2. 2-wire power cord

You have probably such a cable laying around, 3 feet / 1m.

2.3. Boost converter module (400 Watt)

  • Aliexpress from China (US $ 6.33): link
  • eBay (US) from China (US $5.75): link
  • eBay (DE) from China (EUR 8,55): link

2.4. Case for the boost converter module

Module dimensions: 67x48x28mm/2.63×1.89×1.1 ”

  • You can use any case you want. Please make sure the heat sinks aren‚Äôt covered.
  • Free custom made 3D printable case on thingiverse: link

2.5. Battery:

Any 6S lipo battery pack with at least 6000 mAh (approximately 130 Wh)

  • Hobbyking (US): Multistar High Capacity 6S 8000mAh Multi-Rotor Lipo-Pack (US $77.18): link
  • Hobbyking (DE): Multistar High Capacity 6S 8000mAh Multi-Rotor Lipo-Pack (EUR 65.93): link
  • Coupling: when you buy one of the recommended battery packs you need a male XT90 jack. When you buy an¬†other battery you may need¬†another¬†coupling.

2.6. Lipo alarm buzzer

  • Hobbyking (US, US $4.19): link
  • Hobbyking (GER, EUR 3,91): link

2.7 6S lipo balance charger

You can use any 6s lipo balance charger you like. Here is a budget charger (charging takes a bit longer).

  • Hobbyking (US, US $29.99): link
  • Hobbyking (GER, EUR 21,35): link

2.8. Optional: Voltage display module

  • Aliexpress¬†from China (US $0.94): link
  • eBay (GER) from China (EUR 1,00): link
  • eBay (US) from China (US $1.39): link

3. Onewheel DIY portable charger – How does it work?

The original Onewheel charger converts 110-230V AC to¬†‚Čą58V DC and provide 3.5A.
So we have to build a power source which is capable of providing the same amount of current at the same voltage level.
Lipo batteries are a common power source which are perfect for our application. They are cheap and are available in many configurations.
You can find more information in our DIY electric skateboard article.
The Onewheel battery has a capacity of 130Wh. In order to charge the battery at least one time the lipo capacity must be higher than 130Wh. The 6S 8000mAh lipo provides¬†‚Čą¬†172Wh (6*3.6*8) which is suitable.¬†6S is the number of cells (full:¬†6*4.2¬†‚Čą¬†25V, nominal:¬†6*4.2 = 21.6V)
In order to get 58V to charge the Onewheel we need a boost converter which steps the voltage¬†up (25V¬†‚ÄĒ> 58V). The¬†boost converter is also capable of limiting the charging current to¬†3.5A.
Entire Onewheel charging setup
Entire charging setup – Battery, portable charger, cables + Onewheel

4. Soldering

  1. Take the power cord and cut it into two pieces (a short piece and a longer piece). Then strip all single wires at each end and make them nice with some solder.
  2. Take the XLR plug apart.
  3. Solder the minus wire (blue wire of the long piece) to pin 1. Use shrinking tube to isolate the pin.
  4. Solder the plus wire (brown wire of the long piece) to pin 2.
  5. Take a piece of wire and bridge pin 2 and pin 3 like on the picture.
  6. Before reassembling the plug make sure everything is soldered properly.
Onewheel DIY portable charger: XLR wiring
XLR wiring
Onewheel DIY charger: XLR wiring 2
XLR wiring – bridge between pin 2 & 3

 5. Wiring the boost converter module

Put the boost converter module into the case. When you use the 3D printed case the module will fit perfectly and it will stay in place.

  1. Take the XLR cable and strip the two wires at the other end. Now you can put it through the hole into the case. Make sure to connect the wire at the output terminal. Take also care of the correct polarity (plus: brown wire, red on the picture & minus: blue wire, black on the picture)
  2. Take the short piece of the power cord and connect the XT90 jack. Put the other end through hole into the case and screw the wo wires into the input terminal. For convenience we use the the same polarity (minus: blue wire, plus: brown wire)
  3. Optional: Voltage display: Take the red and the black wire of the display module and connect them to the input terminal. The white wire has to be connected to the plus pole of the output terminal.
Onewheel DIY charger: Inside of the case 1
Inside of the case – Input and output terminal

6. Adjust the output voltage

  1. Connect the (fully charged) battery pack to the boost converter via the XT90 connector. The voltage display should power up as well.
  2. Take a multimeter and measure the voltage at the output terminal. Use a small screw driver and adjust the voltage to 58.2V by using the voltage trimmer.
  3. The voltage display should show roughly the same voltage. You can adjust the display by using the mini trimmer on the back of the display. It should show 58.2V afterwards.
  4. Messure the voltage directly at the XLR plug and check the polarity once again (minus: pin 1, plus : pin 2 & 3) 
Onewheel DIY charger: Inside of the case 2
Inside of the case – Current and voltage trimmer
Onewheel DIY charger: Adjustment of the output voltage
Adjustment of the output voltage

7. Adjust the charging current

In order to do this the Onewheel battery must not be fully charged. Put the XLR plug into the OW charging port. Please go into the settings menu of the OneWheel app and check the charging current (at the end of the table). If is more than 4A use the current trimmer to decrease the charging current to 3.5A. If the charging current is less than 3.5A you can increase it.

Caution: The Onewheel DIY portable charger has no over discharge protection. That means we have to disconnect the battery manually¬†when it‚Äôs voltage level become low (‚Čą19.2V). Over discharge can be dangerous and it will damage the battery. For this reason it is advisable to use a lipo alarm buzzer. Please connect it to the balance connector of the battery every time you use the charger. After connecting it, it will beep and show the total voltage and the voltages of each cell. With the button please set the cell threshold voltage to 3.2V. If one of the 6 cells fall below 3.2V the lipo alarm starts beeping very loud. Now you must unplug the battery immediately and charge it with your lipo charger. Please note: the beeping is just a signal. The charging process is still continuing. Never leave the charging process unattended!

8. Onewheel DIY portable charger – Usage

Usage: Connect the lipo alarm buzzer with the 6S lipo battery pack. The voltage display should show¬†‚Čą58V. Now plug the XLR into the Onewheel or Onewheelplus charging port.

Voltage display: When you start the charging process the voltage display shows the voltage level of the Onewheel battery. It will increase gradually to 58V which means that the OneWheel is fully charged and you are ready to ride the next session 😃

If you have any questions about the Onewheel DIY portable charger feel free to write me an email: nico@e-boarder.com

We hope you liked our tutorial.

Cheers,
Nico

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