Indoor Bike Improvement #2 - USB Upgrade

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 2 of 10 - Improved USB Power 

The SB20 smart bike was introduced 4 years ago with a pair of built-in USB-A ports. The intent was to give you USB power for phone charging or adding a tablet. The total power for both ports is 5 watts (2.5 watts for each port).

Welcome to late 2023. USB at 2.5 watts will not charge many devices. An iPad can actually discharge if plugged into to a built-in port.

What's Inside?

Beneath the SB20's phone tray is a triangular circuit board for a switching power supply.  It takes 24 volts from the bike's main power brick and converts it to three 5 volt USB outputs. 


Extra USB port?

Wait a minute. The SB20 has two built-in USB ports. Why the extra USB output?  The beefy power supply circuit board suggests that Stages had plans for an additional device. My guess: the SB20 was supposed to have a screen for gear display. It was likely deleted early in the product development lifecycle. 

For those who want to optimize SB20 power consumption, you can safely disconnect this circuit board.  It reduces SB20 power requirements by about 1 amp. In a future post, I'll share what I put in the space formerly occupied by the circuit board.

120 Watt External Charger

To power my two iPads, Garmin computer and phone charger, I added an external power supply / charger. This let's me power multiple high current devices while also charging them when the bike itself is turned off.



Requirements: iPads need up to 50W when running graphics-intensive applications like Zwift. For wattage above 5W, you need USB-C power supply outputs. After trying smaller 60W and 90W chargers, I settled on a 120W charger with 2 USB-C and 2 USB-A ports.

Power Cable Conduits

The USB-C lightning cables for my iPads plus the USB-A cables for my other devices are routed in plastic conduit that runs up the side of my bike.




I also added an aluminum box channel to route the main 24V power supply cable to the back of the bike.  These conduits effectively hide all power cables. 

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