Making the World’s Smallest E-Bike Battery
Often times, e-bikes seek to build the biggest battery with the most range. But what if you want to take a couple lunch loops on your bike and only need 20 minutes of charge? That’s [Seth] from Berm Peak set out to find out with his minuscule Bermacell battery.
The battery is made from only 14 18650s, this tiny 52V batty is nearly as small an e-bike battery as can be made. Each cell is 3000 mAh making a total battery capacity of 156 Wh. All the cells were welded in series with an off the shelf BMS and everything was neatly packaged in an over-sized 3D printed 9V battery case. [Seth] plans to make another smaller battery with less then 100 Wh of capacity so he can take it on a plane, so stay tuned for more coverage!
[Seth] hooked up the Bermacell to the Bimotal e-bike conversion system on his trail bike and hit Kanuga bike park. He got three laps out of the Bermacell, and thinks a fourth is possible with more conservative throttle usage. The three laps equates to about 1500 ft of total elevation gain, a metric commonly used by mountain bikers. For a more useful metric for commuters, [Seth] recharged the battery and rode to a nearby coffee shop and back, a distance of nearly 13 miles with pedaling and throttle assist.
This is not the first time we have seen [Seth] hacking on e-bikes. Make sure to check out our coverage of his jailbreak of a pay to ride e-bike.
hackaday.com/2025/09/01/making…
