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Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
@DrAzzy
It sounds like you're not providing an appropriate voltage for the motors; if you say it came with 4xAA battery pack (6v) - I'd assume that's the voltage the motors are meant to be run at.
On USB power, it would be getting 4.3v (there's a diode on the 5v), and on a 1S lipo, around 3.7v - This would explain the low torque you're observing. Run it off a battery pack (connected to the battery connector) that supplies around 6v, and it should perform much better. Since you want to use a rechargable LiPo battery, I'd be inclined to use a boost converter to step it up to the desired voltage - you can get them on ebay for dirt cheap.