Xiaomi M365

2 Articles

Xiaomi M365 Battery Fault? Just Remove A Capacitor

October 1, 2024 by 11 Comments

Electric scooters have long been a hacker’s friend, Xiaomi ones in particular – starting with M365, the Xiaomi scooter family has expanded a fair bit. They do have a weak spot, like many other devices – the battery, something you expect to wear out.

Let’s say, one day the scooter’s diagnostics app shows one section of the battery going way below 3 volts. Was it a sudden failure of one of the cells that brought the whole stage down? Or perhaps, water damage after a hastily assembled scooter? Now, what if you measure the stages with a multimeter and it turns out they are perfectly fine?

Turns out, it might just be a single capacitor’s fault. In a YouTube video, [darieee] tells us all about debugging a Xiaomi M365 battery with such a fault – a BQ76930 controller being responsible for measuring battery voltages. The BMS (Battery Management System) board has capacitors in parallel with the cells, and it appears that some of these capacitors can go faulty.

Are you experiencing this particular fault? It’s easy to check – measure the battery stages and see if the information checks out with the readings in your scooter monitoring app of choice. Could this be a mechanical failure mode for this poor MLCC? Or maybe, a bad batch of capacitors? One thing is clear, this case is worth learning from, adding this kind of failure to your collection of fun LiIon pack tidbits. This pack seems pretty hacker-friendly – other packs lock up when anything is amiss, like the Ryobi batteries do, overdue for someone to really spill their secrets!

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Put More Scoot In Yer Scooter

March 9, 2021 by 17 Comments

We have a scooter hack that is odd for a couple of reasons. First, the vehicle in question is a Doc Green EWA 6000, a German clone of a Xiaomi M365, so Country stereotypes be darned. Second, it is about increasing the performance, and when we think of scooters, we get hung up on scoot. The link between these peculiarities is the speed limiter Germany requires on all scooters, which the Chinese model lacks. Despite the law, [Nikolaj] wanted a higher top speed and Bluetooth connectivity. Wireless unlocks advanced features, like cruise control, which are absent in the stock model.

The mainboard is responsible for speed control, but that is merely a component, and you can find third-party replacements. [Nikolaj] found a new part with a German forum member’s help, then recorded his work in English for our sake. The speed boost is nice, but the Bluetooth functionality is a massive improvement by itself. If you live in an area where the law doesn’t allow this sort of thing, think before you upgrade. Aftermarket parts aren’t always drop-in replacements, and in this case, the controller and display needed some finessing to fit, so measure twice and buy once.

If tearing into a brand new scooter isn’t for you, consider breathing new life into a retiree, and don’t forget that stopping is the other half of the battle.