I Donut Believe, Episode 4: Failure Mode
- Buck City Biker
- 1 day ago
- 2 min read
The latest instalment in the Donut saga is here, and this one builds on the VTT programme we’ve been tracking from the start.
Up to now, the focus has been on charging speed, thermal behaviour and real-world pack performance. This latest test shifts the spotlight onto safety, specifically, how the cell behaves after it’s already been damaged.
That’s the angle in the latest “I Donut Believe” video. Donut handed VTT the same pouch cell damaged in the earlier high-temperature test, where the pouch had already lost its vacuum seal. From there, the question was pretty straightforward: when this cell fails, will it fail violently?
Key Takeaways from the Safety Demonstration Test
This was a damaged cell, not a clean one. VTT tested the same 26Ah pouch cell that had already been compromised during the earlier heat test, after the pouch lost its vacuum.
VTT pushed it through repeat cycling anyway. The test programme included five 1C cycles and 50 fast-charge cycles at 5C on that damaged cell.
No fire, no thermal runaway. That’s the headline. Across the test, Donut says there were no temperature spikes and no fire risk, despite the damaged condition.
Performance definitely took a hit. External reporting says capacity fell from around 24.7Ah to 11.2Ah, with lower efficiency and increased cell thickness. So this wasn’t a case of a damaged battery carrying on like nothing happened.
What matters is the way it failed. Donut is clearly trying to show that even when compromised, the cell degrades and throws an error rather than turning into a fire event.
The BCB Take
This is one of the more interesting Donut tests so far, because this time the story isn’t really performance. It’s failure.
For motorcyclists, that matters. Fast charging is great. Big energy density claims grab our attention. But if you’re putting a pack between your knees, graceful failure is a big deal.
This test does not show a damaged battery carrying on as normal. The cell took a serious performance hit, and that’s part of the story too. What Donut has shown is narrower than the headline might suggest, but still worth noting: once the cell was already compromised, it didn’t go bang.
Ride safe, folks.
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Watch The Video
Download the VTT test documentation here.
