HMP Lightning MK II: What’s Wrong With Dianmu’s Battery?
From Transport Evolved.
Watch this video on YouTube ↗
Back at the start of October, Nikki dropped by the headquarters of HMP Bikes in San Francisco to swap out her HMP Lightning MK II's removable battery, after it decided to play Possum. Replacing it with a known-good pack, she was able to take her bike - Dianmu - out for a few trips.
But just two days after making a trip, she came out to find her bike's battery doing exactly the same thing as the first: powering on the bike, but with the BMS refusing to play ball. And without a functioning BMS, Nikki's bike was effectively dead in the water.
Reaching back out to HMP Bikes, she thinks she has the fault tracked down: a faulty BMS board that's already been redesigned and is winging its way to her. Ordinarily, a replacement like that would be something for the technicians to do - but Nikki's been given special permission to open her battery up using safe battery handling techniques - just to see if there's anything awry she can spot.
In today's video, join Nikki as she opens up the battery, measures the cell voltages - and makes a very important mistake that proves why you should always double-check your readings (and your logic) when reverse-engineering or carrying out DIY repair.
The replacement boards are on the way to us - so keep your eyes peeled for part 2!
Full shownotes, links, and transcript at: https://www.transportevolved.com/2026/11/10/hmp-lightning-mk-ii-whats-wrong-with-dianmus-battery/
----
*⏱️ Chapter Breakdown*:
00:00 - Introduction
01:58 - Symptoms
06:01 - Letting HMP know - and getting permission to open it up
08:08 - Checking the Voltage
10:29 - Opening up the battery
13:20 - Testing the fuse and cell voltages
15:12 - Trust - But Verify!
20:13 - Thanks, and goodbye!
📺 More from our HMP Lightning Mk II:
▶️ Possum Battery: Our HMP Lightning MK II Played Dead. Here's Our Fix - https://youtu.be/Axhm4FkG0Ck
▶️ 500 Miles In - Our HMP Lightning Mk II Is Proving Itself Very Useful! - https://youtu.be/LoVm8yvbecc
▶️ Nikki's Got ANOTHER Lightning — Meet the HMP Electric Motorcycle - https://youtu.be/T-QmgS7GtMo
*🔗 Links*
🔗 HMP Bikes - https://www.hmpbikes.com
🔗 The HMP Lightning MK II - https://www.hmpbikes.com/products/lightning-mkii-electric-motorcycle
----
*👥 Today’s Sponsors*
🌱 Electric Vehicle Association - https://www.myeva.org
🐕 Little Collie Shepherd - https://littlecollie.com
—
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---
*🎙️ Credits:*
Host, Producer: Nikki Gordon-Bloomfield
Camera, Editor, Color: Vi Horton
Thumbnail: Erin Carlie
Music: "Love Letters" by warmkeys., via Artlist.io - https://artlist.io
Music: "Peer Gynt - In the Hall of the Mountain King" (Edvard Grieg) by Kashido, via Artlist.io - https://artlist.io
Music: "Got It" (Instrumental Version) by VESHZA, via Artlist.io - https://artlist.io/royalty-free-music/song/got-it-instrumental-version/11284
But just two days after making a trip, she came out to find her bike's battery doing exactly the same thing as the first: powering on the bike, but with the BMS refusing to play ball. And without a functioning BMS, Nikki's bike was effectively dead in the water.
Reaching back out to HMP Bikes, she thinks she has the fault tracked down: a faulty BMS board that's already been redesigned and is winging its way to her. Ordinarily, a replacement like that would be something for the technicians to do - but Nikki's been given special permission to open her battery up using safe battery handling techniques - just to see if there's anything awry she can spot.
In today's video, join Nikki as she opens up the battery, measures the cell voltages - and makes a very important mistake that proves why you should always double-check your readings (and your logic) when reverse-engineering or carrying out DIY repair.
The replacement boards are on the way to us - so keep your eyes peeled for part 2!
Full shownotes, links, and transcript at: https://www.transportevolved.com/2026/11/10/hmp-lightning-mk-ii-whats-wrong-with-dianmus-battery/
----
*⏱️ Chapter Breakdown*:
00:00 - Introduction
01:58 - Symptoms
06:01 - Letting HMP know - and getting permission to open it up
08:08 - Checking the Voltage
10:29 - Opening up the battery
13:20 - Testing the fuse and cell voltages
15:12 - Trust - But Verify!
20:13 - Thanks, and goodbye!
📺 More from our HMP Lightning Mk II:
▶️ Possum Battery: Our HMP Lightning MK II Played Dead. Here's Our Fix - https://youtu.be/Axhm4FkG0Ck
▶️ 500 Miles In - Our HMP Lightning Mk II Is Proving Itself Very Useful! - https://youtu.be/LoVm8yvbecc
▶️ Nikki's Got ANOTHER Lightning — Meet the HMP Electric Motorcycle - https://youtu.be/T-QmgS7GtMo
*🔗 Links*
🔗 HMP Bikes - https://www.hmpbikes.com
🔗 The HMP Lightning MK II - https://www.hmpbikes.com/products/lightning-mkii-electric-motorcycle
----
*👥 Today’s Sponsors*
🌱 Electric Vehicle Association - https://www.myeva.org
🐕 Little Collie Shepherd - https://littlecollie.com
—
✊ Get Involved 🗳️ https://indivisible.org/town-hall-resources
❤️ Support the Show
📰 https://www.transportevolved.com
🔥 https://www.patreon.com/transportevolved
☕ https://ko-fi.com/transportevolved
📺 https://www.youtube.com/transportevolved
👕 https://www.redbubble.com/people/TransportEVd/
🛍️ https://amzn.to/40xOyjm
₿ BC1QRZRGCCXUKPDZ2DZ9KX9JYJXMZDYHYGFZ0MN4WH
*💬 Join the Conversation*
🐘 https://mastodon.transportevolved.com/@show
💬 https://discord.gg/9WAjfQn
💬 https://fluxer.gg/mcj8aehg
🌀 https://bsky.app/profile/transportevolved.bsky.social
🧵 https://www.threads.com/@transportevolved
📸 https://www.instagram.com/transportevolved
🔁 Subscribe to our 2nd channel - https://www.youtube.com/transportevolvedtake2
---
*🎙️ Credits:*
Host, Producer: Nikki Gordon-Bloomfield
Camera, Editor, Color: Vi Horton
Thumbnail: Erin Carlie
Music: "Love Letters" by warmkeys., via Artlist.io - https://artlist.io
Music: "Peer Gynt - In the Hall of the Mountain King" (Edvard Grieg) by Kashido, via Artlist.io - https://artlist.io
Music: "Got It" (Instrumental Version) by VESHZA, via Artlist.io - https://artlist.io/royalty-free-music/song/got-it-instrumental-version/11284
