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.
The TSDZ2 with open-source firmware can run on packs as low as 24V, so you could use only 7 cells, or something only slightly larger than the common power-tool battery. I wouldn’t bet on it being very useful (the motors expect 36-48V), but I don’t think this was the point here :)
I just got one of those kits, which firmware are you talking about?
https://github.com/OpenSourceEBike/TSDZ2_wiki/wiki
https://github.com/emmebrusa/TSDZ2-Smart-EBike-1
I’ve installed it a few years ago though, and I can’t tell if this is still compatible with today’s TSDZ2. I think they had changed the MCU at some point.
Posted 2 weeks ago to YouTube so he should probably expect a registered letter with a C&D from the IP lawyers at Berkshire Hathaway any day now.
They own Duracell.
Normally, as a lawyer who works with makers (but NOT an IP lawyer), I’d say “who cares, it’s a hobby thing, ‘confusion or dilution’ is a stupid worry. BUT this guy has 1.2 M followers.
And yeah, IP law is mostly idiotic — I’m guessing a C&D for this guy while OpenAI gets billions to steal real individual work … late stage capitalism … whatever the ‘f that is …
FWIW, Duracell batteries nowadays are the absolute worst sheit there is. They puke all over your device in less than 2 years.
First of all it isn’t named duracell, but more importantly, he does not run a business selling batteries does he? So there is no case to be made. And if a lawyer doesn’t get that… oh dear.
I’m no employer but I think that if you are employed as a lawyer you can expect a termination notice any day now.
Actually, Antti is right. Look up trademark infringement.
Correction: Titus431 is correct. (Antti is correct, too, but that’s the point I was trying to make.)
Hmmm … thanks for the thoughtful feedback, but let me try to put it another way.
BIG COMPANIES TEND TO BE VERY PROTECTIVE OF THEIR BRAND, EVEN WHEN WHAT YOU’RE DOING ISN’T REALLY A THREAT.
MAKING SOMETHING THAT INTENTIONALLY LOOKS AND IS LABELLED LIKE A BIG COMPANY’S PRODUCT WILL GET YOU UNWELCOME ATTENTION, ESPECIALLY IF YOU ARE MAKING MONEY FROM WHAT YOU’RE DOING.
THIS ISN’T GOOD OR RIGHT BUT MORE AN ABUSE OF A BROKEN INTELLECTUAL PROPERTY FRAMEWORK THAT FAVORS LARGE AND WEALTHY COMPANIES.
THIS IS A BAD THING — IF YOU COPY A BIG BRANDS LOOK, THE BIG COMPANIES WILL GET MAD. AND, NO, CLAIMING FAIR USE WILL NOT SAVE YOU UNLESS YOU ALSO HAVE ACCESS TO UNLIMITED FUNDS OR LAWYERS.
Better?
That’s not how court works.
Which is why he will repaint the battery and remake the video.
The process is the punishment.
He can’t afford the process and Duracell knows it.
Duracell has enough of a case to bankrupt him, it is a battery, in their paint scheme with a logo on it that might confuse a full idiot.
But they will likely ‘go nice’ first.
Their lawyers will say they ‘have to defend the trademark’.
I’ve told clients they ‘had to’ do things involving paying me before, mixed results.
It’s clearly a parody, which is protected speech, but they might sue the pants off him anyway. That’s his deal, though, not ours.
I’m honestly surprised that this went a legal direction when there are totally reasonable nits to pick with his battery construction. Hackaday commenteers, you’re letting me down!
Cells only held together with welds and tape (and hope) in a high-vibration environment. Insufficient protection of the wires from the tabs, so the insulation could wear through and short. (Keyword: fishpaper) Spot welds look kinda sketchy/light for the current he’s going to be drawing; I would have done two or three pairs per tab.
https://hackaday.com/2019/06/12/an-exhaustive-guide-to-building-18650-packs/
It will need rebuilding in a while, and hopefully doesn’t catch anything on fire before it does. But meh, it’s on a bike, and it’s a first attempt. It’s not like it’s down in his basement with the oil-soaked rags.
And I’ve done worse. But none of you have ever seen it.
And surely that is a terrible oversight by you and your writing colleagues – a nice article on doing a sloppy job and presumably getting away with it.
Honestly given the nature of this battery I don’t think the nits to pick really matter – could it be better yes, but he knows it so will treat it with the caution it deserves, unlike the thousands of Chinesium hoverboard etc owners that ignorant with probably worse battery… It is also a very small battery which limits the risks.
Throw away content for youtube subscribers::
Make pack.
Make revenue.
Throw away pack.
Move on to next video.
Rinse and repeat.
Who cares if it’s badly made? None of his subscribers.
I don’t know why it would be “late stage”. You can get there without every having free markets. More like a mix of free markets and lawlessness or selective law, which are not compatible.
I have a little Brompton fold-up bicycle that I DIY converted to an electric bike, and it uses a power tool battery, albeit a 36V one (I swap the battery between bike and lawnmower). No charger issues as I already had one. I haven’t taken it on a flight but I have taken it on trains and stored it in the gap between seat backs.
There are a few technical benefits to this idea, especially if you use multiple of the packs in parallel.
One major benefit is granular control of the battery management. A single bad cell can’t stop you, and may be eaiser to repair. But at the very least you can replace one smaller pack instead of a larger pack with teamed series cells.
The 100 Wh isn’t as bad as you might think if you are allowed multiple batteries.
Check out what Dennis Palatov is doing with his AWD EV project and Cascadia Motion. Similar concept with multiple small higher voltage packs, added in parallel until it can supply just what’s needed to reach your performance or range needs.
Also he could take the same idea and move up to a 21700 cell, which isn’t that much bigger (IE would probably still fit) but could carry more power.
I could be wrong, but he may need to move to pouch cells to get the highest power density, at which point making the BMS/Protection circuit smaller and designing a sturdy case to keep them compressed under high draw would probably be your biggest problems.
Excellent hack BTW 👍🏼
I should say also that depending on his maximum power draw he might want to look into a phase change sleeve for thermal management, I had a lawn tool pack that did that. The power density is so small it could help if there was a long time allowed between cycles, IE not fast charging and swapping them, but allowing a long cool down.
“this tiny… batty”
Ali G would have a field day with that
I have 100Wh LiFePO4 battery on kid’s bike (needs to be lightweight), that gives 30+ km in summer.
Biggest issue is series resistance and maximum discharge current, that does limit the assist power on climbs a bit. Not an issue for a lightweight rider, but on an adult’s bike I could see that being annoying.
Or, perhaps YOU look up trademark infringement.
Alternatively you can type in all caps and convince yourself you are right.
If that fails you can make a picture with the text and post that, on the internet that is seen as some sort of proof.
And if even that fails there is always vicodin and fentanyl right?
Thanks HAD, thanks a whole freaking lot, great job not making my reply a reply, great job, really, you should pat yourself on the back for that hack. Another day another hack.
Don’t build a battery like he did unless you want a fire. The wrapper the cells come with is very thin and not a suitable insulator, especially when there is vibration involved. There are a lot of places that could rub through and short out.
Use plastic spacers between the cells, put insulator rings around the positive terminals and cover the tab strips with adhesive fish paper. Since the battery is supplying a lot of current, the tabs should have multiple welds too.
Going for a ride in the forest full of dead leaves with a overheating home-made Lithium battery… what can go wrong ?
I have a strip of tape that I took out of a big name laptop battery. It’s stuck on the shelf edge right in front of me. It’s green thin plastic and has 4 chinese characters and most of the word FRESH.
Batteries bound up like broccoli, wow! Green lithium ion bunched on-ions, you’ll cry tears.