Video Interview with Justin - Grin Technologies

Ravi Kempaiah

Well-Known Member
This is an excellent video..!
@Court has done a terrific job and he is organizing E-bike knowledge in a truly wonderful way. Way to go man.

Now, Justin is an E-bike celebrity. He along with few others started the DIY E-bike revolution and revived a forum called "Endless Sphere". He doesn't need much introduction.
It's a LONG video but worth it. They talk about batteries, motors, BMS, Electric Skateboards and what not...
Takes you right into the heart of DIY cauldron. Enjoy.

 
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Bike_On

Well-Known Member
This is an excellent video..!
@Court has done a terrific job and he is organizing E-bike knowledge in a truly wonderful way. Way to go man.

Now, Justin is an E-bike celebrity. He along with few others started the DIY E-bike revolution and revived a forum called "Endless Sphere". He doesn't need much introduction.
It's a LONG video but worth it. They talk about batteries, motors, BMS, Electric Skateboards and what not...
Takes you right into the heart of DIY cauldron. Enjoy.

This is a great interview. I am watching it now. I have bought his stuff for several years, dialoged with him on technical issues, discussed issues on ES forum. Justin is a Pioneer in Ebikes.

If you did not notice, his "sweet spot" in commuting is 1000-1200W. That is real -world experience. That shows the unfortunate disconnect between US laws and OEM offerings, and what real-world needs will be for critical mass ebikes.
 

irenewg13

Active Member
I sent this conversation to my son-in-law, he is seriously into biking, and skating. He commutes daily to work, pretty much year round.
When I bought the EM street, he was of course interested. I sent him some diy sites.
He's going to love this video.
We have an expression in our family, "road trip" !!, when find out about some place fun. My subject on this email to him, was Road Trip... Vancouver.
 

Ravi Kempaiah

Well-Known Member
There is so much to learn from people like Justin.
His wind tunnel idea was genius. Also, the way he tried to replicate DD hub weighing close to a geared hub, super heavy duty lights etc.
I agree @Bike_On , to make any commuting practical 25-28mph and 1000W (well, not continuous!) is optimal.
I am glad there are people like Justin who enable and empower other DIY enthusiasts with products like CA-V3, Satiator, E-bike motors etc.
Re: laws, it is what it is. Thank god we don't have the EU laws.

@irenewg13 , that's awesome. A summer vacation in Vancouver!
I lived in Canada for two years and Banff/Jasper national park area is the most beautiful/most scenic place I have been to so far. Vancouver is very beautiful too. Whistler is THE place for mountain biking. Your SIL is going to love it.
 

Bike_On

Well-Known Member
I finished up watching the interview. This guy is so knowledgeable, smart, and has a great attitude. I talk geek, so I am mesmerized over the ideas.

I have heard that Justin has a Falco motor up there, but I have not seen it show up in the simulator selection.

Court - did you see it by chance?

I am curious if he could support or disprove some of the Falco claims for their 5 phase motor: more efficient, less cogging.

Also, I have one of their epoxy 8-LED lights. It is extra wiring to get it from the battery, but they are very bright!
 
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Bike_On

Well-Known Member
Fun banter on mid-drive vs dd drive efficiency. He likes measured results. I need to send him some comparisons I have using the CA. I have 4 years of data on a mid-drive Optibike and 2 years now on a DD Drive Falco. Unfortunately, they are different commute routes and experience a bit different terrain and stop/go.
 

Ravi Kempaiah

Well-Known Member
I finished up watching the interview. This guy is so knowledgeable, smart, and has a great attitude. I talk geek, so I am mesmerized over the ideas.
I have heard that Justin has a Falco motor up there, but I have not seen it show up in the simulator selection.
Court - did you see it by chance?
I am curious if he could support or disprove some of the Falco claims for their 5 phase motor: more efficient, less cogging.
Also, I have one of their epoxy 8-LED lights. It is extra wiring to get it from the battery, but they are very bright!

He is certainly a pioneer when it comes to E-bikes. I have a documentary about his tour to China. Send me your email ID and I will send you the link.
Endless Sphere has some great info re: the following but it gets buried because of lack of organization....

8 pole motor Vs 12 or 16 pole motors and what manufacturers use what kind of motor!
# of stator magnets and it's effect of torque
Stator width Vs torque
3 phase Vs 5 phase

These topics have been discussed at length already....
 

Cameron Newland

Well-Known Member
This is a great video. I learned a lot about batteries. I had heard that it's best to keep your batteries between 20% and 80% to give them a longer cycle life, but I didn't know that the 0%-20% portion of the battery could be safely used/discharged without noticeably affecting cycle life.

And it's good to know that you should make sure to give your batteries a full charge every so often so that they're better balanced, as your BMS only balances the cells when it fully charges the pack. I had assumed that this was the case but I hadn't really thought about it until I watched the video.

The craziest thing about the video was the Lego battery pack. That could be a real revolution for ebikes. I've always wondered why ebikes don't have a standard, interchangeable battery design. Obviously part of the reason is that there are different cells and packs for different uses, and some companies might patent certain particularly innovative pack designs, however, the consumer really has an interest in having a standard design like the Lego battery pack so that we can easily ship batteries without doing hazardous materials shipping, and also to make it easier and cheaper to replace damaged or misbehaving cells. That's a total game-changer.
 

irenewg13

Active Member
I'm going to have to watch the video, again.
Cameron, I need some further explanation re...
"And it's good to know that you should make sure to give your batteries a full charge
every so often so that they're better balanced, as your BMS only balances the cells when it fully charges the pack."


And, what is BMS?

Thanks.
Irene

Ravi, I would like to see the China documentary.
 

Ravi Kempaiah

Well-Known Member
I'm going to have to watch the video, again.
Cameron, I need some further explanation re...
"And it's good to know that you should make sure to give your batteries a full charge
every so often so that they're better balanced, as your BMS only balances the cells when it fully charges the pack."


And, what is BMS?

Thanks.
Irene

Hi Irene,

Imagine a large group of ants carrying a heavy object. We gotta admire their coordination and skill to do such a thing. Each ant contributes in a positive way and together they are able to lift a weight that is almost 100 times their weight.

Similarly, the battery packs in our bikes have several individual cells that work in unison to give sufficient power to propel us.

Each cell can provide voltage between 3.0V(empty) to 4.2V (charged). You stack them up in different series/parallel configuration and you get 36V or 48V (most of our bikes are 36V).



But just like the amazing coordination of ants, the role of BMS (battery management system) in our batteries is to make sure each cell is contributing equally and they all work in unison. It ensures temperature of the pack doesn’t go too high, they don’t go below threshold voltage and prevent any kind of electrical leakage.

Here is a pic of BMS and battery cells from a Bosch powerpack.



So, BMS is the brain of battery pack.
 
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irenewg13

Active Member
Hi Irene,

Imagine a large group of ants carrying a heavy object. We gotta admire their coordination and skill to do such a thing. Each ant contributes in a positive way and together they are able to lift a weight that is almost 100 times their weight.

Similarly, the battery packs in our bikes have several individual cells that work in unison to give sufficient power to propel us.

Each cell can provide voltage between 3.0V(empty) to 4.2V (charged). You stack them up in different series/parallel configuration and you get 36V or 48V (most of our bikes are 36V).



But just like the amazing coordination of ants, the role of BMS (battery management system) in our batteries is to make sure each cell is contributing equally and they all work in unison. It ensures temperature of the pack doesn’t go too high, they don’t go below threshold voltage and prevent any kind of electrical leakage.

Here is a pic of BMS and battery cells from a Bosch powerpack.



So, BMS is the brain of battery pack.
Thanks, I hadn't seen the words, battery management system, in any info.