What would you do with 4000W power?

pushkar

Well-Known Member
I did bring up 21700 packs in our earlier discussions on the battery for the superbike. There was no response. So, I had just assumed that it wasn't a viable option for us.
Sorry if I missed that. Right now there is no advantage of 21700 packs. Ad the molds become available, we can switch over. The superbike piggy pack can pretty much be any pack.. so as battery prices decrease and 21700 becomes more prevalant, we can switch.
 

onlineaddy

Well-Known Member
So it’s ok for the integrated battery and the external pack to have different formats/chemistries and still work alongside one another?
 

pushkar

Well-Known Member
Well, if such bikes from the original post catch on, I think I'd dedicate some work to a purpose-built trailer, so one could carry the necessary batteries to be able to go more than 10 miles. ;)
Like Carla Cargo.
 

dblhelix

Well-Known Member
I have seen carla cargo in NYC more than once. It is insane how well that works. Apparently Tern isthe US distributor for the trailers.


That being said, I dont know which is good for cargo - mid drive or something else. See https://www.radpowerbikes.com/pages/commercial-radburro .... they are a central engine, a proven hauler style design. However, with something like Carla Cargo, there is a lot of other regular bike options.
I saw one set up with a Giant Quick-E, which surprised me. I didn’t see it in action, so I don’t know if it was an ez haul or not.
 

Johnny

Well-Known Member
I was wondering how will rohloff hold under 4000watts ?

It is nice to see the capabilities of Bafang ultra with the new controller though, I am impressed that it can sustain almost 10 times the output of mainstream mid drives like bosch. How is the efficiency over 3000watts?
 

pushkar

Well-Known Member
I was wondering how will rohloff hold under 4000watts ?

It is nice to see the capabilities of Bafang ultra with the new controller though, I am impressed that it can sustain almost 10 times the output of mainstream mid drives like bosch. How is the efficiency over 3000watts?
In the 3000W range, there is nothing to benchmark efficiency against.


Rohloff, or any other gear hub, will NOT handle 4000W. It will be a chain + cassette only. Or a custom belt (think motorcycle).
 

smorgasbord

Well-Known Member
Right now there is no advantage of 21700 packs.
If you watch the power tool space, it seems that the technology to switch over from 18650 to 21700 is proven and already widely available. See this video:

Just needs to come down from power tools to eBikes.
 

pushkar

Well-Known Member
If you watch the power tool space, it seems that the technology to switch over from 18650 to 21700 is proven and already widely available. See this video:

Just needs to come down from power tools to eBikes.
Yeah.. I should not have said "no advantage for 21700 cells". What i meant to say is that right now as it stands, there aren't widely available 21700 molds with the capacity we need. We can make a custom mold but that is a lot of$$ and it will be a custom design. Sorry for the confusion.
 

Asher

Well-Known Member
I think it's doing a disservice to ebikes to talk about power in terms of maximizing speed, instead of *maintaining* *safe* speeds. With 50 lbs of cargo and a 200 lb rider, 5 hp would let you maintain class 3 speeds uphill. That's why the class 3 spec in EU allows that power. The American regulation was written by an industry that wants to sell profitable toys, and the euro cycling advocates want to give people tools, specifically car and moped replacements.

It's also bad form to speak in terms of watts to make e-bikes sound more powerful and threatening then they are, which empowers the e-bike critics. Horsepower is what we use for road vehicles. 4000w is 5.3 hp.
 

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pennybags

Member
I think it's doing a disservice to ebikes to talk about power in terms of maximizing speed, instead of *maintaining* *safe* speeds. With 50 lbs of cargo and a 200 lb rider, 5 hp would let you maintain class 3 speeds uphill. That's why the class 3 spec in EU allows that power. The American regulation was written by an industry that wants to sell profitable toys, and the euro cycling advocates want to give people tools, specifically car and moped replacements.

It's also bad form to speak in terms of watts to make e-bikes sound more powerful and threatening then they are, which empowers the e-bike critics. Horsepower is what we use for road vehicles. 4000w is 5.3 hp.

Where did you derive "speed" from this discussion ? The speed is what the speed is... it is primarily a function of the gearing. You can ride a regular bicycle at 30MPH at the right gearing.

Why is it bad form to talk about power ? People worldwide use metric, US uses imperial. Watts / HP ... It is what it is.
 

smorgasbord

Well-Known Member
Yeah.. I should not have said "no advantage for 21700 cells". What i meant to say is that right now as it stands, there aren't widely available 21700 molds with the capacity we need. We can make a custom mold but that is a lot of$$ and it will be a custom design. Sorry for the confusion.
Hey Pushkar, you said "packs," which is absolutely the right thing to say - my post wasn't meant as contradictory to yours, but supportive.

And as well to indicate that I do think eBikes will be going to 21700's relatively soon.
 

Asher

Well-Known Member
Why is it bad form to talk about power ? People worldwide use metric, US uses imperial. Watts / HP ... It is what it is.
Lol ok totally misrepresented and misunderstood what I wrote. The whole world uses horsepower for licensed road vehicles. Imperial hp = 746 w, metric = 736 watts.
 

smorgasbord

Well-Known Member
Curious, why do you think so? They've been around for a couple years now and no one but Luna seems to use them.
Did you watch the video link I posted? Higher energy densities mean smaller packs for same power, or more power in same size packs. Hand power tool companies could just have used more 18650s, but decided to switch to 21700s as their packs increased in capacity. Same will be true for eBikes.
 

byunbee

Well-Known Member
Did you watch the video link I posted? Higher energy densities mean smaller packs for same power, or more power in same size packs. Hand power tool companies could just have used more 18650s, but decided to switch to 21700s as their packs increased in capacity. Same will be true for eBikes.
Thanks for clarifying. I was working and just glanced at the posts in between.