45KW + Electric Dirt Bike Best Motor, Batteries, Controller

Benventador

10 µW
Joined
Mar 8, 2018
Messages
6
Hi
I'm new to this forum and keen to learn.
I am going to build an electric dirt bike using a KTM rolling chassis but I have very little knowledge of the motor, batteries and controller I need to use.
So what would be a good motor that is fairly light, reliable and 55HP plus?
What are the best batteries for weight and around 1.5-2 hours hard riding?
What is the best speed controller?
What else do I need to know about such as charging etc?
 
https://endless-sphere.com/forums/viewtopic.php?f=12&t=90808&sid=5e67db82f6a57743b5b662175df73b94

Yeah, people always trying to discourage, eh? So read up that one, rather the similar project. On the road at the moment, maybe I can find a few things when I get home if you go on posting your plans.
 
Hi thanks for your reply.
My goal is to build a bike that is similar to the Alta Motors redshift MX.
The bike is not available in Australia yet and I believe it's $12000 USD. So I was thinking if I can get a lightweight motor and battery pack I can build something as powerful for a little less. I have the equipment to mount the motor and batteries etc. I just need to figure out the set up. I've done a little research and I definitely think it would have to be a water cooled motor for motocross.
 
I found this on YouTube he's got 60HP out of it but it's a custom zero motor. I could do with something that will fit straight off the shelf.
https://youtu.be/jzPgDbhrHVE
 
Perhaps 45kw would be a little excessive. I didn't realize these motors produce so much torque. A modern 250 motocross bike produces 45HP and 20LB of torque and a 450 58HP 35LB.
So I'm thinking the best option for weight would be a smaller motor with more power from the batteries and an large cooling system?
I'm also thinking lithium ion batteries would be better as they are not as fragile. So what are the best batteries to go for?
 
Where are you based Ben? (Assuming your name is Ben)

I helped Sketch with his bike (supplied the battery) and he's sourced some good parts from around the place, including a 40 kW peak motor; an M-force or something similarly named.

$12k will get you a pretty fun bike, and probably about 80 km range around town without going too overboard with battery capacity.

I use pouch cells for the power, although there are some impressive pouches offering over 200 Wh/kg and still 3C/5C discharge performance. Lots of options at least.
 
Thanks for the reply. I'm based in Tingalpa, it's about 20ks south of Brisbane.
Would pouch cell be strong enough? I want to use the bike for motocross. I did a little research and I think for the battery I would be best off using 18650 cells like the Tesla cars. I'm assuming the Alta bike also uses 18650 cells in series and parallel, it's running 350v and 16571mah. Would I be right in thinking that is 5 x parallel and 100 x series?
What motor and controller can you get me?
After a little research on the Alta bike I see it's running a 42 ft lb motor which is geared to produce 147ft lb and 50 hp.
So if I could run 350v what kind of motor would I need to get 50+ HP and 150+ ft lb of torque?
 
Choose the motor and inverter first, then design the battery to suit. If you can find a motor and drive capable of delivering all the torque and speed you need at say, 120 V max, then build a battery to suit. If that happens to be 350 V nominal, then build that. The Alta bike is 96 in series, and at least 5 in parallel. Not sure which cell they use, but it's probably at least 3000 mAh under a 1 C discharge. That equates to a bit over 5 kW which is what you would be doing most of the time (cruising at 60-70 km/h).

And that battery will need to be optimised for range, power and space/weight constraints. Cylindrical cells tend to have higher energy density, but the power density is not that flash. If you need power (like, hundreds of amps) then pouch cells might be the best option. Horses for courses. I use 30 C continuous cells in Voltron, but it's only 2p (10 Ah) at 630 V. We can easily fit 12 kWh or more, but the weight starts to get unwieldy. Any battery pack will need to be inside a tough, rigid, waterproof enclosure where the cells are effectively potted, otherwise the vibrations will kill it.

This motor would fit the bill nicely - but at $10k delivered it blows the budget.
http://www.phi-power.com/wp-content/uploads/2017/04/Phi271-Specsheet-V1.3.pdf

Otherwise go for a liquid cooled Motenergy ME1304 http://www.motenergy.com/mepmwacomo.html and opt for a lower voltage / higher capacity battery. They make some bigger ones too, with winding options to suit.
 
I would get a Kuberg Freeride or a Sur Ron and ride them to get an idea of the limitations of electric for motocross. They will cost you the same as what you would put into the build and you would get to ride more and learn about - 48v vs 60v - the role of the controller - direct drive vs mid drive belt, etc, etc.
 
Benventador said:
Hi
I'm new to this forum and keen to learn.
I am going to build an electric dirt bike using a KTM rolling chassis but I have very little knowledge of the motor, batteries and controller I need to use.
So what would be a good motor that is fairly light, reliable and 55HP plus?
What are the best batteries for weight and around 1.5-2 hours hard riding?
What is the best speed controller?
What else do I need to know about such as charging etc?

did you hear about harley davidson motorcycles recent investment and now shareholder in Alta motors?? so Alta motorcycles will likely be available at Harley dealerships soon to take advantage of this new partnership.. maybe by the time your build is finished you could just walk into your nearest Harley dealer and buy an Alta motorcycle instead.. also, it would likely be difficult to cram very much battery capacity / range / duration into a frame designed for petrol with their limited space available.. even the Alta with a pretty large and therefore heavy battery has very limited range / duration compared with a petrol bike.. when you say that you want a bike for motocross do you mean at the track or woods riding?? in addition to the ktm electric, Sur-ron, and kuberg, you may also want to have a look at electric motion motorcycles.. EM is available in trials and enduro models and they have dealers in Australia for test ride, etc.. if you have facebook you may be interested in this electric motorcycle discussion / build group : https://www.facebook.com/groups/electricmotorcyclebuilds/

and parts sales / exchange : https://www.facebook.com/groups/669208779870993/
 
Similar project, sort of. His is turned into a supermoto. But he could have kept it mx style. Make sure you watch the video #2 and #3 by the same poster. As you can see more details of what it takes to get a reliable build in the 50 HP +.

https://www.youtube.com/watch?v=TyHj3yViHGY
 
Thanks for all the replies.

Jonescg I think I saw the voltron in a YouTube video, has it got 2 motors? Looks pretty cool. I'll come and watch you if you're at Queensland raceway again.
I'm thinking maybe I could go with 5 battery packs that can easily be removed from the bike if more than 2 hours riding is needed the batteries can be swapped out while the others charge. Plus 5 batteries could help with weight distribution. But if you think pouch batteries could take the abuse I'm open to suggestion.
I was looking at your bike and wondering if 2 smaller lightweight motors could be an option for motocross?

The advantage of a ktm is it's a steel frame so it's easier to mess around with and I'm convinced the flex of a steel frame is better for motocross.

The Alta bike is a proper motocross bike it's recently won Bercy supercross and came 3rd in Red Bull straight rhythm. Both events are world class events. Motocross is really the ideal sport for electric bikes to break in to. The price for an Alta is $15000 AUD. I'm thinking if I can build a bike with the same or more power and a lighter motor + battery + controller set up I'd build more than one bike and start selling them.
A bike built in Australia could really sell well in Australia so if anyone wants to get involved that would be great. I'm looking for solutions though not problems 😂
 
Benventador said:
Thanks for all the replies.

Jonescg I think I saw the voltron in a YouTube video, has it got 2 motors? Looks pretty cool. I'll come and watch you if you're at Queensland raceway again.

Voltron only has one motor - an Evo AFM140-4. You might be thinking of Ripperton's dual motor machine?


Benventador said:
I'm thinking maybe I could go with 5 battery packs that can easily be removed from the bike if more than 2 hours riding is needed the batteries can be swapped out while the others charge. Plus 5 batteries could help with weight distribution. But if you think pouch batteries could take the abuse I'm open to suggestion.
I was looking at your bike and wondering if 2 smaller lightweight motors could be an option for motocross?

You can easily go for a 2.6 to 3 kWh battery which can be swapped out between races. Simply have three in use. One cooling down, one on charge and the other in the bike.

Benventador said:
...
A bike built in Australia could really sell well in Australia so if anyone wants to get involved that would be great. I'm looking for solutions though not problems 😂

Yeah, there are single dealerships in the USA who sell more bikes in a year than the whole of Australia. It's a tough gig...
 
jonescg said:
Benventador said:
I'm thinking maybe I could go with 5 battery packs that can easily be removed from the bike if more than 2 hours riding is needed the batteries can be swapped out while the others charge. Plus 5 batteries could help with weight distribution. But if you think pouch batteries could take the abuse I'm open to suggestion.
I was looking at your bike and wondering if 2 smaller lightweight motors could be an option for motocross?

You can easily go for a 2.6 to 3 kWh battery which can be swapped out between races. Simply have three in use. One cooling down, one on charge and the other in the bike.

Benventador said:
...
A bike built in Australia could really sell well in Australia so if anyone wants to get involved that would be great. I'm looking for solutions though not problems 😂

Yeah, there are single dealerships in the USA who sell more bikes in a year than the whole of Australia. It's a tough gig...

maybe talk to the guys at Braaap .. they have a 60volt electric pitbike with electronics provided by Catavolt AU.. and they did a prototype full size electric motocross bike..
[youtube]6v-LPM4p9TY[/youtube]

there is also Denzel, based in Australia with manufacturing in Asia..
[youtube]WSc4pBom7LI[/youtube]
 
Looks like the Alta is a capable bike to say the least! I'm impressed.[youtube]CTmuawNFp8Q[/youtube]
 
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