260v Dirt Bike 2021

cheapcookie · Mar 9, 2021

Hi guys, what does it take to go 260v on a dirt bike?

Motor choice???

Controller???

BMS???

Ktm did it, 260v 18kw 30A, anyone seen anything like it here? :?:

hugok · Mar 9, 2021

Everything gets more expensive, why would you want to go that direction?

High Voltage motor controller for example:
http://www.sevcon.com/products/high-voltage-controllers/

cheapcookie · Mar 9, 2021

hugok said:
Everything gets more expensive, why would you want to go that direction?

High Voltage motor controller for example:
http://www.sevcon.com/products/high-voltage-controllers/

The low current makes battery engineering much simpler in my eyes.

I've found high voltage cycles to be a different beast altogether since riding a zero srf. Worse than crack

jhoexp · Mar 9, 2021

cheapcookie said:
I've found high voltage cycles to be a different beast altogether since riding a zero srf. Worse than crack

Zero srf is not high voltage, just around 100V nominal (28S).

fechter · Mar 9, 2021

The BMS makes it a pain to use that high a voltage. 260v x 30A = 7.8kW, something is off with the math. The Alta had a HV pack something like that and if one cell goes weak, there goes the whole pack.

My Sur-ron is only 60v and pulls 180A (10.8kW). This is a lot easier to implement. 72v is probably a sweet spot for MOSFET based controllers. The selection of parts for 72v systems will be much better than for 260v.

cheapcookie · Mar 10, 2021

fechter said:
The BMS makes it a pain to use that high a voltage. 260v x 30A = 7.8kW, something is off with the math. The Alta had a HV pack something like that and if one cell goes weak, there goes the whole pack.

My Sur-ron is only 60v and pulls 180A (10.8kW). This is a lot easier to implement. 72v is probably a sweet spot for MOSFET based controllers. The selection of parts for 72v systems will be much better than for 260v.

A quarter the amperage for the same power. What is the weight of your surron fully charged?

cheapcookie · Mar 10, 2021

jhoexp said:
cheapcookie said:

I've found high voltage cycles to be a different beast altogether since riding a zero srf. Worse than crack

Click to expand...

Zero srf is not high voltage, just 100V (28S).

Dang that's crazy, I would have sworn it was high voltage. Can't believe it.

fechter · Mar 10, 2021

cheapcookie said:
A quarter the amperage for the same power. What is the weight of your surron fully charged?

Fully charged, it's around 125 lbs. Mine has double the stock battery. Top speed is around 50mph.

amberwolf · Mar 10, 2021

cheapcookie said:
Hi guys, what does it take to go 260v on a dirt bike?

The first question is, why specifically do you want to use that voltage?

Knowing exactly what you need to accomplish will help us help you find the stuff you need to do that.

Yermommy · Mar 10, 2021

cheapcookie said:
Hi guys, what does it take to go 260v on a dirt bike?

Motor choice???

Controller???

BMS???

Ktm did it, 260v 18kw 30A, anyone seen anything like it here?

260V is going to be hard to achieve without salvaging some EV car tech and trying to reprogram it. You would have to be very knowledgeable about physical hardware and software design. It would be easier to stay within <100v and parallel more cell groups for higher amps.

cheapcookie · Mar 10, 2021

I think the idea of using way less amps is pretty good. I don't know if I've made this clear but I want to recreate the ktm dirt bike. I'm not asking how expensive or hard it is? I'm just asking if there's readily available parts?

j bjork · Mar 10, 2021

An example of a controller:
https://www.emdrive-mobility.com/portfolio/emdrive-h300/

dforesi · Mar 17, 2021

cheapcookie said:
I think the idea of using way less amps is pretty good. I don't know if I've made this clear but I want to recreate the ktm dirt bike. I'm not asking how expensive or hard it is? I'm just asking if there's readily available parts?

I think most of us are just confused with the question. We understand what you want, just not why you want it. A high voltage bike isn't really going to feel different than a low voltage bike, at the end of the day it comes down to power (kW). Why are you trying to recreate the KTM bike, why not just buy one, it would be far cheaper.

The QS138 with gearbox has been shipping for a while now, that's certainly going to be the easiest way to create a home built bike. I agree with everyone else, if you want a high voltage solution you will need to buy used/salvage car parts. Even the Zero parts aren't truly high voltage.

dforesi · Mar 17, 2021

I guess I didn't answer your questions directly.

Are there parts readily available, no.

Are there parts available, yes.

kiwifiat · Mar 20, 2021

Buy a Gen3 Toyota Prius transmission for the princely sum of $75USD and remove the MG2 motor. Purchase a Chevy Volt inverter, prices start at $30 from US based Auto part dismantlers. The Volt inverter has 2 independent 111kW capable inverters in the case that are easy enough to separate but you would need to construct a new housing and IGBT cooling arrangement. Drop a Lebowski brain or an openinverter board into the Volt inverter and you have a cheap and powerful drive chain for next to nothing. The only question mark in my view is the battery, ~62S @4.2V is required for 260V, I would be inclined to run closer to 200V. I have a 48S pack at ~ 200V hot off the charger that would easily fit into a motorcycle.

Sounds like an interesting and fun project that is quite doable if you have the right skill set.

jhoexp · Mar 21, 2021

kiwifiat said:
Buy a Gen3 Toyota Prius transmission for the princely sum of $75USD and remove the MG2 motor. Purchase a Chevy Volt inverter, prices start at $30 from US based Auto part dismantlers.

They must be insanely popular there to have these prices! Prius here (Italy) were rare 10 years ago, and even more now. I could not really find anything at the dismantlers. You are probably better off buying a full used car from 2006/7 but they still sell them for 4000-4500 euro at least! And we have never seen a chevy volt/opel ampera (even if they seem to be imported), no one buys them here.

Can you point me to some used car parts seller that will ship overseas where I can find that stuff? I'd like to try...

kiwifiat · Mar 21, 2021

jhoexp said:
They must be insanely popular there to have these prices!

It is the other way around. A huge supply and small demand, the usual supply/demand curve situation. I think the 332 million population and car accidents has a lot to do with it.

jhoexp said:
Can you point me to some used car parts seller that will ship overseas where I can find that stuff? I'd like to try...

Try www.car-part.com . I don't have any recommendations but I can say that 18 years ago when I was building a megasquirt-1 for my 1968 Fiat 124AC I had no dificulty finding a USA based dismantler who was willing to ship me a fuel injection manifold off a 124 Spider and I was living in New Zealand at the time. Now I live in Canada and it is just a 40 minute drive down to Washington State for me to pickup parts but not currently due to Covid restrictions.

Europe seems very expensive, I'm lucky living close to the USA.

fechter · Mar 21, 2021

How about Fiat 500e parts? I used to see lots of those things around here but not so many lately. I suspect they all failed.

jhoexp · Mar 22, 2021

fechter said:
How about Fiat 500e parts? I used to see lots of those things around here but not so many lately. I suspect they all failed.

We don't have it here. That was a compliance car built in the US and sold only in California and Oregon. Fiat CEO Marchionne said he was loosing money (like 14000$) every car he made, and asked to NOT buy them. They did anyway and fiat sold about 5000 vehicles from 2013 to 2019. Last time I was in California, I was too surprised to see some of them around. I remember parking next to one charging at the Petersen Museum in LA.

Now we have a new 500 elettrica, built here in Torino (that I bet won't be sold in the US), but it has been available for just a few months...

jhoexp · Mar 22, 2021

kiwifiat said:
Europe seems very expensive, I'm lucky living close to the USA.

It's more complicated than that... I have been in the US many times in the last 15 years, but still amazed every time by the profound differences that I see. Sure the automotive market is a complete different animal for numbers, segment, prices, etc...

I'll see if I can get some cheap powertrain from the US. The UK seemed promising for that, but now with brexit is no more...

spinningmagnets · Mar 22, 2021

Alta made a really good dirt bike that reportedly could keep up with 450 gassers. I don't recall the exact voltage but I seem to remember it was somewhere around 300V?

You might check the Alta section of electricmotorcycleforum.com to see what components they used...

kiwifiat · Mar 22, 2021

If you proceed with this project, this site has some interesting information about using the primary traction motor from a Ford Fusion hybrid in a motorcycle:

https://nicjam.es/projects/ford_fusion_hybrid_motor/

They had a some issues because they opted not to use the OEM resolver for rotor position feedback but that issue is easily surmountable with a resolver to digital interface. The Fusion transaxles are more expensive than the Prius but the motor is more powerful. Re-housing the motor is going to take some pretty good mechanical skills but it looks doable to me. Another much less powerful (23kW) is the Hyundai HSG IPM motor that would be easy to mount in a motorcycle and has a water cooling jacket. I would guess you could probably burst 30kW for a short time without much problem.

Edit:

And this project: https://nicjam.es/projects/derpbike/ The author ended up at Alta Motors after graduating from MIT. The students at MIT seem to do a lot of very interesting EV related stuff.

thoroughbred · Mar 24, 2021

Is it possible to use the prius MG2 in its own case? I'm looking for a picture of it not bolted to the other motor as a complete assembly.

kiwifiat · Mar 24, 2021

thoroughbred said:
Is it possible to use the prius MG2 in its own case? I'm looking for a picture of it not bolted to the other motor as a complete assembly.

With a little bit of ingenuity yes. It makes a lot of sense to retain the original casing as far as possible, particularly the end that houses the resolver. I would just hack up the casing leaving nothing but MG2. You would need to make provision for cooling, the Prius has an oil pump that fills that role. If you are generating 50kW at say 92% efficiency you need to handle the 8% losses mostly in the form of heat. If you are making an EV dragster you don't really need to concern yourself about cooling since the duty cycle is so short.

cheapcookie · Mar 24, 2021

Thanks everybody for your answers. I guess It'd be good to answer the why 260v question now? Wouldn't there be less current draw? Longer range for the same amount of kwh?

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