0-60 Under Five Seconds

Joined
Jan 14, 2015
Messages
18
Location
Michigan
Hi, I have been lurking on the forums for a couple of weeks now and I think I'm ready for my first post! I want to build a street legal moped electric trike capable of 0-60 in under 5 seconds, I say street legal but really all I want to do is have it pass inspection at the Secretary of State office :lol: (1500 watt stickers are easy enough to purchase). I want to use HK lipos and build some kind of aluminum frame, but what I am really worried about currently, is the motors and controllers. I really don't want to spend thousands on this build, but I also really want to kick some mustang butt! So I guess my question is, is their any powerful yet inexpensive motors/controllers? I was thinking maybe a front wheel drive 9c hub motor set up that hopefully can get 16kw+? This is probably a really really bad idea but the whole electric idea just sounds so awesome! Thanks a ton for reading my first post!!!
Will
 
JohninCRs hubmonster will get you there easily.
 
60mph? with a front wheel drive 9c? Reaching 60 km/h in 5 seconds is probably not achievable with that combo, let alone mph.

I hope it doesn't come across as dismissive, but you definitely need to do quite a bit more reading and math. You're going to need substantially more motor than a 9c, definitely no front wheel drive and certainly will need to spend many thousands to achieve your goal. It's not impossible, but it is definitely difficult and definitely expensive. 5 seconds to 60 on the street is the domain of the Zero S or the Brammo Empulse R. You can achieve the same result with less power and less weight, but it's still not fwd9c levels of easy.

What are your other requirements? Range/purpose/expected usage pattern?
 
I'm afraid your going to shell out some cash for that acceleration and speed I don't think 500.00 or a 1000.00 or even 1500. will cut it. Maybe it's just me overpaying for that kind of performance. If you put 16 Kw in the front a torque arm might be necessary, but I'm not sure.
 
I would be pretty surprised if you could build something that would hang together long term and be nice to ride for less than $4k all in. I would love to be proven wrong :)

If I was to attempt this I would go with LFP's suggestion, John in CR's motors are pretty unbeatable for bang vs buck. Hub monster, 13" rim with wide tire. Frame could be a number of things, but wheel base would have to be dramatically longer than your average bicycle to get a decent amount of thrust.

Power wise, back of the napkin calculations spit out something like 22-25kw input power with a system weight of ~70kg, light-ish rider. That requires something like 1.5kwh of >40c lipo or 20s 20ah roughly.
 
Sorry I was not a little more clear with what I am planing, but I'm planning on building a small aerodynamic-ish trike with a range of maybe 10-15 miles used when the weather is nice to use to go to school, otherwise it's the bus :-(. So from what you are saying a duel (or maybe triple) 9c oil cooled set-up is not worth pursuing? 20ah of 40c lipo would be about thousand which is little more than expected but doable, what if I used low C lipo for cruising then bring in the lead acid to go fast 8) ? (I hope I'm not sounding like a total cheap skate but like any student money's tight) thanks for all answers I'm a total noob for all this so any comments are well appreciated.
 
One hubmonster > 3 oil filled 9C's.
 
Willjones017 said:
Sorry I was not a little more clear with what I am planing, but I'm planning on building a small aerodynamic-ish trike with a range of maybe 10-15 miles used when the weather is nice to use to go to school, otherwise it's the bus :-(. So from what you are saying a duel (or maybe triple) 9c oil cooled set-up is not worth pursuing? 20ah of 40c lipo would be about thousand which is little more than expected but doable, what if I used low C lipo for cruising then bring in the lead acid to go fast 8) ? (I hope I'm not sounding like a total cheap skate but like any student money's tight) thanks for all answers I'm a total noob for all this so any comments are well appreciated.

LFP said it best, you're better off with one high quality motor than several disposable ones. With a small motor at some point you reach saturation point where more power in doesn't result in more power out, only heat. Your requirements are well beyond this point of diminishing returns for almost all 'bicycle' type hub motors. Hub monster is a different beast and the limits still really haven't been pushed, certainly not to the point of saturation.

Lead acid has no place on a high performance electric vehicle, or in fact any electric vehicle at this point. Big factor in acceleration performance is total system weight, lead acid is going to throw that in the bin pretty quickly. Your train of thought regarding two types of batteries is a good one, you can potentially run two varieties of lipo in parallel to cover your power peaks while delivering the required range for less $$ than a homogeneous pack, but it's more complexity and makes it a little harder to predict exactly what load each battery will see.

Regarding controllers - you're perhaps going to struggle with building something that will reliably deliver 24kw input for not a lot of money, cheap trapezoid 'infineon' type controllers at ~12kw each are a little bit hand grenade. You can luck out and find a combo that works for an extended period of time but it might take you a few tries to get there... personally I would be purchasing 2x Sabvoton sine wave 72v 150a controllers as seen here

These should deliver 150a battery @ ~80v (12kw) pretty reliably based on other experiences on these boards. They also have proper throttle control which with this level of power is pretty essential. They have proper phase current control which will allow for programmable torque at low speeds without being massively excessive like with the 'dumber' controllers (which leads to failures). They have some field weakening/timing advance functionality that allows you to increase top speed beyond the standard KV of the motor, allowing you to push through to target speed despite having a very small rolling diameter wheel.

You will need some fabrication experience or access to somebody who can fabricate to come up with a frame that can accommodate the hubmonster in rear wheel, the substantial amount of battery somewhere it won't be impacted if you bail and correct geometry to handle and stop safely. You will need to think about charging and allow for that in the total budget. If you're planning on reaching 60mph you need to be able to stop reliably, so decent brakes.

I really hope you build this, I have been thinking about it for quite a while myself - but I do have to ask.. do you really need ~20+kw/60mph to get to school? I commute 11 miles each way every day with <5kw, i'm beating all traffic off the line and up to 35 mph cruise - I usually don't see a car more than once as I pass at the next light. My *average* speed over the journey is only a bit less than the speed limit, so there's no way I could go any quicker without blatant and excessive speeding. My bike was built to take 12kw input reliably, however in practice I just don't need it.
 
100volts+ said:
lead acid to go fast

On the ES forum using the words "lead acid" and fast in the same sentence is heresy.


:lol:

I would better say "lead acid" and acceleration in the same sentence is heresy

Doc
 
Welcome on the forum Will.

Your project is feasible, but i would suggest to start by the begining first.

First get expreience on a moderate power ebike project , learn what to do and not do, spend hours reading from experience of the E-S comunity and this will give you more chances to succed and also save money!

And dont forget aerodynamic!!! :wink: this will save you alot of power requirement and over weight ! past 50km/h the wind begin to be strong and limit your acceleration. back in 2009 when i did 94km/h with a simple X5 and 18 fet infineon the bike was consuming 14.5kW and after i added fairing and a bubble windshield it only consumed 7.9kW... With that extra availlable power my speed problem to 94.3kmh and not the 117kmh i have calculated was not the power but that &?**&?%&*%? speed limit i forget to be set to 75% on teh infineon during the speed record!! lol so i learned that patience and concentration and focus are also really important when you want to do epic things lol!

Also there is alot of great tools to simulate the accelerations like the ebike simulator from ebikes.ca and also the SWbluto simulator using java. It is very accurate! Dont foeget... Simulation cost way less than tests on the track! then once simulation are correlated with real life performances you are on the right track sir! then you can begin tuning and fun intensify once again!

What are your actual personnal experience on a 100km/h electric bicycle?

Good luck for your project

Would be great to see your ebike racing and winning against a TESLA S like Luke did! but to acheive that he needed a 40kW Zero motor and 660A phase 116V controller :lol:

Doc
 
Wow! Thank all of you guys for your all of your incredible respondes! I listened to what all of you have had to say and have realized that I am going to get a little more familiar with the e bike world before I build something capable of beating a Tesla! I think my best course of action is to be little more realistic with my goals :| Instead of building a 0-60 killer, maybe I build the frame for the hub monster start working on my collection of Lipos and instead use 1 of the two controllers that was recommended to used with a hub monster and everyone's favorite a 9c (or something simaler). That way I don't kill my self, and once I'm ready and I can feel safe upgrading to killer power, I won't throw away tons of money towards parts that will be useless, and it will be a very valuable learning experience. What do you guys think am I better off going big at first or keeping it simple and gradually learning? Thanks tons for all this interest!
Will
 
You're absolutely better off starting off small and gaining experience before you go big. There's a lot of ground to cover to learn all of the facets of building a functional bike, then a bunch more to build one that's mind-bendingly quick. There's a ton of stuff I don't fully understand and a lot more I couldn't even define. I still hope you build something sportbike quick, though you definitely won't need it to get to school in a hurry :)
 
Where is a good place to buy a 9c 3004 hubmotor on ebikes.ca they were around 300$! I was led to believe they were closer to a 100$ but 300$ is just insane!!! Also on a side note where is a good place to purchase a Hubmonster?
 
Willjones017 said:
I want to build a street legal moped electric trike capable of 0-60 in under 5 seconds, [...] I was thinking maybe a front wheel drive 9c hub motor set up that hopefully can get 16kw+?

Front drive will not get you to that level of acceleration. The rear weight shift under strong acceleration doesn't allow enough traction on the front wheel for that. You won't even find any front wheel drive cars that can do it, and they have a much less challenging weight distribution problem than any bike.

EDIT:

On reflection, I think you mean using a front hub motor (narrow, no chain drive, symmetrical spacing) in the rear of the bike. Is that right?

Either way, I think it's not a good idea to put that kind of torque through a system that uses only a flatted threaded axle to constrain it.
 
Hub monster will get you there pretty easy, i would do a trike with a single rear wheel and then use a hub monster as it comes with the lowest profile tire on it you can find.
All up cost for the hub monster will be ~800USD or so with the rim and tire depending on delivery. Some minor machining to the hub monsters shell to allow better cooling and it will be a mustang killer.

Then a pair of Sabvotons to run on 20S(84V max) will be around the 700usd mark, some simple modification to the Sabvotons will increase the power output which is very very beneficial to you and the total package will net you around 30kw.

Yes i have used all these parts, mine is all on a 150kg full road registered motorbike so pushing a sub 30kg trike around with you hanging on will be awesome. 9C motors will not cut it, even a pair of cromotors would struggle against a single hub monster.
 
Sorry I was not a little more clear the 9c will just be used to build the frame and learn more about e vehicles then I will hopefully upgrade to the Hubmonster curious is there any more cost effective options than the hub monster?
 
Power to weight plus proper gearing is everything for a low 0-60 time. How much do you weigh?

It's sound like you're on a fairly tight budget, so it makes no sense to me to first buy junk and blow 2/3rds of your budget on something you definitely won't be satisfied with. I you have metal working capability and accept advice from the few who have done pretty extreme acceleration the easy way and on a tight budget, then I can pretty much guarantee success. If you want to go off on your own learning from your own mistake, and are starting with near 0 knowledge of electric drive systems, then maybe you do want to start slow.

Used stuff is the best way to stretch a small budget, and the best route for that is to start looking for a non-working high power electric scooter to pick up cheap and scavenge major parts like the motor.
 
You also have to consider that if the primary build criteria is a best 0-60 time, then you need a max speed of 80-90 or more. Acceleration drops off rapidly above peak power, and when your system is tuned for maximum acceleration, then peak power occurs at 50-60% of top speed. With an oversized motor current limiting can extend the peak power point significantly higher as a % of top speed, because the motor is capable of producing more torque at low speeds than can be put to the ground without flipping over.
 
From everything that has been said I just don't thing that my goal of a trike capable of 0-60 in under 5 seconds is a realistic goal money is tight and I don't know if I could justifying spending that much on project, but I am still in love with electric and was curious if there is any inexpensive yet really fast design that could be copied from someone or built?
 
Well I defintly think fast is the coolest option what kind of money would it take to go 50mph maybe a beach cruiser throw the pedals away and put a big motor in with x2 6s hobby king multistars 10ah?
 
Fast may look cooler to others, but acceleration is more fun on the bike. My bicycle based ebike will exceed 100mph, and is scary quick too, but I'd be hesitant to ride a beach cruiser that exceeded 30mph. For a hardtail at high speed, you want long and low. I love my cargo bike in that regard, and it tops out at 60, but you better be paying attention because a pothole or significant bump at significant speed gets interesting in ways I choose to avoid. Of course paying attention every second you're on an ebike is highly recommended.
 
Willjones017 said:
Well I defintly think fast is the coolest option what kind of money would it take to go 50mph maybe a beach cruiser throw the pedals away and put a big motor in with x2 6s hobby king multistars 10ah?

Before you buy stuff to go 50mph on a beach cruiser, I suggest you find a really long, really steep hill (about 20% grade, very uncommon) and try to experience what 50mph feels like on a beach cruiser. I sort of doubt you'll want to do that very much. I don't think you'd even enjoy 40mph on a beach cruiser, and that's a lot less energy. Have plenty of room to run out, because a beach cruiser will not stop from that speed in any reasonable distance.

You would need high current batteries like Nanotechs, not high energy, low current batteries like Multistars (unless you plan on having a whole lot of battery). You'll need almost 6kW to the wheel, so reckon 8-10kW from the battery. It won't be a cheap system that can do it without burning something up.
 
Before you buy stuff to go 50mph on a beach cruiser, I suggest you find a really long, really steep hill (about 20% grade, very uncommon) and try to experience what 50mph feels like on a beach cruiser. I sort of doubt you'll want to do that very much. I don't think you'd even enjoy 40mph on a beach cruiser, and that's a lot less energy. Have plenty of room to run out, because a beach cruiser will not stop from that speed in any reasonable distance.

You would need high current batteries like Nanotechs, not high energy, low current batteries like Multistars (unless you plan on having a whole lot of battery). You'll need almost 6kW to the wheel, so reckon 8-10kW from the battery. It won't be a cheap system that can do it without burning something up.

+1 Chalo
 
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