Complete newbie wants to go EV racing - will it end in tears?

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Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 20, 2017 12:47 pm

Hi Everybody, I've been pointed over here after looking on the Elmoto forum. I’m here because I’m seriously looking into the feasibility of building my first EV. I’m a competent mechanical engineer, I’ve built my own bikes from scratch, and I know enough to build a 12v wiring system, but I know absolutely zilch about electronics, and the last time I had anything electric powered was when I was building slot cars as a child. So I’ve spent the last few days going through as many relevant build threads as I can find, and trying to make sense of it all. I’ve sussed a few things out, but there’s loads of terminology I can’t even begin to understand – you guys are all pretty darn smart eh?

So here’s my thinking so far. I race flat track in the UK on ICE, but I’m massively inspired by the Alta Red Shift in flat track trim, and also what Preston Petty is doing with the Zero as a base. Both those bikes are way beyond my budget, plus at heart I’m a builder anyway, like I have been for my whole life. So I’m investigating whether I can possibly build it myself rather than ride a bought one.

I can put a rolling chassis together no problem, and I can fabricate and mount, but at the moment I’ve no real idea what I should be mounting. I need a set-up that will see me through a fairly precise fixed routine - six two-minute races (six laps of a quarter mile oval) in a day’s racing, plus a bit left over for restarts etc. I need around 30-35kw of peak power, and I’ll be running at around 45mph or so max, and I’d like the overall weight to be the right side of 250lbs, ideally around 220-230lbs. A good controller (with ‘feel’...?) is essential in terms of sensitivity to throttle response – I’ll be racing on loose dirt after all.

So far I've been looking at the Golden Motor 10kw, and the VEC500 controller to go with it. I'm thinking of running it at 48v, although I realise this will mean I need to draw more amps (around 280A?) to achieve peak power. Would I be better with a higher voltage to reduce the amperage requirements? It is essential to get good acceleration off the line. With an 18" rear wheel then 6:1 gearing would put me right in the max power at 3,400rpm at 45mph (if my calculations are good, it's many a long year since I did maths at school..), so I'd probably need a countershaft to avoid a huge discrepancy in sprocket size.

If anyone feels kind enough to help please, my initial questions are: Does anyone have any experience of that motor/controller combination? And what sort of battery system would I need to provide enough supply? I'm already aware of the dangers and risks of using Lipo, and although I know they are ideal for high discharge rather than duration, which is what I'm looking for, I don't feel confident enough to build my own system safely. Are there any alternatives that won't break the budget too much and not weigh me down with massive kgs?

I know I’m very much lacking in knowledge, and at 63 years old I’m not desperately keen to understand every little nitty gritty about flux reducers or all the other things I’ve no idea what they are. But I am keen if possible to put together a competitive EV race bike. So if there’s a combination of parts that work well together, and can be assembled and wired by someone who has a desire to make it work and isn’t afraid to ask about what he doesn’t know, I’d appreciate any help or advice please. Thanks in advance.
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Chalo » Dec 20, 2017 1:04 pm

I don't know anything about racing. But you don't have to be daunted by the electrical parts of your project. That part is relatively easy, compared to mechanical fabrication. You can do it.

Lithium polymer pouch packs are right for this application.

Lower voltage with higher current makes your wiring and connectors heavy and expensive. I'm curious what makes you want to use 48V rather than something higher. Getting your 35kW peak power on 48V will take about 1000A depending on system efficiency.

6:1 sprocket reduction is doable, if you can find the room for it. Don't put the sprockets too close together, because you'll need adequate wrap on the smaller one.
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by major » Dec 20, 2017 1:16 pm

Hi Shedster,

I don't have much time now, but want to caution you on the motor. Look for a better one. Hopefully some members can offer suggestions.

Good luck,

major

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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 20, 2017 1:28 pm

Hey, thank you for the swift reply. I just figured 48v was the least expensive option in terms of batteries?

I'm concerned about my lack of knowledge about charging, discharge, BMS etc, is Lithium Polymer not Lipo? What exactly is a pouch pack please? Are they the soft casing ones that I've seen damaged in various photographs so far...? Scary... I was hoping there'd be some of hard case batteries I could just add in series, along these lines:

http://www.electricmotorsport.com/ev-pa ... mnpo4.html

But I realise that 20ah isn't going to cut it. And if I go for 60ah (would that be enough anyway at 3C?), half a dozen of them to get to say 72v would rattle off over $2k (and I'm in the UK, so add at least 30% tax to that price).

Easy for you to say the electrical part is easy.... :lol: I can build a complete motorcycle from scrap steel, but then I've been doing that for over 50 years, all this electrical business is making my head spin... :shock:
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Chalo » Dec 20, 2017 2:40 pm

Yes, lipo = lithium polymer pouch cells. You have to bundle them together in a protective enclosure. The kind we're most familiar with comes from Hobby King and is jacketed only by shrink tubing. It's used predominantly in radio control model planes and cars. Depending on price and energy density, the packs are rated from 10C to 130C. The rule of thumb is to divide those numbers by four to figure out what you can actually get from them.

Hobby lipo packs don't come in nominal voltages over 36V, and the most cost-effective ones are in 4S and 6S packs (that's shorthand for number of cells in series). So you can place the packs in series to establish whatever voltage you want to work with, and in parallel to reach the capacity you need.
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 20, 2017 6:48 pm

Hi Chalo, thanks for the update. But to be honest, the more I see of Lipo batteries (being charged in the oven or fireproof cages for safety), the more I think I don't want to start building my own pack. I take your point about voltage, if I can find the right batteries (preferably lithium ion for safety?) I'd happily go to 72 or 96. But to run a 10kw motor, what capacity do I need then (I understand parallel and series connectivity to get more volts or more amps, just don't know how many amps I need to run the motor for say 15 - 20 minutes)?
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 20, 2017 7:18 pm

major wrote:
Dec 20, 2017 1:16 pm
Hi Shedster,

I don't have much time now, but want to caution you on the motor. Look for a better one. Hopefully some members can offer suggestions.

Good luck,

major
Hi, thanks for that Major. I'm aware the Golden motor isn't rated as the best on the market, but obviously the price appeals to me. Like anything, part of my difficulty is overall cost. I can by a brand new KTM E-Ride for £5,000 GBP, so it doesn't seem sensible to spend nearly as much as that to make my own, even if the idea does appeal to me a lot more.
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by major » Dec 20, 2017 9:02 pm

You might check out some of the packages offered here. http://www.thunderstruck-ev.com/motorcy ... kart-kits/ Or give them a call or message. I think you can do better for your money than Golden. Also consider used equipment. Maybe a wrecked emc (electric motorcycle). I've never seen a happy Golden user.

major

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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by mcdanyel » Dec 20, 2017 9:45 pm

I am well on down the road with my electric motorcycle conversion. I have de-iced and refurbished a '72 Honda CB450 Black Bomber as the donor bike. It is now time to buy the electric drive system and batteries.

I have also been looking at the 48v 10kw Golden Motors BLDC motor & controller + 18 used Nissan Leaf cells & BMS to make up the guts of the build. After researching Golden Motors a lot today, it seems like a risky gamble to buy any of their products. I am also looking at a Motenergy ME1003 + Alltrax SR 72400 controller instead of the cheaper Golden Motors option.

Does anyone have recommendations on a motor / controller combo?

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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Dauntless » Dec 20, 2017 9:51 pm

The nice thing about the complete kits at Electric Motorsport is they are complete. If you don't want their kit you know you do want the parts they list.

But you sound as though you want this:

http://www.electricmotorsport.com/ev-pa ... -650a.html
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by amberwolf » Dec 21, 2017 2:48 am

You might want to look at JonesCG's bike and racing threads (like his Voltron bike, etc).
this is a list of the threads he's started
https://endless-sphere.com/forums/searc ... =firstpost
if you want ot look thru those.

These are a couple of the racebike-specific threads
https://endless-sphere.com/forums/viewt ... 10&t=29916
https://endless-sphere.com/forums/viewt ... 10&t=12480
and a thread about why he went high voltage
https://endless-sphere.com/forums/viewt ... 30&t=45372


The one thing I can say is that it *will* end in tears...your wallet's, mostly. ;)

But possibly your own of joy once you get it all working. :)

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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by jonescg » Dec 21, 2017 4:03 am

Thanks for the recommendation AW!

Yes, pouch cells are nothing to be afraid of - just do it properly. Lots of horror stories are out there because people weren't doing it properly. Pouches are ideal for racing as they are typically awesome for power, but modest for energy density. High voltage is not the boogey man it's made out to be either, but again if done properly it works very well. Most commonly available motors and controllers work best on nominal voltages of over 300 V, and in my case, up to 700 V top of charge.

I've since moved on to screw terminations for them rather than soldering, and that's worked out really well. So if you have any specific queries, just ask!

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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by liveforphysics » Dec 21, 2017 4:05 am

If you have concerns about tears, racing likely isn't going to be your thing. It's approximately like shredding your wallet and joints and bones simultaneously, yet somehow turning out to be worth it all.

The golden won't satisfy you unless streaming smoke a few minutes into a race is your thing. A buying a used SR/DSR for it's drivetrain is likely the best long term Hp/$.
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 21, 2017 1:23 pm

Hi, thanks for the reply - the racing isn't new to me, I've been doing it for nearly 50 years! It's the EV part that has attracted my attention...

I'm listening to what people are saying about Golden, it seems that's not the smart way to go. I wish I could buy a used Zero, I could modify that just fine, but they aren't available in the UK, and new ones are a huge amount of money..... :roll:
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 21, 2017 1:33 pm

Thanks to everybody for all their input. I've spent countless hours searching through threads on here for the last couple of weeks, and looking up parts and prices, and I think the end conclusion is, I can't get what I want with the money I'm prepared to invest (and being outside the States only makes availability and prices even worse). I'm not generally one to give up on an idea, and if I was 20 years younger, or this was going to be my only race bike, it might be different. But I have race bikes already, this was only ever going to be an experiment. I'm intrigued by electric, I'd genuinely love to race one, but I can't justify more than about £4000 GBP (about $5k USD) for something that will have next to no resale value over here when I retire it.

Shame, but I have learnt a great deal about something I knew very little about, which is never a bad thing. I'm extremely impressed with what all you guys are up to, and the extensive knowledge you have, and the kindness you show in sharing it. I've not given up completely on the idea, if I ever come across a bunch of extra money, or a Zero at an affordable price, I'll be on it like a shot.

Till then, cheers y'all
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Duck-Stew » Dec 21, 2017 1:47 pm

44 hours worth of membership here and you've thrown in the towel?!?

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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 21, 2017 2:38 pm

I didn't say that did I? As I stated at the start, I came on here for specific advice and information, which I've received, with grateful thanks. It's a simple fact - I'm sure I could learn the technical stuff, but it's obvious I don't have anything like enough money to do what I want. I've been around enough to know what I can achieve and what I can't, and at this stage it simply isn't feasible for me with the budget I have. That's not to say I'm not still very interested, I'll be watching developments on here, still looking out for a good deal on used bikes/parts, and in the meantime hoping to win the lottery. I just didn't want people going out of their way to offer more advice when I can't afford to take it.
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Duck-Stew » Dec 21, 2017 2:52 pm

I didn't mean my comment to come off as negative. Sorry if it does.

There are less typical options which may warrant exploration. Have you tried the "used" parts section on this board? ElMoto's classifieds?

I have an Agni 95R which needs new brushes (which I have) and have yet to list if you (or the consortium of knowledge on this board) think that would be a viable motor to start with? I also have a stock Alltrax controller from the same '10 Zero S (again, if this is of interest...)

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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 21, 2017 3:34 pm

I understand, the written word can often cause problems that don't appear face to face....

Thanks for the kind offer (I think the 95R is a little short of power for what I want, plus being air-cooled I don't think it would take well to running in the gritty dust on track, although as ever I bow to greater knowledge than mine if someone offers it). I have been looking in the For Sale section. The biggest hurdle to that is being in the UK, not just the shipping costs but the taxes and import duty. If I get anything in from the EU, all I pay is shipping, but from the States I pay shipping, then a rate of import duty on the goods plus shipping, then a tax of 20% on the goods, shipping and duty combined! I was hoping there would be more stuff available over this side of the Atlantic, but it seems you guys are way, way ahead of anything we're doing over here. I'm sure that will change as time goes by and more people get interested. My plan for now is to keep doing a little research, grow my understanding, and look out for deals that might suit me, particularly from the EU.

As in many things in life, I tend to think if it's meant to be it's meant to be. I've done a bit of groundwork now, I have a better grasp of what I might need, time to just take stock and see what happens next perhaps...

Thanks again. ;-)
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Chalo » Dec 22, 2017 2:24 pm

Lynch motors are domestic production where you are. They're very expensive here, but in GB, maybe not prohibitive? Anyway, the Lynch 2X2 can do more or less what you want to do, and since it's a brushed DC motor, the controller can be relatively cheap and very simple to implement.

It's something else to look into, anyway.
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 22, 2017 5:28 pm

That's very interesting, thank you. I've just spent a happy hour wandering around their website, I think I'll be getting in touch with them in the New Year. Cheers ;-)
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Dauntless » Dec 22, 2017 6:25 pm

I don't want to act like you have no business changing your mind, but you can at least look at potential cheaper classes to try out. I would assume that there should be electric midibike racing for adults. That'll be 12-14' wheels, coming as a 50cc to 110cc. On my phone, real hard to find some online, but a new bike at $500 to $700 getting maybe a 7kw motor should be so pricey.
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by Shedster » Dec 23, 2017 4:11 am

Hi Dauntless, I get what you're saying, but actually there's no electric dirt bike classes at all in the UK, we are leagues behind what's happening over there, so I would be putting myself up against the hotshot 450 single ICE MX bikes. Which is the class I race in now on my vintage 1966 BSA (you can see I don't exactly follow the traditional path...) So the interest for me in EV is to be able to go out against them and be reasonably competitive - I'm approaching EV with a specific purpose from that unconventional angle rather than any desire to ride some sort of EV just for the sake of it. But the Lynch motors do look very interesting, I'm certainly not abandoning the idea yet... ;-)
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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by mcdanyel » Dec 23, 2017 10:59 am

Thanks Dauntless and Amberjack for the links!

I like complete motor packages as it saves time and keeps ordering simple on my end.

Thunderstruck Motors' "Budget Screamer" kit (http://www.thunderstruck-ev.com/budget- ... ushed.html) fits my build budget and looks to have almost everything I have been pieceing together with online research. Going to check some math to make sure it will push my old Honda frame to the speeds I want.

Electric Motorsports kits are twice the money but have complete liquid cooling systems built in already like in this kit (http://www.electricmotorsport.com/ev-pa ... -650a.html). I have been thinking that if I go the liquid cooling route that I would have to build my own using an existing from a used bike - not with this kit.

Now it just looks like a matter of balancing money/power/features for this bike.

Early on I seriously looked at buying a used Zero and just focusing on the design side of it. Zeros have great tech, but look just awful - like a plastic dirt bike. I soon found this rolling 72 Honda frame with a clear title on Criagslist and decided to go that route instead. Fingers crossed that this bike will not only look great, but have decent enough performance to be actually usable. If you guys haven't seen Nightshift's Leafy Savage build, then check it out for a build that doesn't just toss some lead acid batteries in a steel box strapped to an old frame (http://www.nightshiftbikes.com/savage/). Nightshift showed this bike off at the Handbuilt Motorcycle Show in Austin, Texas which inspired me to finally build my own EV.

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Re: Complete newbie wants to go EV racing - will it end in tears?

Post by alec » Dec 26, 2017 5:31 pm

amberwolf wrote:
Dec 21, 2017 2:48 am
one thing I can say is that it *will* end in tears...your wallet's, mostly. ;)

But possibly your own of joy once you get it all working. :)
Highly agree with this statement. My wallet sees four therapists after the Greyborg...
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