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Discussion Starter #1
Hi everybody,
Saying that I’m new to EV would be a total understatement. I’ll say for the record that I have very little clue what I’m talking about and don’t wish to offend with my utter ignorance!

But! I have been a petrol head for longer than I can remember, built and raced a number of high performance turbo ICE’s in a number of UK track championships. I have been looking into the possibility of EV performance vehicle for a while. I have read through a number of threads and builds on this fine forum and wondered if anybody can provide me with an answer to some questions.

1) Is there an electric motor that will provide me with an equivalent of 350hp/300ftlb of torque from a ICE? Either on its own or in series?
2) What would the power requirement for said motor be at?
3) If connected to a 5 speed manual clutched transmission how would it deal with things like shock loading or clutch kicking (IE: Raising the revs to a higher RPM than the relative wheel speed and “popping” the clutch to induce wheel spin)
4) How would it deal with ‘pumping’ of the throttle
5) What are EV motors like when being driven hard?
6) If said vehicle was an electric hybrid that used a small, efficient low hp engine to turn a generator. What sort of generator could i use and what power would it need to generate to run said engine?

Sorry for my first post basically being a load of questions, but i guess we all have to start somewhere!

Cheers

Chris
(from London)
 

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Hi Chris,

1) Is there an electric motor that will provide me with an equivalent of 350hp/300ftlb of torque from a ICE? Either on its own or in series?
Yes and yes.

2) What would the power requirement for said motor be at?
About 300 to 350 kW.

3) If connected to a 5 speed manual clutched transmission how would it deal with things like shock loading or clutch kicking (IE: Raising the revs to a higher RPM than the relative wheel speed and “popping” the clutch to induce wheel spin)
Electric motors work well with transmissions. No problem with shock. No need to slip or pop clutch. Just turn motor off, shift and turn it back on. From standstill, have clutch engaged and apply voltage to motor as fast as you want and you'll get all the torque pretty much instantly.

4) How would it deal with ‘pumping’ of the throttle
No problem.

5) What are EV motors like when being driven hard?
Great.

6) If said vehicle was an electric hybrid that used a small, efficient low hp engine to turn a generator. What sort of generator could i use and what power would it need to generate to run said engine?
Any generator you want. Depends on your hybrid strategy as to generator power.

I suggest you use the search engine on this board. Start out looking for _bi-moto_. A build thread by member CroDriver. It is a long thread, but will have all you points covered, except #6. Here it is for you: http://www.diyelectriccar.com/forums/showthread.php?t=28287&highlight=bi-moto

Hang around a bit and you'll find the answers.

major
 

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Comparing a DC series motor to a Gas engine V8, the DC motor can take far more abuse and can do More than the Petro engine you mentioned. The thing that will be limmiting is the Battery system, the controller can get expensive to depending on how fast YOU REALLY want to go. the motor is the most reliable and strogest link in this whole system. If you can dump your money in the batteries followed by the controller, you can go about as fast ahs you want.....
Yeah 300 HP is very "doable"...and 300 foot lbs??? Is even easier!!

look at the warp 11 High voltage version...and there are other out there too..
 

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...built and raced a number of high performance turbo ICE’s...
That's the point of reference I'm using for you. The first thing is you're going to have to do is flip a lot of your thinking a full 180-degrees to wrap your head around electric propulsion, coming directly from turbo ICE racing.

All the work that you had to do to get and keep your turbo ICE spooled up and in the powerband is out the window. I spent the first months on this forum trying to make my electric motor behave like an ICE, so I could adopt all my previous experience. Eventually, I realized that most of it was completely unnecessary.



...1) Is there an electric motor that will provide me with an equivalent of 350hp/300ftlb of torque from a ICE? Either on its own or in series?...
I think the ultimate choice right now for racing might be a Warp 11HV. In the thread Major linked you to, he pushed one to 500hp on the dyno. I currently have an 11-inch GE, but am seriously considering a Warp 11HV. 500hp in an electric motor is equivalnt to much more in an ICE because you have full torque from 0rpm - you can be deep into the powerband as soon as you put your foot on the accelerator. The other serious option is one of Jim Husted's siamese 9s, but his site seems to be down so I can't provide a link. It's http://www.jimerico.net/



...2) What would the power requirement for said motor be at?...
That brings up the most important, and most expensive, aspect of EV performance/racing - the battery pack. You need a high-power lithium battery pack if you're serious about performance and racing. Figure a minimum entry price of $15K, and more likely north of $25K. The horsepower is in the battery pack.



...3) If connected to a 5 speed manual clutched transmission how would it deal with things like shock loading or clutch kicking (IE: Raising the revs to a higher RPM than the relative wheel speed and “popping” the clutch to induce wheel spin)...
No need to rev it up and pop the clutch. As mentioned, you have full torque from 0rpm. Revving would actually be counter productive and pretty much a waste of time. Starting from 0rpm, just nail it and it'll pull like a raped ape (assuming you have the batteries to supply it) until redline, finish line, or fear come into play.

That also brings up another point. If you're racing, whether or not you even need a transmission depends on a lot of factors. The fastest drag racers have none - they're all direct drive (motor to differential). Again, you have to have enough battery though...



...4) How would it deal with ‘pumping’ of the throttle...
As Major said, no problem. Your drivetrain and tires must be up to the task of handling the torque hit each time though. Imagine repeatedly revving and dumping the clutch, or bumping the nitrous button.



...5) What are EV motors like when being driven hard?...
Like a properly built race engine - they pull hard and smooth. I've only felt a sample so far, but an 11-inch motor feels much like a large displacement V8. It plants you in the seat, and pulls relentlessly.



...6) If said vehicle was an electric hybrid that used a small, efficient low hp engine to turn a generator. What sort of generator could i use and what power would it need to generate to run said engine?...
I'm toying with this idea as well, but only as a temporary range extender. It must be removeable for racing because a generator setup that's powerful enough to accomplish the task is going to add too much weight to be beneficial in a racing environment. Again, a monster battery pack is most critical element. The White Zombie gets 100+ miles per charge, and is knocking on the door of a 9-second 1/4-mile pass. The key to EV performance is lightweight and powerful batteries.


Notice a theme here? ;)
 

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Discussion Starter #5
Fantastic info here folks!
Thanks very much for taking the time.

So the batteries are the key. :) I get it!

There are no electric cars racing in my scene so it would be a first.

Keeping in mind I know little about the workings of these sort of drive trains (or EV in general) am I right in assuming that it's the number and type of batteries that generate the required power to run that sort of engine?

Does anybody know of a generator that's capable of pumping out the required 300-350kw's? That's small enough to fit into a car?

Please go on the basis that I have a 67hp power plant that'll turn a geared 8,000rpm at full tilt and weighs about 70lbs. :)

Thanks :)
 

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Does anybody know of a generator that's capable of pumping out the required 300-350kw's? That's small enough to fit into a car?

Please go on the basis that I have a 67hp power plant that'll turn a geared 8,000rpm at full tilt and weighs about 70lbs. :)
67 hp = 50 kW. So 6 or 7 of those would do the job, if your generators were 100% efficient. At 80%, you'd need 8 or 9.

Going hybrid adds several degrees of complexity over and above a battery EV. And there is a large range of hybrid strategies to consider like series, parallel, combo, mild, range extending, sustaining, depletion, etc. Often times the fuel driven generator is sized to average power and the battery is used as a buffer supplying the peak power and for regeneration. But, at least in my opinion, hybrids border on relevance to this board.

My advice, build an EV first. Once you get the hang of it, you'll much better understand what a hybrid could bring to your table. And by the time you build your EV, there may be better batteries which kill your hybrid idea anyway.

In the mean time, read up on hybrids if you want. There should be plenty of literature out there. Probably not much here on this site though.

Regards,

major
 

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Yep, I agree with Major... Dump the hybrid idea - this would too complicated, too heavy and too expensive. A good battery pack would be lighter, quiet and even less expensive.

And it can even look really good





And don't think that building a 350 hp EV will be easy. Many show up and want to do it. I have seen just a couple that have really done it. I'm one of them. The other one is John Wayland.

But we're here to help you when ever we can... Good luck.
 

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I would also recommend reading Crodrivers thread, the final pictures are pretty but it's very valuable to read how he got there. Crodrivers thread was also one of the big influences on why I bought the Warp 11HV, and will be using Headway cells, 10ah instead of 8ah though, for a little more range but a little less power.

I think there will be more and more Warp 11HV powered vehicles on the road soon as people are able to complete their builds. I can't wait till mine is on the road!!
 

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I would also recommend reading Crodrivers thread, the final pictures are pretty but it's very valuable to read how he got there. Crodrivers thread was also one of the big influences on why I bought the Warp 11HV, and will be using Headway cells, 10ah instead of 8ah though, for a little more range but a little less power.
You do realize that I have a valid copyright according to US law on that design? :D
 

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Yep, I agree with Major... Dump the hybrid idea -
Good to hear from you again Cro. Cute little batteries you got in the trunk. Are those chrome plated under the Mylar? No wonder that sucker is fast :eek:

Hey, have you run any circuit races with beautiful green machine? Just wondering how the DC system holds up for longer than 400m. I am tempted to suggest the OP look at AC drives as I think he is not a drag guy.

And Tess has such a way with words, doesn't he :)

Kool :cool:

major
 

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Good to hear from you again Cro. Cute little batteries you got in the trunk. Are those chrome plated under the Mylar?
You never get bored making fun with me because of the chrome plated motor, don't you? :D

Hey, have you run any circuit races with beautiful green machine? Just wondering how the DC system holds up for longer than 400m. I am tempted to suggest the OP look at AC drives as I think he is not a drag guy.
I had some short drift races but no longer circuit races. Once I had to make 6 1/4 mile runs one after another and the motor made it without any problem. It heated up to about 75 C. But don't forget that my motor is not a stock Warp 11HV, we have no internal fan - we use a external blower instead of it because of our high-speed direct drive setup.



My DC-DC converter died recently and I had to go for a longer ride from my company to my home so I had to keep the fan off to have 12V juice for the controller. After 40 km the motor heated up to 110 C (sensor is located inside the stator) and the LED in my dashboard which was connected to the thermistor inside the motor lightened up. So it seems like a low power for a long period of time is worse than a very very high power for a short period of time. I believe that roughly the same battery energy was used for the 40 km of driving on regular streets and for the 6 quarter mile runs.

And Tess has such a way with words, doesn't he :)
Yeah, he's funny. I miss more of such guys on this forum, everyone is too polite and serious :rolleyes:
 

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I thought I'd jump in here and give you a heads-up on current LiFePO4 battery prices. I'm looking at a Warp 11HV with a Soliton 1 setup and am looking for a pack that can put out about 250 HP and have a 100+ mile range. I contacted Thundersky directly through alibaba.com and they gave me a quote for 72 of their 160 Ah cells. The price was $11520. That is an unheard of low price at $1 / Ah, and 15-day shipping via boat to the USA west coast is $450.

This is a 37 kWh pack, so it is capable of outputting 185KW (~250 HP theoretical) at 5C and 800 amps. And then for every-day use at 0.25 kWh per mile, it would give you a usable range of 118 miles at 80% DoD (Depth of Discharge).

Thundersky batteries are LFP (Large Format Prismatic) and are rated at 3C continuous and 5C pulse. If you want more power density then you should consider Cylindrical cells such as A123 or Headway. Headway, for instance is generally rated at 5C continuous and 10C pulse.

I had also contacted Headway through alibaba.com and they quoted me $1.30 / Ah for 780 of their 16Ah cells.
 

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It's really nice to see so many in-depth answers to the OP's questions. This is the most respectable forum I've ever been on. Can't wait to start a build!
 

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Disclaimer: I have no EV, but have read a lot. :D

1) Is there an electric motor that will provide me with an equivalent of 350hp/300ftlb of torque from a ICE? Either on its own or in series?
Yes, see above. One thing about electric propulaion is that it turns what we already know on its head. In an ICE, max power and torque only arrive way up in the rev range. With an electric motor, max torque is there from zero, and stays there until you pass several thousand RPMs. Max power is an almost direct line from zero to about where torque starts to drop. Electric motors are rated at continuous power, while ICEs are rated at max power. An electric motor can typically be overdriven to four or five times it's continuous rating in short bursts, so to reach 350hp/260kW, you might only need a 65kW motor. The short answer is that if you pit a hi-po EV aga8inst a hi-po ICE, the EV will win off the line, the ICE will only win after a long catch-up. Unless your circuits have straights of half a kilometre or more, you'll probably be first to the next corner.
3) If connected to a 5 speed manual clutched transmission how would it deal with things like shock loading or clutch kicking (IE: Raising the revs to a higher RPM than the relative wheel speed and “popping” the clutch to induce wheel spin)
You won't need to rev the motor, it'll break the tires loose all on its own. :)
A gearbox is a personal preference. Some like to keep it, so they can choose the most efficient gear for the job at hand. Some keep the 'box but lose the flywheel. Some get rid of it altogether. If you build a car like Wayland or CroDriver, you'll probably remove the 'box gear-by-gear. :lol:


I contacted Thundersky directly through alibaba.com and they gave me a quote for 72 of their 160 Ah cells. The price was $11520. That is an unheard of low price at $1 / Ah, and 15-day shipping via boat to the USA west coast is $450.
That's a fantastic price, but I still wouldn't touch TS for an everyday driver due to their well-documented quality and warranty issues. Maybe for a first pack for a racing/drag EV where you don't expect it to live very long anyway.
 

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I believe the quality issues are long behind them but 160AH cells are only rated at 3C (480A) continuous and you would need several in parallel to give the kind of amps needed for drag racing (unless you built a fairly high voltage pack.)
 

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That's the point of reference I'm using for you. The first thing is you're going to have to do is flip a lot of your thinking a full 180-degrees to wrap your head around electric propulsion, coming directly from turbo ICE racing.

All the work that you had to do to get and keep your turbo ICE spooled up and in the powerband is out the window. I spent the first months on this forum trying to make my electric motor behave like an ICE, so I could adopt all my previous experience. Eventually, I realized that most of it was completely unnecessary.




I think the ultimate choice right now for racing might be a Warp 11HV. In the thread Major linked you to, he pushed one to 500hp on the dyno. I currently have an 11-inch GE, but am seriously considering a Warp 11HV. 500hp in an electric motor is equivalnt to much more in an ICE because you have full torque from 0rpm - you can be deep into the powerband as soon as you put your foot on the accelerator. The other serious option is one of Jim Husted's siamese 9s, but his site seems to be down so I can't provide a link. It's http://www.jimerico.net/




That brings up the most important, and most expensive, aspect of EV performance/racing - the battery pack. You need a high-power lithium battery pack if you're serious about performance and racing. Figure a minimum entry price of $15K, and more likely north of $25K. The horsepower is in the battery pack.




No need to rev it up and pop the clutch. As mentioned, you have full torque from 0rpm. Revving would actually be counter productive and pretty much a waste of time. Starting from 0rpm, just nail it and it'll pull like a raped ape (assuming you have the batteries to supply it) until redline, finish line, or fear come into play.

That also brings up another point. If you're racing, whether or not you even need a transmission depends on a lot of factors. The fastest drag racers have none - they're all direct drive (motor to differential). Again, you have to have enough battery though...




As Major said, no problem. Your drivetrain and tires must be up to the task of handling the torque hit each time though. Imagine repeatedly revving and dumping the clutch, or bumping the nitrous button.




Like a properly built race engine - they pull hard and smooth. I've only felt a sample so far, but an 11-inch motor feels much like a large displacement V8. It plants you in the seat, and pulls relentlessly.




I'm toying with this idea as well, but only as a temporary range extender. It must be removeable for racing because a generator setup that's powerful enough to accomplish the task is going to add too much weight to be beneficial in a racing environment. Again, a monster battery pack is most critical element. The White Zombie gets 100+ miles per charge, and is knocking on the door of a 9-second 1/4-mile pass. The key to EV performance is lightweight and powerful batteries.


Notice a theme here? ;)
My question reflects on the #6 question but for a different application. http://www.cobraperformanceboats.com/page48/page48.html I would like to order one of these (when the money tree growing out in the back yard blooms) with out the factory engines and install a small diesel or gas motor to power a generator that would be good enough to power 2 of those Warp 11 motors for a total of 700hp at the props. @ 350hp ea. With your experience is that even close to being do able? Would I be using a lot less gas (which is the main point of the conversion) or would I be defeating the purpose do you think? I've been wondering about this for a few years now. I would have nightmares about the fuel bills for one of these things. Thanks.
 

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No free lunch. The LARGE generator would have to put out the HP you desire and you lose efficiency by using an ICE engine to power a generator and then power the 11's. The most fuel efficient answer is the factory engines. See the perpetual motion sticky for more info. (Not trying to be a smartass)
 

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If that boat was capable of going slow ( I believe they call it cruising ), you could have thought of sizing a generator slightly bigger in power output than your needed cruising power, and installing a battery pack large enough to cope with the going faster times. However, I cannot see anyone willing to go at any speed slower than FAST in that monster:D

Dawid
 
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Re: Very new to EV - Advice on 350hp equivalent motor & Genset

Hi All,

New to this forum as well but looks like some of you have done some heavy lifting.

Looking to convert (if feasible) a 350 HP Diesel to Electric with a Genset for Marine applications.

Has anyone done the research on the equivalent Electric KW motor to match the 350 Cummings diesel including weight differential?

Is there a Genset that could be used to power such an Electric drive?


Thanks in advance!
 
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