# Useable power



## Nathan219 (May 18, 2010)

Has anyone built a vehicle that can actually use 1.2Mw or 1600hp the Shiva can produce? I usually use between 30-40kw to accelerate my Leaf up to speed. When choosing a motor controller system, power is great but being realistic about what you need could save you money and weight in your system design. 
For people looking for reliable affordable conversions, my $0.02 is 10kw continuous and 80kw max would be a nice controller. Anything more than 80Kw is transitioning to sports car territory. 
Another thing to fully put 1.2Mw through a controller you need to have the ability to generate the 3000 amps of current even with A123 cells that is a pack 125 cells deep by 10 wide, or 1250 cells and that is for 20C.


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## Tesseract (Sep 27, 2008)

Nathan219 said:


> Has anyone built a vehicle that can actually use 1.2Mw or 1600hp the Shiva can produce?.. .



What, exactly, is the point of your post? It seems you are saying you don't need a lot of power so why should anyone else? That's, well, kinda pointless. Go put a ducktail on a kit car or something and quit hatin' on Shiva.


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## Nathan219 (May 18, 2010)

I want to see a vehicle that can actually produce and use that much power, it would be awesome, I am not hating. I am saying until someone fully utilizes your hardware what you have unleashed on this world cannot be appreciated!


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## Ziggythewiz (May 16, 2010)

Has anyone had difficulty finding a lower power controller than a Shiva to fit their needs? I can see the opposite being an issue in racing where there's no such thing as enough...

Also, I don't think any of us would be terribly adverse to having our cars classified as "sports cars". That's not a bad thing. 

You may not need to, but some people take their cars on the highway. 10kW seems pretty low, but does a grocery getter even need a continuous rating?


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## major (Apr 4, 2008)

Nathan219 said:


> I want to see a vehicle that can actually produce and use that much power, it would be awesome, I am not hating. I am saying until someone fully utilizes your hardware what you have unleashed on this world cannot be appreciated!


I heard about some guy who has put two of these monster controllers into his car and claims he will run it this Saturday and impress the world.


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## Nathan219 (May 18, 2010)

In my experience using my car, I get about 4.3 miles per kw that is 13kw continuous. What is your Leaf doing for you? 
Many people who are designing systems have hard time understanding how much power they really need vs how much they want, I blame our buying cars based on horse power.


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## major (Apr 4, 2008)

Nathan219 said:


> In my experience using my car, I get about 4.3 miles per kw that is 13kw continuous. What is your Leaf doing for you?
> Many people who are designing systems have hard time understanding how much power they really need vs how much they want, I blame our buying cars based on horse power.


This statement makes no sense whatsoever


> I get about 4.3 miles per kw that is 13kw continuous


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## Bowser330 (Jun 15, 2008)

A little timeline for you....For a period of time the DIY EV community was limited by controllers, batteries could push out and motors could handle more power than the controllers could provide....Then came Zilla which changed things, the 1000A+ controllers made batteries the limiting component. Then Zilla left the market and people begged, not kidding, begged, for someone else to build a 1000A controller. Evnetics responded. Then Drag racing started receiving national & international press and gained in popularity. So the market and interest for 2000A+ controllers became more prevalent. Hence they responded, again, and have been the only company to respond with such a controller...

Just as you use 30-40kw or 40-50% of your 80kw to accelerate, why is it any different than someone with a 1200kw Shiva using 480kw-600kw, still 40-50%, right?

Concerning cars that are using 600kw+/-120kw.....Lets see, we have White Zombie, the DC Plasma, EvWest's M3, lets not forget Ron A. with Warp Factor III, Shawn Lawless, basically tons of people from Nedra.


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## Qer (May 7, 2008)

Do I and my wife need three cars since we can only drive one each at the same time? Probably not, but it's practical (or just blatant laziness) to have cars reserved for different purposes.

Do we really need a big house with a separate dog house, a tool shed and a huge garage? Na, we made by quite perfectly in our 5 room flat we had before that, we couldn't even give the fifth room a purpose except being a combined dust collector and empty echo chamber.

Do I need a 19" rack full of huge servers that together consume about as much power as an ordinary house consumes to stay warm in the Swedish climate? Well, they're useful when I want to try out things in administrating UNIX-systems but since I don't work with it any more it's mainly for my own amusement, so no need.

Do I need this candy bag in front of me considering I'm already carrying around some bonus weight? Well, hush! 

"Need" and "want" are different things. No one (except possibly smaller trains) need 1600 hp, if I remember right even the biggest Volvo trucks make due with half that and even that borders to overkill.

No, I don't think anyone has managed to push 1600 hp out of a Shiva yet, I'm not even sure anyone has managed to reach 3000 Amps except extremely momentary. I am, however, convinced that now when there's controllers that can do it, someone will. It was the same with the Zilla 2k, there didn't exist batteries for a long time that could push even close to the current needed for getting full power out of a Z2k. It didn't stop the Z2k to be very successful on the strip since you still got the full torque at low RPMs even if you couldn't get the full power due to lack of good enough batteries.

1600 hp in a car is pure craziness, 2*1600 is fucking insane! But then, racing was never about being modest, reasonable or sane and when I saw YouTube-clips with the guys racing with Zilla 2k back in the days when Otmar were still running his own shop I thought that was completely crazy as well, cool but crazy, considering most people made do with Curtis 1231 and similar back in those days and just getting the batteries able to push even half the top current of a Z2k was extremely costly.

You're absolutely right, no one really need 1600 hp in a car.

...so?


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## Nathan219 (May 18, 2010)

Just affirming anyone who wants to build a monster please do so, and take lots of picture, and video because it will be very interesting. 
If on the other hand you want to build a car that performs the jobs you expect of your current ICE vehicle, I have found for a small four door car you need about 10-20kw continuous and more than 80Kw max equals more fun.


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## PStechPaul (May 1, 2012)

It is true that the car companies tend to advertise based on horsepower, as well as torque and speed and acceleration and handling, often in conjunction with aggressive driving and breaking laws (including sometimes the law of gravity). "Zoom-zoom". "Aggression in its most elegant form". All of this appeals to a "mostly male" preoccupation with competition and possibly to assuage a sense of inadequacy or frustration in the workplace which can be worked out on the public roads. And of course the big energy companies encourage this mindset and behavior because it uses more of their product. 

But in reference to the topic, it is sometimes better to design an EV with a motor, controller, and battery pack significantly in excess of what is really needed or can even be achieved. The thing is that all of these components will generally operate more efficiently when lightly loaded, so if you can afford the extra weight, space, and cost, it will save in operating cost. And the likelihood of failure should be less as well. It's all part of the bottom line.


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## rwaudio (May 22, 2008)

Nathan219 said:


> Just affirming anyone who wants to build a monster please do so, and take lots of picture, and video because it will be very interesting.
> If on the other hand you want to build a car that performs the jobs you expect of your current ICE vehicle, I have found for a small four door car you need about 10-20kw continuous and more than 80Kw max equals more fun.


It's all personal preference and driving style. Right now I have ~130kw it's not enough, it's fun don't get me wrong but not enough, installing the rest of my battery pack should get me in the 260-270kw range, and that "might" be enough. Mine is a daily driver and not a race car, but it doesn't mean we can't use short bursts of high power. I'd love a Shiva, even if it's more than my car needs just to get the feeling of _unlimited**_ torque.

I say well done evnetics!

**by unlimited I mean more torque than I could use on street tires..


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## Qer (May 7, 2008)

Nathan219 said:


> If on the other hand you want to build a car that performs the jobs you expect of your current ICE vehicle, I have found for a small four door car you need about 10-20kw continuous and more than 80Kw max equals more fun.


Yep. That's why the Soliton 1 and Jr are shelf products and the Shiva isn't.

Soliton Jr peaks at about 150 kW which is enough for most (all?) commuting cars and the Soliton 1 can reach 300 kW which is enough power for either sport cars or heavy trucks (or sporty trucks  ). The Shiva was never meant for reasonably needs, it's not a commuting controller. And then there's DIYguy being the exception to the rule, of course...

DIYguy excluded, Shiva is a variable short circuit for people that are prepared to jeopardize everything in their quest for performance without even a sideways glance at commuting! Noone is disagreeing with you, we're just trying to point out that you've completely missed the point with the Shiva. Of course noone _needs_ 1600 hp, but need is beyond the purpose of the destroyer...


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## Nathan219 (May 18, 2010)

My point is being missed. I am challenging the community to actually develop a system to produce and use 425V and 3000 amps. Example I have a 600V 400Amp plug and socket I could use to plug in a 20w lamp, but that wouldn't be a good use a resources now would it? Why does someone have to be wrong when they make a statement? Their are true facts, a road worthy modern car can be had with less than 100kw drive system, another fact is a 1200kw vehicle that can use all of that power is something I want to see, but I haven't seen anybody come close. 
Electric vehicles might be able to surpass ICE vehicle in acceleration competitions due to them being able to deliver more energy than you can extract from burning a fuel. 
I hope Warp Factor is up to the challenge. Good luck!


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## McRat (Jul 10, 2012)

Nathan219 said:


> My point is being missed. I am challenging the community to actually develop a system to produce and use 425V and 3000 amps. Example I have a 600V 400Amp plug and socket I could use to plug in a 20w lamp, but that wouldn't be a good use a resources now would it? Why does someone have to be wrong when they make a statement? Their are true facts, a road worthy modern car can be had with less than 100kw drive system, another fact is a 1200kw vehicle that can use all of that power is something I want to see, but I haven't seen anybody come close.
> Electric vehicles might be able to surpass ICE vehicle in acceleration competitions due to them being able to deliver more energy than you can extract from burning a fuel.
> I hope Warp Factor is up to the challenge. Good luck!


Would this be the right main contactor?

http://www.youtube.com/watch?v=Pz-TMpQjjAE


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## DIYguy (Sep 18, 2008)

I had a Soliton1 in my truck and it was adequate. . .but no thrill/set u back in ur seat/holly shit kinda ride. Now I have a Shiva with my 13" motor and I think it is "just right".  Of course I am not running 425 volts. . . but that is one of the reasons I wanted a higher amperage rated controller. Even with the CALB pack alone (it's getting an A123 "brother" soon) it sets u back in the seat and makes u say holly shit.


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## toyolla2 (Jun 21, 2010)

Nathan219 said:


> Has anyone built a vehicle that can actually use 1.2Mw or 1600hp the Shiva can produce? I usually use between 30-40kw to accelerate my Leaf up to speed. When choosing a motor controller system, power is great but being realistic about what you need could save you money and weight in your system design.
> For people looking for reliable affordable conversions, my $0.02 is 10kw continuous and 80kw max would be a nice controller. Anything more than 80Kw is transitioning to sports car territory.


Sorry Nathan but I also thought you were dealing us a slice of sarcasm 

Yes this topic, "Useable power", has been interesting as it offers a heads up for people who waste spend a lot of personal time in this field.


For one, it shows that there should be a division in the Forum that seperates off road track vehicles from those designs intended for the public roads. Generally I see that there is too much "contamination" of threads by "power users" which is at odds with the base objective to get more DIY EV projects on to the roads.


Modest designs of 15Kw (cont) are regularly dissed as being part of the golfcart fraternity, yet that power level should enable most vehicles to get on to most a major highways even though they are unlikely to be found camping out in the left lane.


For that matter it should be borne in mind that not too many Lithium ion battery packs exceed a useable 12Kwhrs of capacity when contemplating a range of 90% to 20% SOC for maximum durabilty. Others have even opined that exceeding 0.3C continuous discharge rate with some cell manufactures will noticeably foreshorten the number of charge cycles to end of life. After 18 months one user reported his smaller pack would deliver just 8-9 miles of range even though he had been discharging close to the 1.0C rate with 300% higher peaks only occasionally on hills and major highways.


So this fiction that it is OK to pulling 3C nominally and 5-6C not infrequently has to stop. Sure, some racers have admitted they intend to peak out at 9C during a 20min race, but they also accept their battery pack will be toast after twenty races.

Bottom line, that even with a 12Kw drain You probably have no more than 45 minutes of running time on a major highway.

Another statement that may get me into trouble is my opinion on motor sizing. When it comes to AC systems I have been seeing a preponderance of motors of at least 7.5Kw being considered . I haven't built an AC system myself yet, it's coming, but it stands to reason that no one should even be considering for a continuous rating with AC when the battery source can only deliver 12Kwhrs of energy. That is, 12Kw for one hour, and then you're done. Not my idea of continuous anyway.T

he relevant question to ask here is whether you can actually burn out or otherwise smoke a motor if said motor happens to be 95% efficient at processing that level of power. How much power does it take to raise the temperature from ambient to 200 deg C for Class H insulation ? I.E. is there enough time to do irreparable damage to the motor before the battery goes flat !


For industrial machines with short duration cycle times we will usually consider even a 30 second rating if it allows us to use a much smaller machine. Mill roll accelerators on printing presses comes to mind. 


Of course we can get any motor to start smouldering after half an hour if we choose one small enough but I know of no design that will admit to that so far. What we have most of the time are leviathan installations with 95Kg or more machines that suffer less than a 30 deg rise before the vehicle returns to its garage. I am not going to say I am accurate on all these figures but that is the flavor I am getting by reading perhaps thousands of posts and not a few blogsites either. 

Right now I am looking at a 7.5Kw SEW motor weighing in at 63kgs with 48.8N-m of torque.
Also on the table is a 3Kw Leroy Summer weighing in at only 25.7Kg with correspondingly lower 20N-m of torque.

This particular motor has an allowable short term 410% peak torque rating allowing it to deliver, during accceleration, 80N-m or almost twice the continuous rating of the larger motor. 

At only 1500rpm and that torque level this small motor will be absorbing more than 12.5Kw. However as I have mentioned before on this website a low rpm winding won't cut it in this application. The original 400V stator winding will need to be replaced with a high speed winding which will allow this same motor to deliver that same order of torque for a short time over many multiples of 1500rpm.

That is exactly how the EV1 did it and how Tesla and Nissan do it, even today, but at larger torques naturally. The blocker is that people won't consider a 3Kw machine to do this more pedestrian duty even though its propensity to harm the battery pack is much reduced.


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## Ziggythewiz (May 16, 2010)

toyolla2 said:


> Others have even opined that exceeding 0.3C continuous discharge rate with some cell manufactures will noticeably foreshorten the number of charge cycles to end of life. After 18 months one user reported his smaller pack would deliver just 8-9 miles of range even though he had been discharging close to the 1.0C rate with 300% higher peaks only occasionally on hills and major highways.
> 
> 
> So this fiction that it is OK to pulling 3C nominally and 5-6C not infrequently has to stop.


Source? ...


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## DIYguy (Sep 18, 2008)

toyolla2 said:


> For one, it shows that there should be a division in the Forum that seperates off road track vehicles from those designs intended for the public roads. Generally I see that there is too much "contamination" of threads by "power users" which is at odds with the base objective to get more DIY EV projects on to the roads.


Contamination. Perhaps u r the contamination. If u don't like it, don't read it. Power draws people. Wanna get the movement going, get some power. People like you are selling exactly the opposite of what will draw in the public. 



toyolla2 said:


> For that matter it should be borne in mind that not too many Lithium ion battery packs exceed a useable 12Kwhrs of capacity when contemplating a range of 90% to 20% SOC for maximum durabilty. Others have even opined that exceeding 0.3C continuous discharge rate with some cell manufactures will noticeably foreshorten the number of charge cycles to end of life. After 18 months one user reported his smaller pack would deliver just 8-9 miles of range even though he had been discharging close to the 1.0C rate with 300% higher peaks only occasionally on hills and major highways.


Baloney. Tell me about your car and your experiences with it.... or are you just a computer jockey?



toyolla2 said:


> So this fiction that it is OK to pulling 3C nominally and 5-6C not infrequently has to stop. Sure, some racers have admitted they intend to peak out at 9C during a 20min race, but they also accept their battery pack will be toast after twenty races.


Not fiction. I have pulled 5-6 c with my pack since I started driving it. I have no ill effects whatsoever. My normal draw is 1C or less though.
You also know little about racing it would seem. 9C? lmao. How about 90C?



toyolla2 said:


> Bottom line, that even with a 12Kw drain You probably have no more than 45 minutes of running time on a major highway.


How about 2 hours. . .?



toyolla2 said:


> Right now I am looking at a 7.5Kw SEW motor weighing in at 63kgs with 48.8N-m of torque.
> Also on the table is a 3Kw Leroy Summer weighing in at only 25.7Kg with correspondingly lower 20N-m of torque.
> 
> This particular motor has an allowable short term 410% peak torque rating allowing it to deliver, during accceleration, 80N-m or almost twice the continuous rating of the larger motor.


Why don't u just buy a golf cart. . . and when u do, use it away from the public so they don't think all EV's are like that.


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## LithiumaniacsEVRacing (Oct 9, 2010)

major said:


> I heard about some guy who has put two of these monster controllers into his car and claims he will run it this Saturday and impress the world.


Anyone know this guy? I would like to meet him. LMFAO! 

Saturday Lebanon Valley Dragway! 

One of two things could happen, I take the World record, or lipo cells will shoot into the sky like 4th of July!


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## EVfun (Mar 14, 2010)

...or you put your car on the roof


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## major (Apr 4, 2008)

Hi toy,

I'll pull out this one and address it. 



toyolla2 said:


> The relevant question to ask here is whether you can actually burn out or otherwise smoke a motor if said motor happens to be 95% efficient at processing that level of power. How much power does it take to raise the temperature from ambient to 200 deg C for Class H insulation ? I.E. is there enough time to do irreparable damage to the motor before the battery goes flat !


First off, class H insulation is good for 180ºC. Typically 140ºC rise over ambient is used for rating purpose. Higher temperature doesn't necessarily burn it up, but rule of thumb is every 10º over 180 cuts insulation life in half. So running at 200ºC may reduce the magnet wire coating down to 5,000 hours which would still be adequate for your average EVcar, I guess. But it may have other adverse effects on things like bearing lube or brush wear if it is a commutator machine.

As to motor efficiency, 95% in uncommonly high for EV motors, especially DIY jobs. I think you'll find most motors used in conversions show a peak efficiency of around 85% and then the actual loading my not coincide with that peak. So the amount of power converted to heat in the machine isn't a simple percentage calculation. Much of the motor heat can come from overload at reduced voltage (and speed) experienced during accelerations from standstill or hill climbing. This condition tends to be worse for smaller motors.

The question of the time rating for motors is interesting, and complex. I used to be involved in establishing these types of ratings for industrial motors. Depending on the type of industry and the type of motor, standards exist. Most NEMA motors do have the continuous ratings. Forklift traction motors used a one rating. Forklift pump motors use a duty cycle (like 20%) or 10 minute rating. Depending on the motor design, one hour can equate to continuous because the temperature stabilizes within one hour at rated load. Or for some other design like totally enclosed non ventilated, continuous rating temperature stabilization can take 3 or 4 hours. 

The typical EV conversion battery pack will contain enough energy to damage the motor by overheating or "smoke" it when the motor is overloaded. Overload can come from headwind on the highway, road incline, heavy load, under inflated tire, dragging brake, aggressive driving, etc. Depending on the particulars, results could be a few degrees too hot to actual flames and failure ranging from a few minutes to hours. For example, you would certainly damage the motor running it at 4 times the one hour rated load for 15 minutes although the battery would likely support it.

Regards,

major


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## PStechPaul (May 1, 2012)

toyolla2 said:


> Yes this topic, "Useable power", has been interesting as it offers a heads up for people who waste spend a lot of personal time in this field.
> 
> For one, it shows that there should be a division in the Forum that seperates off road track vehicles from those designs intended for the public roads. Generally I see that there is too much "contamination" of threads by "power users" which is at odds with the base objective to get more DIY EV projects on to the roads.


It seems you think much like I do. I am looking for efficiency and modest cost as the bottom line. But there seem to be a lot of "hot rodders" who want awesome power, and I think (or hope) that those are in the minority. The public roads are meant for safe and convenient transportation, not speed contests, and the growing number of "accidents" and road rage incidents attest to the consequences of HP escalation.



> Modest designs of 15Kw (cont) are regularly dissed as being part of the golfcart fraternity, yet that power level should enable most vehicles to get on to most a major highways even though they are unlikely to be found camping out in the left lane.




There were some threads a while back that questioned if a 10 or 15 HP motor would be enough for an EV. I did not think so at the time, and thought 20-30 HP was just about right for a modest size 4-5 passenger sedan or (compact wagon) such as my Saturn SL1 and SW1. And although a smaller motor may work, a 25HP motor and controller can be had for under $1000 or so, and the rest can be spent on batteries. There is not much efficiency penalty by going a bit larger, and it's better to have some reserve if you need it.

[snip battery drain comments]



> Another statement that may get me into trouble is my opinion on motor sizing. When it comes to AC systems I have been seeing a preponderance of motors of at least 7.5Kw being considered . I haven't built an AC system myself yet, it's coming, but it stands to reason that no one should even be considering for a continuous rating with AC when the battery source can only deliver 12Kwhrs of energy. That is, 12Kw for one hour, and then you're done. Not my idea of continuous anyway.The relevant question to ask here is whether you can actually burn out or otherwise smoke a motor if said motor happens to be 95% efficient at processing that level of power. How much power does it take to raise the temperature from ambient to 200 deg C for Class H insulation ? I.E. is there enough time to do irreparable damage to the motor before the battery goes flat !


AC Motor overload ratings are similar to other electrical devices like transformers, where duty cycles, maximum ON times, and core temperature are the salient factors. A continuous duty motor can provide its specified power 24/7 even under less than ideal conditions and a simple thermal switch or sensor is all that is needed to assure minimal risk of failure over many years of use. Since overloads are generally based on torque, which is proportional to current, and I^2R losses predominate, a 140% overload requires a 50% duty cycle and a 200% overload is 25%, and at 400% it is 1/16 or about 6%. Anything above 200% is generally for very short durations under a few seconds, so not applicable to EVs except for quick spurts.



> For industrial machines with short duration cycle times we will usually consider even a 30 second rating if it allows us to use a much smaller machine. Mill roll accelerators on printing presses comes to mind.




The 30 second rating is usually 140% to 200%. YMMV.



> Right now I am looking at a 7.5Kw SEW motor weighing in at 63kgs with 48.8N-m of torque.
> Also on the table is a 3Kw Leroy Summer weighing in at only 25.7Kg with correspondingly lower 20N-m of torque.
> This particular motor has an allowable short term 410% peak torque rating allowing it to deliver, during accceleration, 80N-m or almost twice the continuous rating of the larger motor.
> At only 1500rpm and that torque level this small motor will be absorbing more than 12.5Kw. However as I have mentioned before on this website a low rpm winding won't cut it in this application. The original 400V stator winding will need to be replaced with a high speed winding which will allow this same motor to deliver that same order of torque for a short time over many multiples of 1500rpm.
> That is exactly how the EV1 did it and how Tesla and Nissan do it, even today, but at larger torques naturally. The blocker is that people won't consider a 3Kw machine to do this more pedestrian duty even though its propensity to harm the battery pack is much reduced.


It seems rather unusual to consider the choice of motor to protect the battery pack. Each has a job to do and a set of specifications and needs individual protection. You can make judgment calls to balance risk of component degradation with maximum possible performance, but I'd want the ability to get everything I could (without blowing up) rather than be limited to what is most efficient and least damaging. I want to be notified of the possible deleterious effects of "pushing the limits", but not have the system shut down or prevent me from extracting maximum performance in an emergency situation. Or for fun, if the cost is worth it.


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## McRat (Jul 10, 2012)

Trivia for those living on the edge:

Halon is still available for racing applications. 

This remains the most powerful by far for stopping electrical fires without killing humans in the area.

There are two flavors:

1301 - Released as a gas, this is for enclosures. It is safe to 7%, at 10% it causes sluggishness.

1211 - Released as a stream, this is for open areas, range of about 10 feet in still air. Ditto on the toxicity.

Carbon dioxide is not safe or recommended for enclosed areas. It is lethal at much lower levels, it forms ice and liquid water, is far less effective, and causes driver impairment at much lower concentrations.

Halon is a CFC, hence it can deplete ozone, so it's use is pretty much limited to high risk fire suppression, but it is still legal.

It does not work like CO2 or other suppressants. It disables the ability of flammable compounds bond with oxygen. This makes it an order of magnitude better at stopping electrical and liquid-fuel fires. While it works on paper and wood, water works better.

If you are playing high power EV's you should have Halon systems in place.

If you have an open vehicle, spray your batteries and controller with 1211. If you are enclosed, use 1301. I use 1301 for ICE engine and fuel areas, and also inject it directly into the engine. For the cabin, I use aqueous foam. If I were EV, it would get 1301.


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## McRat (Jul 10, 2012)

FantasyLand:

If you wanted a sustained 481vdc at 3250 amps for a minute, you could use 400lb of these:

http://www.hobbyking.com/hobbyking/...ech_A_SPEC_5000mah_10S_65_130C_Lipo_Pack.html

For a mear $30,000.

For a short burst, they will go 6500 amps (4000HP?). So you'd actually run 2 Shiva's, and 8 Warp9's, 4 front, 4 rear.

You'd put them in a <4 sqft frontal area streamliner, with a Cd of <.15 with AWD and traction control, and set the World's Absolute Speed record for a wheel driven car.

You'd push it quickly to 100mph using a 7000lb 1000HP 4x4 (less than 1/4 mile required), then start dialing up the voltage to whatever traction was available. You'd use a fifth wheel system. You would not be pushing the batteries hard for very long, and could perhaps top 550mph which AFAIK has never been done. If you could get enough traction by using downforce, it would come close to breaking the sound barrier, but I doubt you could. There is enough power and duration to do it, but not enough distance or traction.


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## PStechPaul (May 1, 2012)

An even wilder fantasy: 

Pack a jet engine with LiPo cells and water, and mount it on your dragster (or directly to you, to save weight). Short them all out with a huge contactor, and the flames and steam from the explosion and Lithium-H20 reaction will propel you across the finish line in record time (provided your aim was good and your aerodynamics keep it going straight...


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## McRat (Jul 10, 2012)

PStechPaul said:


> An even wilder fantasy:
> 
> Pack a jet engine with LiPo cells and water, and mount it on your dragster (or directly to you, to save weight). Short them all out with a huge contactor, and the flames and steam from the explosion and Lithium-H20 reaction will propel you across the finish line in record time (provided your aim was good and your aerodynamics keep it going straight...


Or, find a racetrack that points North/South. The car body is made of iron, and is a huge electromagnet. It probably would not work, but at least you'd end up with a nice compass when you were done.


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## PStechPaul (May 1, 2012)

Design a special racetrack with oversize MRI magnets...

Maybe a NHRA Supercollider for an EV demolition derby.

They might even reveal the Higgs Bosom!


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## DIYguy (Sep 18, 2008)

McRat said:


> Trivia for those living on the edge:
> 
> Halon is still available for racing applications.
> 
> ...


I think the problem with Lipoly (not lifepo) is that the metal oxide provides the oxygen during thermal run away. Excluding air, or surrounding with halon, will do nothing to stop it.


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## Ziggythewiz (May 16, 2010)

Why not just install a supermag launcher like an aircraft carrier catapult?


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## drgrieve (Apr 14, 2011)

I drive a 85kw peak ICE car. Not that it would push that out now as it's 15 years old.

It weighs around 3000 lbs with me in it with full tank.

I've driven it over 100 mph with no problem, I rev it from the stop lights and change at 5000 rpm to get nowhere first.

So I would agree with OP that a 80 kw peak EV is absolutely fine for a commuter car.

But I don't grin.


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## McRat (Jul 10, 2012)

DIYguy said:


> I think the problem with Lipoly (not lifepo) is that the metal oxide provides the oxygen during thermal run away. Excluding air, or surrounding with halon, will do nothing to stop it.


Best guess:

Nothing reactive is going to work well on a runaway pack. That needs to be proactive. A system should be in place to shut it down before the temperature becomes unsafe, not after.

Normal suppression for metal fires is "D" class powders, but they would do very little except make it more dangerous by insulating the pack with a hard shell. Think firecracker.

#1 is to get the driver out alive. #2 is to minimize damage.

To get the driver out, a firesuit and Halon would be the best choice. If the fire was not a runaway battery, it would do job #2 without damaging the equipment.

Flooding the individual cells with water will stop a runaway pack. You can't carry enough water onboard to handle >200lbs of batteries though. You need a firetruck. And you'll do some unintended damage with water.

Aqueous foam is not a good choice, nor are CO2 systems. They don't pack nearly the punch of the same weight of Halon. 

I will probably test Halon (used correctly) on a runaway when I get around to it, but we are talking about a $1000++ test. I think the FAA testing was invalid for EV's, since it involved just small, low voltage battery packs, not high amp, high voltage situations. They did not attempt to use the cooling effect of 1301, and only used short bursts of 1211, not sustained. However, the FAA still requires Halon on board last I heard.


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## toyolla2 (Jun 21, 2010)

_It seems rather unusual to consider the choice of motor to protect the battery pack. Each has a job to do and a set of specifications and needs individual protection. You can make judgment calls to balance risk of component degradation with maximum possible performance, but I'd want the ability to get everything I could (without blowing up) rather than be limited to what is most efficient and least damaging.



Months later this statement would seem to be prescient of the problems that Nissan has been having in the desert climes of Arizona where an independant range test was conducted. A route was run which navigated through several interchanges while maintaining a 60mph average speed for 83 minutes. I find it hard to believe the driver could avoid the need to pump the Leaf's 80Kw motor a few times to the detriment of the battery ? A battery which was already being cooked through its underside while passing over a continuous strip of asphalt , baking hot from the mid day sun. It is likely that a 40Kw motor could have completed the course with less energy expenditure, I can't help feeling.
_


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