[PStechPaul]

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.

[rwaudio]

Originally Posted by Nathan219

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..

[Qer]

Originally Posted by Nathan219

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...

[Nathan219]

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!

[McRat]

Originally Posted by Nathan219

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

[DIYguy]

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.

[toyolla2]

Originally Posted by Nathan219

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.

[Ziggythewiz]

Originally Posted by toyolla2

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? ...

[DIYguy]

Originally Posted by toyolla2

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.

Originally Posted by toyolla2

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?

Originally Posted by toyolla2

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?

Originally Posted by toyolla2

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. . .?

Originally Posted by toyolla2

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.

[LithiumaniacsEVRacing]

Originally Posted by major

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!