DIY Electric Car Forums banner

421 - 440 of 650 Posts

·
Registered
Joined
·
1,760 Posts
Wait.... so the LEFT plot (the one i marked up) was the one that Qer/Tess provided to Cro after they processed some data that Cro provided too them...Thanks again guys!

The RIGHT plot was, if i recall, the plot from Cro's drift run, which is not apples to apples to the dyno run where the 600hp was acheived....
Fyi, both plots are generated by me. That's why they look so alike... :D
 

·
Registered
Joined
·
3,218 Posts
Yeah, I think it was. Maybe he had the current limit turned down :confused: But that doesn't seem like his style :)
I had to re-read our e-mail exchange because I couldn't remember the details, but by doing a sort on the log file used to create the above drifting/racing plot the highest battery current was 968A and peak power was 298kW.

Cro did ask why he wasn't able to pull 2000A; I couldn't tell him exactly but I suggested he review all of the limiting parameters the Zilla lets you configure and see if one of them was coming into play. My guess was motor voltage limit as it is easy to forget.
 

·
Registered
Joined
·
887 Posts
Discussion Starter #424
This log was recorded on a drag race



I actually believe that it was this particular run:

http://www.youtube.com/watch?v=t-5GNi7TjV4

You can see how the wheels spin at the start - matches the rising and falling RPMs on the graph.

The other graph was recorded on the dyno. I don't believe that the controller setup was a lot different. The motor RPM was climbing a lot more quickly at the dyno, the run was much shorter and at a higher RPM than the drag race - maybe that's the reason for the higher power. I don't believe it's battery related since we had a higher voltage battery at the drag race (we had to remove 12 series strings after it).

Both graphs where created by Qer (thanks a lot!!).

I'm not so sure what to do now... This setup is really good, I would have to make a lot of changes to get more power. I can add one more motor but that wouldn't help much. I'm not a fan of paralleled motors (remember my fried Kostovs?) and I don't have enough voltage for two of them in series. A 600V controller would be perfect for me - two of these motors in series with more cells for a 600V battery pack. That would be a killer. A pity that I have a old and stinky BMW, not a shiny hot-rod :D

(Just kidding, NHF)
 

·
Registered
Joined
·
887 Posts
Discussion Starter #425 (Edited)
And one thing that is VERY interesting... We compared the dyno data with the controller logs to calculate the efficiency. It turns out that the motor is 80-90% efficient at high RPMs!! (high voltage, low current)



OK, some don't believe that those dyno numbers are accurate so we'll test it again. But IF the dyno worked properly (I believe it did since it measured 420 whp for the BMW M6) this is a great result and a BIG BIG win for DC technology.

EDIT: Displayed is a run with a lower current/power setup. We're not so sure which log relates to which dyno run because they look very similar except this one (long flat power graph because the controller reached the current limit and stayed there). I forgot to mark the logs so they got messed up. I'll be more careful next time...
 

·
Registered
Joined
·
4,958 Posts
Thats pretty typical for most brushed motors actually. Generally they peak above 85%. I don't see why that efficiency couldn't be found at higher power settings as long as you don't saturate the iron.
 

·
Registered
Joined
·
3,218 Posts
I...A 600V controller would be perfect for me - two of these motors in series with more cells for a 600V battery pack.
It's like deja vu all over again for me... I just explained why pushing the voltage rating higher is so difficult in an e-mail to Todd.

If you've ever noticed how a Blackberry or cellphone interferes with a TV that is close by then you have seen an example of radiated noise getting into the electronics and f'ing things up. Now imagine a source of noise that is 10^5 times more powerful, and even worse is that it is only a few centimeters away. That's a motor controller for you. There are two types of noise, btw: one is proportional to voltage ("Blackberry-like") and the other is proportional to current (umm... power line hum is the best common example I can think of). The higher the voltage the more like a radio transmitter a controller becomes, in other words.

A pity that I have a old and stinky BMW, not a shiny hot-rod :D

(Just kidding, NHF)
Nah, has nothing to do with your BMW or what you are doing with it. The big problem is that you are in Europe and that makes beta testing difficult. We'd simply overwhelmingly prefer to work with people as close to us as possible. Even Todd is a bit farther away than I'd like for the purposes of evaluating a controller that is several times more powerful than the Soliton1.

Secondly, Todd doesn't need a controller right now. His schedule and our lack of one - :p - seem to be meshing together well, in other words. You are doing good work promoting EVs and as much as I'd like you to buy our stuff I'd rather you keep doing what you do which might inspire others to do something similar. Yeah, I know that sounds like a load of crap but at least in my case it really is true. Well, I also want you to continue to enjoy the best that the dinosaur offers, such as its arcane serial interface, tendency to fault in the middle of a race, etc... Sooner or later you will come to your senses ;)
 

·
Registered
Joined
·
4,458 Posts
...just explained... in an e-mail to Todd... how a Blackberry or cellphone interferes with a TV that is close by...
I still think it's hilarious that my TV was buzzing from my Blackberry checking my email, as I was reading that exact part of his email! I think Jeff set the whole thing up. :)



...Even Todd is a bit farther away than I'd like for the purposes of evaluating a controller that is several times more powerful than the Soliton1...
Ya never know, that could change - you guys have beaches, bikinis, and palm trees, three of my greatest needs in life! :D



...Secondly, Todd doesn't need a controller right now. His schedule and our lack of one - :p - seem to be meshing together well, in other words...
That's the thing. We have the same goals for it, Big Sol seems to be in roughly the same places on our priority lists, and we have been progressing on similar timelines. It's just a win-win deal for developing something totally ridiculous, and one of those situations in life where paths happen to cross at the right time. I think they're actually moving a bit faster than I had hoped. ;)

You're actually a major part of the process too though Cro, because your efforts and willingness to share will help make sure the end result is off the scale. The way I see it, this is about helping to nurture and promote a tiny newborn industry - EV racing. I'd like to think of us as all being on the same team, doing our individual parts. We're really competing against the momentum of the overall automotive market and pure chance. We have to get our collective foot in the door and establish our version while the opportunity is there, or we'll be talking about how we almost made it work this time - like EVs lost to gas at the beginning of the last century. That momentum and "chance" swing very fast and if we don't make a strong showing the next great thing will knock us out of contention.
 

·
Registered
Joined
·
541 Posts
Just wanted to point something out...

It appears as though that even with the Soliton-1 (Race 1400A)...500hp is capable @ 4500rpm!!!...with 270V sagged...I!
Hi Cro, et al,
You might have seen my motor theory thread:
http://www.diyelectriccar.com/forums/showthread.php/dc-motor-theory-and-model-39931.html
I have applied it to Some Warp11HV measurements: 72 Volt dyno data emailed to me back in February by CroDriver. I reduced those data to a saturation curve, including the 1400 amp point noted above. The motor resistance of 27 mOhm and brush voltage of about 3 volts yields the power curves attached.
I can't get iron losses from those data, but if I can get the Zilla dumps and dyno data, I might do better and analyse your whole system.
Gerhard
 

Attachments

·
Registered
Joined
·
887 Posts
Discussion Starter #430
Here's our new video. Enjoy watching it.

http://www.youtube.com/watch?v=eVB-Tszp_LY

Hi Gerhard.

Thanks for those graphs. Could you send me your mail address in my inbox please? I'll send you the logs if you want.

Btw. Admins - If you're listening... Please upgrade the vBulletin software so we can post embedded youtube clips so the forum members don't have to view the clips directly from youtube. This looks much better too. Thanks.
 

·
Registered
Joined
·
1,199 Posts
Cro,

Nice video, considering the number of direction changes during the build the car came out fantastic.

A thought on your broken drive trains. If you watch the Zombie, the Current Eliminator and other top dog drag only EVs and bikes you will see that they leave the line with only enough torque applied to move the vehicle up to the point of tire slip, no tire smoke, almost like traction control. Tire smoke is lost power (it does look good though:D) power you can use later in the run.

I don't know if it is just fine tuning if the hairball, additional computer inputs or just great drivers. Could be any one of them

If you start looking at torque limiting and ramping in the power slower, you might break fewer parts.

Don't mean to critisize you efforts, just commenting from expereiance, haveing broken a few parts in my younger days. lets face it anything worth doing, is worth doing to the limit.:D

I love (need) your battery (or at least half of it). I'm the fool who has put a 13 inch GE onto a 1350 pound mini pulling tractor/sand dragger (for sure worth overdoing). Right now it's 72 volts, until I can afford Headways or maybe Kokums. I can only carry 250 pounds of batteries and need 350 or so volts and at least 1000 amps for 15 or so seconds.

Since you have some real world time with Headways I might shoot you a question now and then, hope you'll answer.

Of course you couuld just ship me half your pack and let me figure it out myself:D.

Keep on turning them tires, watch a couple of the videos of the Current Eliminator on some of it's record runs. You hear the contactor clack, a tire chirp and it's gone. I guessing, but they must set the controller up for the bite at each track.

Keep having fun, I love watching and remembering the good old days,
Jim
 

·
Registered
Joined
·
887 Posts
Discussion Starter #434 (Edited)
Thanks JRP and speedily. I've tried embedding with the Youtube function of the forum [YOUTUBE}{/YOUTUBE] (just with the correct brackets) but it doesn't work.

Cro,

Nice video, considering the number of direction changes during the build the car came out fantastic.
Yes, many unexpected things happened. Thanks.

A thought on your broken drive trains. If you watch the Zombie, the Current Eliminator and other top dog drag only EVs and bikes you will see that they leave the line with only enough torque applied to move the vehicle up to the point of tire slip, no tire smoke, almost like traction control. Tire smoke is lost power (it does look good though:D) power you can use later in the run.
Nah, I like to burn the rubber at the start, that makes all those petrol heads around the starting line jealous :D I don't care about half a second more or less, at least for now. We're now upgrading the mechanical part of the car (two speed zero shift transmission and differential from scratch) so we expect better results at the next race. I expect low 12 sec or high 11.

Keep having fun, I love watching and remembering the good old days,
Jim
Thanks. I'm glad you like it.
 

·
Admin: 'one of many'
Joined
·
4,838 Posts

·
Registered
Joined
·
89 Posts
Thanks JRP and speedily. I've tried embedding with the Youtube function of the forum [YOUTUBE}{/YOUTUBE] (just with the correct brackets) but it doesn't work.
Nice video right there. Did you try to use the complete url or just the last part?


So only use the part of the url behind the =. :) In this case:
PHP:
[MEDIA=youtube]eVB-Tszp_LY[/MEDIA]
So the admins do not have to make any adjustments. :)
 

·
Registered
Joined
·
1,626 Posts
We're now upgrading the mechanical part of the car (two speed zero shift transmission and differential from scratch) so we expect better results at the next race.
Nice video
I'm also really interested by a 2 speed transmission without clutch coupled with a single 11'' dc motor.
I will probably start a new thread about 2 speed performance transmission soon.

So with zero shift transmission you cannot go in reverse simply with reverse the motor rotation!! It's the main principe. You probably need a third gear.
Please give us few detail about the trasnsmission you thinking use. Thanks.

 
421 - 440 of 650 Posts
Top