# Running a 13-inch DC Motor? Please share...



## toddshotrods (Feb 10, 2009)

I'm trying to think forward to practical battery pack configurations, controllers, etc, for the Inhaler. I am not planning on any serious racing, just a lot of smoky fun, but want to get an idea how this might play out. All my previous/devious plans were centered around racing, at all costs. That's easy - just design to exploit the absolute maximum potential of strongest link, and continuously upgrade/replace all the stuff you break in the process. 

Now, I am trying to get a feel for what's necessary for normal street fun. I think my final weight is going to come out around 1200lbs, so if I can get an idea of what some normal 13-powered vehicles are doing, I can make some assumptions.

Objectively:


How much current are you actually seeing (motor and battery)?
What voltage are you running?
What overall gearing ratio?
What types of speeds (mph and rpm) are you doing?
What does your vehicle weigh?
Transmission/no transmission?
How much motor current to spin the tires (do a burnout)?


Subjectively:


How does it feel (especially compared to any other motors, if possible); double bonus for the impression of others you've given a ride?
Would you describe the "pull" (applied torque) as smooth, aggressive, brutal, your own words...?
Does it feel like it's running out of steam on top (rpm); if so, around what RPM?
Why did you choose a big 13?


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## Frank (Dec 6, 2008)

I don't think there's many 13's out there. I would be looking at 11's...


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## toddshotrods (Feb 10, 2009)

Frank said:


> I don't think there's many 13's out there. I would be looking at 11's...


There aren't but there are a few nicely done conversions, and racers. I think there's one in an S10, with Soliton control.

Already swapped the 11 out for the 13, it's a done deal - just wanted to peek at other's notes before I started creating my own...


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## Frank (Dec 6, 2008)

My bad, I lost track of this project and 148 pages is too much to go back through!


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## toddshotrods (Feb 10, 2009)

Frank said:


> My bad, I lost track of this project and 148 pages is too much to go back through!


It was on hold for a while, and belonged to the community workshop I was in. Now it's mine again, and back on the front burner.

I usually tell people to start from the last page and read backwards!


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## jackbauer (Jan 12, 2008)

I've a 13" in the land yacht. Just waiting on the rest of the cells to complete the pack but even running just 10 cells (32v) it laughs at two tons of German automobile in 5th gear


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## toddshotrods (Feb 10, 2009)

jackbauer said:


> I've a 13" in the land yacht. Just waiting on the rest of the cells to complete the pack but even running just 10 cells (32v) it laughs at two tons of German automobile in 5th gear


Thanks Jack! Easily moving 2 tons, in 5th gear says a lot. That's the kind of subjective feedback I was hoping for. If possible, please chime in again with more when you get up to full voltage.

What kind of batteries are you running?


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## rochesterricer (Jan 5, 2011)

Paging DIYguy. Might wanna read through the later pages of his build thread, if you haven't already:

http://www.diyelectriccar.com/forums/showthread.php/good-ohmn-here-we-go-23492.html


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## jackbauer (Jan 12, 2008)

CALB CA180FI x 50


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## toddshotrods (Feb 10, 2009)

rochesterricer said:


> Paging DIYguy. Might wanna read through the later pages of his build thread, if you haven't already:
> 
> http://www.diyelectriccar.com/forums/showthread.php/good-ohmn-here-we-go-23492.html


Thanks for posting that. I was trying to remember who and where that was - it's been quite a while since he posted any updates, and I couldn't remember what to look for. I was trying to lure him out here. 




jackbauer said:


> CALB CA180FI x 50


Thanks.


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## rochesterricer (Jan 5, 2011)

You could always bump his thread and give him the link to this one. He seems to still log in regularly. Would be a nice excuse for him to post an update.

Edit: nevermind, I went ahead and did it lol.


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## toddshotrods (Feb 10, 2009)

rochesterricer said:


> You could always bump his thread and give him the link to this one. He seems to still log in regularly. Would be a nice excuse for him to post an update.
> 
> Edit: nevermind, I went ahead and did it lol.


Thanks and good work - that also made me realize something - I wasn't subscribed to his thread. I seem to have accidentally unsubscribed from some of my favorites threads, including one of my own!


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## toddshotrods (Feb 10, 2009)

From reading DIYguy's and Jack's results and comments, I think I am succeeding in my mission to build an absolute bonkers little hot rod! A 23" long, 13" motor, in a 1200lb, 90" wheelbase, go-kart?!  That'll work. 

I should be able to run insanely low (numerical) gearing in the diff, giving decent top end, the tires a slim chance of finding something resembling traction, and unsuspecting passengers a severe case of whiplash! 

Better upgrade the personal injury coverage my insurance policy, and get some waivers...


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## DIYguy (Sep 18, 2008)

toddshotrods said:


> I'm trying to think forward to practical battery pack configurations, controllers, etc, for the Inhaler. I am not planning on any serious racing, just a lot of smoky fun, but want to get an idea how this might play out. All my previous/devious plans were centered around racing, at all costs. That's easy - just design to exploit the absolute maximum potential of strongest link, and continuously upgrade/replace all the stuff you break in the process.
> 
> Now, I am trying to get a feel for what's necessary for normal street fun. I think my final weight is going to come out around 1200lbs, so if I can get an idea of what some normal 13-powered vehicles are doing, I can make some assumptions.
> 
> ...




3000 amps.


toddshotrods said:


> [*]What voltage are you running?


211 nominal


toddshotrods said:


> [*]What overall gearing ratio?


3.55:1 in direct drive. 2.77:1 in OD


toddshotrods said:


> [*]What types of speeds (mph and rpm) are you doing?


just do the math I guess. (I know, u need tire size)


toddshotrods said:


> [*]What does your vehicle weigh?


4300 lbs approx.


toddshotrods said:


> [*]Transmission/no transmission?


direct + GV over drive with Lenco reverser.


toddshotrods said:


> [*]How much motor current to spin the tires (do a burnout)?


This depends on so many things. I can actually smoke the wide tires much easier than my LRR tires. This is due to side wall height/stiffness and patch elongation . . . or lack thereof. Pavement type, temperature etc.



Subjectively:


How does it feel (especially compared to any other motors, if possible); double bonus for the impression of others you've given a ride?
Would you describe the "pull" (applied torque) as smooth, aggressive, brutal, your own words...?
Does it feel like it's running out of steam on top (rpm); if so, around what RPM?
Why did you choose a big 13?
[/QUOTE]

I had a 9" motor in the truck before with a 5 speed trans clutch-less. I also had the Soliton before the Shiva. But I can compare the 13" with 1000 amps vs the 9" with 1000 amps. If I picked first or second gear with the 9" vs direct drive with the 13", I would say, subjectively, that the g-force was similar BUT and this is a big but, the duration of that force with the 9" and 5 speed was very short compared to the 13" direct drive. If you were to race the two heads up, it would be an easy win for the 13" cause it holds the torque longer. Of course if you had a CVT with the right ratios, you could do the same thing. Another point is that the 13" can take more repeated high current events in the same time frame due to its higher continuous HP rating.

I chose the 13" coz I centred my build around a heavy vehicle and higher current/lower voltage (compared to most 1/4 mile cars). This was really driven by my original build component selection. . . and migrating to higher performance. If your voltage is on the low side, you need to pass a lot of current for decent performance. Make sure you base your calcs on sag'd voltage, not nominal.

I think the motor selection should be based mostly on vehicle weight, and then voltage. (talking DC here of course) You can do similar things with different size motors, but need to get creative with transmission requirements. Heavier vehicles do better with larger motors. Duty cycle has a lot to do with it also. It's one thing to run high power for a short duration, and another to run continuously. To build a good perfmorming street/strip EV is really quite a challenge because it is not just focused on 10 or 12 seconds.

As for how it feels, most passengers say in a rather loud voice. "Wholly F!#$%!% Shit !!! or "WOOOOAAAAAHHH" !! something like that.


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## toddshotrods (Feb 10, 2009)

Really awesome feedback DIYguy, thanks! 

I'm in the middle of moving right now - will add some thoughts, comments, questions, when I can...


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## DIYguy (Sep 18, 2008)

FWIW, I think a 13" motor is overkill for this weight vehicle. I mean, your motor must weigh close to 400 lbs. That's a third of the final vehicle weight. My 13" is 325 lbs and it has both aluminum end bells and I think it's slightly shorter than yours. For torque requirements, an 11" should be more than enough . . and for thermal concerns (duty or continuous hp) you would have to do quite a few high current events with no additional cooling to have issues. With such a light vehicle, a 13" seems like a lot of motor to me. . . subjectively.


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## JRP3 (Mar 7, 2008)

DIYguy said:


> FWIW, I think a 13" motor is overkill for this weight vehicle.


That's the point


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## toddshotrods (Feb 10, 2009)

DIYguy said:


> FWIW, I think a 13" motor is overkill for this weight vehicle...
> 
> ... an 11" should be more than enough...
> 
> ...With such a light vehicle, a 13" seems like a lot of motor to me. . . subjectively.





JRP3 said:


> That's the point


What he ^^^ said! 


That really is the point. It's American hotrodding at its finest, 21st century style. The ICE equivalent is a 426 Hemi, with a blower, in a 32 Ford roadster.






DIYguy said:


> ...I mean, your motor must weigh close to 400 lbs...
> 
> ...My 13" is 325 lbs and it has both aluminum end bells and I think it's slightly shorter than yours. For torque requirements...


It was reportedly 350lbs on the pallet (info from seller and shipper), but I suspect they never really weighed it. I wouldn't be surprised with 400lbs. Steel end bells, and the overall motor length (with end bells, no shafts) is 23". It's an absolute beast. 






DIYguy said:


> ...and for thermal concerns (duty or continuous hp) you would have to do quite a few high current events with no additional cooling to have issues...


We really need an "evil grin" smilie here. 







DIYguy said:


> ...That's a third of the final vehicle weight...


Oh, stop with the compliments already, you're making me blush!


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