# Anybody with the ADC 6.7" 8hp motor? - why is mine so wimpy?



## TheSGC (Nov 15, 2007)

What voltage are you running it at and what controller are you using?

I had a 6.7" ADC K99-4007 in my EV that was 8HP continuous at 72 volts, but it sucked so badly at that voltage that I went straight to 96 volts because it can handle it. At 72 volts I could get to about 25 MPH decently, then all the power was lost.

The performance jump was HUGE at 96 volts I could do 45 MPH (74KPH) no problem in 2nd gear, but I did add a blower cooler to the motor to help it with the hills. I later upgraded to a ADC 9" FB1-4001a, but that was because I happened to come across it locally for dirt cheap and couldn't resist.

I had this motor, just with a different shaft: http://www.evparts.com/prod-MT2113.htm


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## frk2 (Jan 2, 2009)

72v , Curtis 1209b . I have the exact same motor as the link you provided. What kind of amps did you run it with DECENT acceleration, just out of curiosity? I have to intermittently push 150-200amps to get some juice out of the motor . I dont think i can do 96 volt as there is no place to shove the batteries in my tiny car - also upgradnig the controller, charger, DC/DC coverter is going to be too expensive I would guess... Can the Zivian NG1 be reprogrammed DIY to accept 96v?


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## TheSGC (Nov 15, 2007)

I could push 220 battery AMPs with the pedal to the floor, but I had a Kelly KDH09401 and I never say more than that. After a good 15 or 20 seconds it would drop down to 160-180 battery AMPs with the pedal to the floor, and I am willing to bet that would also be motor AMPs because I could only get that high with 100% duty cycle, i.e. pedal to the floor.

A lot of it has to do with gearing and the torque the motor can produce at certain RPMS. At 72 volts the K91 motor can take 110 AMPs for 1 Hour, 185 AMPs for 5 minutes and 130 AMPs for 30 minutes. 

You will have decent torque for acceleration up to 2800 RPMs, then it will slow down. It will be most efficient at 3900 RPMs, but it will take a while to get there. At 96 volts I had decent torque up to 3800 RPMs (40 MPH for me) and most efficient at 5000 RPMs, but I highest I ever went was 4800 RPMs (50 MPH).

When no one was around, I would accelerate with 120-130 AMPs, but if I was in traffic I would be pedal to the floor and no one would complain.

I have since upgraded to a Zilla 1K-LV and what a difference. Though, it would probably melt a 6.7" motor in no time.


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## frk2 (Jan 2, 2009)

Thanks! That puts things in perspective. I think they should stop marketing the 6.7" motors and the Curtis 1209B low voltage (72v) setups since they are simply not practical. If they can't power my tiny Suzuki Alto I dont know what CAN they power  Going to try upgrade to 96v. I have a Curtis 1231C standing by - if I can only reprogram the Zivian and get 4 more batteries somehow I should be good to go.


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## TheSGC (Nov 15, 2007)

frk2 said:


> Thanks! That puts things in perspective. I think they should stop marketing the 6.7" motors and the Curtis 1209B low voltage (72v) setups since they are simply not practical. If they can't power my tiny Suzuki Alto I dont know what CAN they power  Going to try upgrade to 96v. I have a Curtis 1231C standing by - if I can only reprogram the Zivian and get 4 more batteries somehow I should be good to go.


You will see a huge performance increase with upgrading to 96 volts.

72 volt systems are more for motorcycles and go karts. I originally thought about a 72 volt EV, but went to 96 volts because the cost wasn't much more, compared to jumping to 120 volts. 96 volts seems to work fine, but my batteries are not so happy in this winter snow so I have to limit my Zilla fun quite a bit. 

The Zivian should be programmable up to 96 volts, and adding more batteries can be a challenge but worth it.


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## frk2 (Jan 2, 2009)

I think I have no choice but to upgrade sometime down the line - however gunning my car to 150-170 amps all the time also seems to work somewhat  However I realize that removing that clutch was a bad idea since I do need the 2nd,3rd and 4th gears a lot - leaving it in 3rd is not cutting it!


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## madderscience (Jun 28, 2008)

Well lessee... 72V at 150 amps equals about 15 horsepower. So to put things in perspective, even when gunning it you are using very little power; an advantage of a small car.

It does take considerably more amps to accelerate or climb a hill vs. running on the level so don't be surprised that you need amps to accelerate. As an example, with my car, if I am cruising at 30 mph on a level, smooth road I only need about 35 battery amps to maintain it (1985 toyota MR2, 126V battery, ADC 9" motor). However I easily pull 150 to 200 amps to accelerate at a reasonably brisk speed to get there. And, if I climb a 10% hill at 30mph, I am pulling more like 300 battery amps just to maintain speed.

How well do your batteries maintain voltage when accelerating? As they sag, you will of course lose power. If you can't get more batteries in, can you get better batteries in that don't sag as much?

If your motor is not overheating, it is probably sized well for the vehicle. 

There are higher amp rating 72V controllers. I believe alltrax has one that can do 600 amps. The 1209B is a 400 amp controller.

How are the tires? can you put better tires on it, or pump them up more to reduce rolling resistance? Can you change to a slightly smaller diameter tire? this will increase torque (at the expense of top speed)

Do the brakes drag? Even just a little brake drag will kill your range. How is the suspension alignment?

Not familiar with the climate in Karachi but the 1209B is an air cooled controller. If you have a hot climate, you may need a better heat sink than whatever you are running. Something finned, with active (fan) cooling. Locate the controller where having the car sit in the hot sun won't cook it. Controllers cut back on the power to save themselves if they get too hot.

Also, are the motor brushes fully seated? If the motor is new, it is going to take several hundred miles for them to break in. As it does, you should see torque improve noticeably. So if it's new, don't give up on it just yet.



Good luck


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## frk2 (Jan 2, 2009)

madderscience - Thanks a lot. That does put things in perspective. Batteries maintain voltage well - never sagging to below 66V even on high draw.

Tires are good 'hard' radials and inflated to 40psi. a wheel alignment job was recently done on the car so thats not the issue. I am already using the smallest possible diameter (11"). 

I dont know about the brushes - will see! I guess i am just used to driving powerful cars so this feels a little wimpy. 

I have been able to get 70km in range while not dipping below 72.0 volts ( 6.0v per cell ) which should theoretically mean about 65% discharged. I think i should be able to go 85km at 80% DOD which is fine.


I doubt the controller temp is a problem since the controller rarely goes above 40C (I can comfortably touch it)

However - whats your Wh/Km rating? Is mine reasonable at 136.8Wh/Km (218Wh/Mile) for such a small car which never exceeds 60Km/h ( 37.5 mph )


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## madderscience (Jun 28, 2008)

70 Km (~43 miles) is pretty decent range for a 72V car, so I'd be guessing you do have the chassis dialed in pretty well. 

128Wh/Km or 218 Wh/mile are pretty good numbers too. I don't know how much stop and go or what kind of roads you are driving; terrain, road surface and traffic can make a big difference. I'm assuming that is a battery-to-wheels number. If it is wall-to-wheels then it is excellent.

In "city" driving around here (Seattle, WA, USA) my speeds range from about 35Km/hr to 70Km/hr. On mostly flat terrain I get about 250 WH/mile or 155Wh/Km. If I drive into some of the hilly areas, it can be around 330 Wh/mile. If I can actually acheive an "ideal" (peak effiency for my car) drive (about 45mph, no stops, no hills) then I get down to about 200Wh/mile or a little less. My car weighs about 3400lbs or 1600Kg. All my Wh/mile numbers are battery-to-wheels measurements. All roads are asphalt or concrete around here and most of them are in tolerable shape though I've got some serious pothole ranches near my house.

Sounds like you just need to see if that motor is fully broken in yet. If not be patient. If so, your best bet might be a higher amp rating controller, unless you want to upgrade everything to 96V.

One other thought: I don't know whether the curtis 1209b is like my 1231, but if it is, then there is a "ramp" adjustment which affects how quickly the controller responds to changes in throttle input. The 1231 at least is set pretty sluggish, and it makes it seem even less gutsy because of that. I haven't adjusted mine (yet) but a lot of people do. Refer to your controller's documentation to see if there are any options around that I guess.

Cheers


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## frk2 (Jan 2, 2009)

Thanks. My EV's brakes gave up on me and a visit to the local friendly mechanic revealed that my front calipers are partially jammed and so is one of the wheel bearings!!! Thats good news for me  Meaning i should be able to extract even more range hopefully!

The problem is I would expect my car's Wh/Km rating to be significantly better than yours - since it ways only 700-800kgs with the batteries. I hope thats true. Those are battery to wheel numbers evaluated using a Ah meter.


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## TheSGC (Nov 15, 2007)

I installed my new suspension system this weekend as I was able to lower my Wh/Mi from 312 to 270 Wh/Mi and my Civic is about 1230 KG and I drive 35 MPH with lots of hills, just for comparison.


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## frk2 (Jan 2, 2009)

Just out of curiosity how would a suspension help you get better Wh/Mi rating? My suspension has gone to the dogs with the added weight it bounces / bottoms out all over the place!  but why would that effect anything other than handling/comfort?


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## TheSGC (Nov 15, 2007)

frk2 said:


> Just out of curiosity how would a suspension help you get better Wh/Mi rating? My suspension has gone to the dogs with the added weight it bounces / bottoms out all over the place!  but why would that effect anything other than handling/comfort?


Due to all the battery weight, my rear wheels were bent in adding a lot of excess drag because the stock suspension couldn't take it. It's called camber, I believe, and if the camber is anything except 0, it cause lots of added drag and tire wear. I also had this nasty effect of my headlights no longer shining on the road so I really couldn't drive it at night.

I have installed an after market Skunk2 Racing coil over and strut setup that can handle loads of weight and it has been working great. The stock suspension was 80 lbs per inch of spring compression and the Skunk2 is 450 lbs per inch of compression, a huge difference.


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## Jimdear2 (Oct 12, 2008)

TheSGC said:


> Due to all the battery weight, my rear wheels were bent in adding a lot of excess drag because the stock suspension couldn't take it. It's called camber, I believe, and if the camber is anything except 0, it cause lots of added drag and tire wear. I also had this nasty effect of my headlights no longer shining on the road so I really couldn't drive it at night.
> 
> I have installed an after market Skunk2 Racing coil over and strut setup that can handle loads of weight and it has been working great. The stock suspension was 80 lbs per inch of spring compression and the Skunk2 is 450 lbs per inch of compression, a huge difference.


 
You may be on the right track with the camber idea because camber chage will cause a toe change. Anything other then zero toe will cause a lot of tire scrub.

Just a thought, do you think that changing the angle (raising the rear) might have changed the air flow around the car as well as trapping less air under the car. Big opening at the front small outlet at the rear kind of thing.

Just curious, those of you with the math and backgound to figure that out, what do you think?


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## TheSGC (Nov 15, 2007)

Jimdear2 said:


> You may be on the right track with the camber idea because camber chage will cause a toe change. Anything other then zero toe will cause a lot of tire scrub.
> 
> Just a thought, do you think that changing the angle (raising the rear) might have changed the air flow around the car as well as trapping less air under the car. Big opening at the front small outlet at the rear kind of thing.
> 
> Just curious, those of you with the math and backgound to figure that out, what do you think?


I didn't think of it that way, but I really don't drive fast enough for air drag to do much. I am usually under 35 MPH during my drives, but with this new suspension and controller I am thinking about trying some highway speeds.


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## Jimdear2 (Oct 12, 2008)

TheSGC said:


> I didn't think of it that way, but I really don't drive fast enough for air drag to do much. I am usually under 35 MPH during my drives, but with this new suspension and controller I am thinking about trying some highway speeds.


TheSGC,

My motto "Don't Think . . . Do"

Maybe thats why I'm always in so much trouble.

Be interested to know _How Much Better_ the new controller is.

Have fun


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## TheSGC (Nov 15, 2007)

Jimdear2 said:


> TheSGC,
> 
> My motto "Don't Think . . . Do"
> 
> ...


I ran my EV with only the Zilla for 3 weeks, and I have measured a steady improvement of 7% over the Kelly. I had 333 Wh/Mi from the Kelly and 312 Wh/Mi from the Zilla, and now 270 Wh/Mi with my Zilla and new suspension. I contributed the controller efficiency to the fact that it could produce the high AMPs to maintain speeds on hills (300+) where the smaller Kelly could not (220-240) and ended up burning up that power in the motor while I dropped to lower than walking speeds.

frk2-
I had my brakes go out on me last September. I was on my way home from school, cruising at 35 MPH when I heard a little thump, smelled something foul and my EV dropped down to 25 MPH in no time. I ended up running my pack so low that I coasted into a elementary school about 4 miles from my house, went to call a tow truck, but found an outside plug and got permission to charge. I got real lucky on that one, and it made me think I should try and find other places willing to let me/other EV'ers to do quick emergency charges.


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## DavidDymaxion (Dec 1, 2008)

For many IRS rear suspensions, when the suspension is very compressed, the contact patch moves side to side more on bumps. When the tire is vertical, as designed, the tire patch doesn't scrub as much. Here is something I don't know, does bottoming out hurt your range? I could see a better suspended car might roll more easily over bumps than one bottoming out all the time.

No fancy math for you, but something better: Salt Flats racers almost universally lower the front ends of their cars as much as they dare. They generally argue that overall lower is more aerodynamic. However, I did have one email me that he found his car (I think it was a Mitsubishi Eclipse) had a sweet spot, and going too low actually hurt his top speed. For us in the EV world, better top speed would translate to better highway range for us.


Jimdear2 said:


> You may be on the right track with the camber idea because camber chage will cause a toe change. Anything other then zero toe will cause a lot of tire scrub.
> 
> Just a thought, do you think that changing the angle (raising the rear) might have changed the air flow around the car as well as trapping less air under the car. Big opening at the front small outlet at the rear kind of thing.
> 
> Just curious, those of you with the math and backgound to figure that out, what do you think?


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## kubvan (Dec 9, 2014)

madderscience said:


> How are the tires? can you put better tires on it, or pump them up more to reduce rolling resistance? Can you change to a slightly smaller diameter tire? this will increase torque (at the expense of top speed)


I have just electrified my Kubvan, it originally came with 13 inch tires, I upgraded to 14" and BWM rims while it was still a diesel for a better footprint and 13's were getting harder to find. 

Now that its electric top speed is not important to me as I just use this vehicle around the neighbourhood, what percentage improvement in torque or range do you think you gain by reducing tire size from 14 to 13 ? I am guessing a narrow tire, high pressure of course would be best.

Sounds like an easy thing to do if there is a real battery / hill climbing / performance boost.









Thx Kubvan


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