Motenergy ME 1003 users, e-buggy builders please chime in!

electron bom

electron bom

1 W
Joined
Oct 30, 2014
Messages
54
Location
Raleigh, NC
I searched the forums and have found scant mention, much less personal report on the nuances of this Brushed PM motor. If anyone has personal experience with this motor please share. I'm nearing the end of my build and I'm not quite sure what to expect. On paper it should perform well. The motor is going in an off-road buggy that has been repurposed for tarmac.

The original ICE made 9hp/13ftlbs somewhere around 7500 and 5500rpms respectively. It utilized a CVT which I never opened so I'm ignorant to the actual gearing. Curb weight was right at 500lbs. Top speed was ~35ish mph and acceleration was pitiful, so out went the original setup.

To start, I will be using LiFePO4 CALB 100AH cells in 16s configuration. Assuming ~90% efficiency and assuming I can pull 200A constant with out issue, I should be good for 9.2Kw or 12.4hp. At nominal voltage of 51.2V the ME1003 will be doing 2200rpms, if my Kw figure is correct then that means the motor will be producing 29.6ftlbs. My current gearing is 2:1 so I'm expecting 25whp and 60wtq. The kart's current configuration tips the scales right at 530lbs so on paper this all looks nice, but I'm assuming that the ME 1003 will be happy pulling 200A continuous at 48V. Anyone with e-kart or ME1003 experience please chime in! Here are some pics.

p4pb11695220.jpg


p4pb11695219.jpg


p4pb11695218.jpg
 
WOW!

I assume this is one of those dune buggy karts with the upper cage removed. Is it intended as street transportation or recreational? That'll probably affect what people think.
 
Just for thrills. Ideally I would like it to be somewhat overpowered, but I assume I'll have to run 60 or 72V for that. I'm just trying to gain some insight as to how 48V/200A will perform. I've read conflicting statements on what this motor will handle for constant current. The popular power diagram floating around the internet shows this pulling only 130A @ 48V and hitting right around 92% efficency, some e vendors claim is will handle 160A constant, but I've also read that it will handle 200A constant.

Here is the graph
ME1003_Curves.jpg
 
I have seen some and heard of some failures with the PM DC brushed motors on karts, motorcycles and ATVs. Most of those were Agni or the earlier version of your motor using the smaller comm and half # of brushes. The increase of brush/comm a few years ago certainly helped.

On your question about continuous duty: You can't really run continuously at 200A, can you? Your battery will be drained in less than 30 minutes. However, that could be long enough to smoke that motor. And what load will cause 200A steady? Towing something or going uphill? Usually there is a cycle of high current for accels and then low current for cruise and then no current for decels and stops. So it's tough to say say if the motor will survive. You need to keep watch over it, or have a spare.

Doesn't look like there is a differential. It might be difficult to steer on pavement.
 
I fantasize often about participating in a hill climb event. Kart is 530lbs +190lbs (me) 720lbs uphill for 1-2miles depending on course. I also plan to resituate the battery bank in order to reinstall the passenger seat. With a passenger, total vehicle weight could be over 900lbs. I'm completely ignorant about this motor's actual performance, but I'd expect it to come quite close to 200A draw moving that much weigh up a hill at high throttle inputs. Again, this is just conjecture on my part. Your input is much appreciated.
 
Well if it's THRILLING you want, for a few dollars more this offers a lot. People call it twice as good. Of course that's next time, you're supposed to be becoming a junkie for this.

http://www.electricmotorsport.com/ev-parts/motors/brushless-motors/pmac-ds-me0913-brushless-pmac-motor-24-96v-5000rpm-12-kw-cont-30-kw-pk.html

Or since this includes a controller and miscellaneous it's not so expensive to go AC.

http://www.electricmotorsport.com/ev-parts/motors/ac-induction/ac-12-kit.html
 
I really like the look of that ME0913. Its only rated 500W more than the ME1003, but spins 2000rpm higher. I can only imagine the gear ratios possible with that thing. I guess I'll try to sell a kidney now so I can afford the battery bank to support 96VDC :shock: I appreciate the links. It seems the inference is that thrilling isn't possible with my ME1003 and alltrax 7245?
 
There's thrilling and then there's thrilling. When I was 6 I was thrilled I was RIDING a bike and neighborhood kids a bit older than me weren't yet.

You're gonna want more, and MORE, and MORE!
 
What is a power:weight ratio that would be thrilling?

I started out relating power figures to what I know, small displacement turbocharged gas engines. I had a small turbocharged gas engine in a car with a wtq:lb ratio of 1:6 (5th gear dyno pull) and that car was very brutal. I know comparing ICE to electric is a waste of time, so I look toward the Tesla S.

I know the Tesla Model S performance has thrilling acceleration. It has a 310kW rated motor making 443ftlbs, a single gear ratio of 9.75:1 and it weighs 4647lbs.
That gearing means the Tesla performance is making 4319ft/lbs at the wheels yielding a wtq:lb ratio of 1:1.08 :shock:

My little kart's 60wtq and 530lb curb weight yields a 1:8.33 wtq:lb ratio. Comparing this figure with the Tesla, it sounds like my kart will be a slouch with its power to weight being 8 times weaker than the Tesla. I realize the Tesla is world class performance and a vehicle with 1/2 the power would still be interesting to say the least. Am I going about this the wrong way? Any ideas?
 
Your understanding of power/torque/gearing etc is a little off. ,
Gearing will change theTorque available at the wheels, but it won't alter the Power available.
Also , if you compare torque figures at the wheel, you need to consider the effective wheel/tyre diameter in order to get any true performance comparison .
You also need to consider the torque / rpm profile when trying to compare electric to ICE.
 
I'm purposefully concerning myself with wheel torque to vehicle weight because gearing plays such a large role in drive characteristics. I suppose not accounting for drive tire diameter makes this a rough comparison, but answers to my question are subjective at best. A suitable benchmark is the Tesla S performance and after looking at numbers on paper, it seems that even 1/2 the performance (wtq:lb) is well beyond the reach of my setup. I was hoping to discover some first hand accounts, but its difficult to even get an opinion on this.
 
electron bom said:
. I suppose not accounting for drive tire diameter makes this a rough comparison, .
Click to expand...
:shock: rough !... More like totally inaccurate !
The same torque on a wheel of half the diameter would double the acceleration !
A dyno will automatically account for tyre diameter, but when you start calculating comparisons, you need to factor in these differences.
 
True statement about the wheel diameter, but I think you're misunderstanding my question. I'm interested to know what people here find to be a 'sporty' performance minded power to weight for their respective EV. I consider top speed and acceleration equally when defining a vehicles performance. Power to weight will dictate how much of both a vehicle has. Changing tire diameter will just slide the vehicle along the acceleration/top speed continuum. The only reason I'm figuring gearing into the equation is to eliminate that as an unknown variable in order to keep the question direct and simple. This thread is producing unexpected results :p I'm looking for answers along the lines of, "Hey I have an EV making X power to the wheels in a vehicle that weighs X lbs and it does X mph and 0-60 in X" I'm hoping I don't come across negatively as I do appreciate everyone's responses thus far.
 
I'm posting this for reference in the event anyone pursues a similar project and is keen to see some figures. Here is a short video of the kart.

http://www.dailymotion.com/video/x2d5z4j_electric-kart-test-run_auto

The numbers: ~16hp and 36ftlbs (assuming 90% efficiency). 3.9:1 gear ratio, top speed is 29mph, 19" tires. My rudimentary scale yielded a kart weight of 538lbs.
It is more fun than the gas engine, but definitely not thrilling. I would imagine that at 72v it will 'wake up' since the motor is only turning 2000rpms at 48V.
 
Hi,

I recommend that you get rid of the Crappy And Lame Batteries and get a Chevy Volt Pack.
 
I just gotta know about your wheels on this thing. Are they on the stock hubs? If so, what wheels fit? Front and back match the bolt pattern? (I've found some of those buggys don't.) If not the originals, where did you get replacement hubs?
 
Stock hubs are 4x110 front and 4x137 rear.
I put adapters on the rear to net a 4x110 pattern, thus I can uniformly fit the common ATV lug pattern.
I got the hubs from adapter kings. The fronts have spacers which I believe I got from some random internet ATV parts dealer
 
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