Manta II and Kelly Controler

[techfab]

Hey All,

I have posted for specific advice in a few different threads on this site and received great feedback and am hoping I can get a little more.

My son and I are building a stretched version of the Spidercarts Recluse that both he and I will ride. We are going electric (in part because we live in California and my hippie neighbors would frown on anything but). I want it to be powerful enough to be fun for both of us now and for him to be able to grow into higher performance (by adding battery or adjusting throttle throw). I knew electric would be more expensive; but, I am shocked at how much more when you move past 1000W.

Anyway, I have learned a lot on the subject here and have done a lot of internet shopping over the last several weeks and keep coming back to the same motor/controller combo.

I am considering this motor:

http://www.ebay.com/itm/Manta-2-10-...tek-MT-Pattern-Permanent-Magnet-/301067430388

and this Kelly controller:

http://kellycontroller.com/kdz4820024v-48v200aseriespm-p-951.html


From the research I have done, it seems the motor is a re-manufactured version of the discontinued Briggs and Straton Etek motor. I can get it cheaper than listed. I haven't pulled the trigger since I can't find much feedback on the motor and it seems like it is modded by a mom and pop shop here in CA. Also, no warranty; so it seems a bit sketchy; but, based on my research, it seems to provides a lot of bang for the buck/size if it performs as advertised.

My questions:

Does anyone have any knowledge of this motor?
How do the specs look to y'all?
Do you see an issues with the motor/controller combo.

I plan to run it at 36v. I will obviously need some beefy AH.

 

[itsid]

Hm.. not a fan, voltage control by 'sliding battery poles' @ 100 Amps ??
really...???

IYAM motors should be fixed voltage and variable amperage not the other way around..
but that's just me...
Yes you can set the kelly to voltage controll.. BUT
that means there is no voltage cutoff anymore..
so you could fully drain your batteries (and thus render them useless)

So yeah, not a fan.. still possible though.

specs look consistent to me (if not made up they're actually pretty good)
The motor controller combo should not cause an issue, other than my own private concerns about battery life and maybe inconsistent drainage (that'd hurt the cells)

just an idea:
Try to trace down a golf cart for example with a rotten shell and a working motor.. that's specifically made for "moving a vehicle" and it'll have more than enough power and comes with it's perfect matching controller as well
(Plus sometimes they're cheap to get )

'sid

 

[dcastillo]

I agree with the golf cart motor (thats what I use)...
The big issue Im finding (trying to get a bigger motor) is finding one with a male shaft and close ended, not the typical female spline open ended design... the one i have now is from 1982...

does anyone know an easy way to mod the open ended design to mount a sprocket to it? I have lots of connections for golfcart motors, but all have the open ended design and female shaft....

 

[techfab]

Thanks itsid and d. I agree on the golf cart motor; but, have the same concern as dcastillo with most designed to accept a male shaft and requiring support on the business end.

I did not realize that the Manta motor could only be controlled by adjusting the voltage. The chart that lists the performance with rpm, amps and torque seemed to indicate otherwise to me. No?
Please keep in mind that almost everything I know about DC motors I learned from reading your posts itsid.

 

[itsid]

from what I can tell by the spec graphs, you set the RPM via voltage alone
(well nominal rpm that is)
and not via amperage...

Maybe I just don't understand their auction text *shrugs*
Or maybe they just don't know themselves (which might in fact be the reason)

The controllerless setup as pictured for example is the WORST BS I've seen in a while..
no matter how careful you are, an open 48V terminal with the capacity to unload close to 500 Amps into your or worse your children's body...

That is roughly 40 times more than you'd need to be killed in an instant...
'nough said..

Anywhoo,
at that point in time I'm not actually taking this ad or the seller for granted I'm afraid,
so whatever they said, might or might not be true at all

Sorry, that's a good price, and the specs read really good..
yes PM brushed motor.. that's not actually pretty but good enough,
since the thermoswitch should keep the magnets from overheating.
(overheated magnets are non-magnets afterwards, thus the motor is dead for good)
And if that's all true it's woth a try I'd guess...

personally I'd NOT buy it though,
voltage control is for RC-stuff, not electric vehicles IMHO;
and based on their auction text I'm not exactly sure they know what they do at all
with that in mind.... I doubt the data plots and basically everything else as well..
and that's when it gets too expensive to give it a try for my taste

But again, that is my humble opinion, so *shrugs*
what should I say

'sid

 

[techfab]

I am going to heed your opinion as it is in line with my gut on this thing. Thanks again.

 

[wesleyb82]

Hm.. not a fan, voltage control by 'sliding battery poles' @ 100 Amps ??
really...???

IYAM motors should be fixed voltage and variable amperage not the other way around..
'sid

Sorry to hijack this thread but I have to ask sid to clarify here bc this made me do a double take. The way I understood this stuff, the motor controller using PWM (Pulse Width Modulation) to pulse the motor on and off quickly (no voltage, full voltage) and the frequency of this switching determines the effective voltage the motor receives after which amperage is determined based on the power consumption of the motor or the load under which the motor is experiencing. Amperage comes after you apply voltage not the other way around... or so I thought. So I am confused when you say "motors should be fixed voltage and variable amperage not the other way around." Is this even possible, how is this possible, what controllers do this and why should it be this way?

Btw I too was scratching my head after seeing the sliding scale in the Manta II description when I found it a while back.

[The current I in amps (A) is equal to the power P in watts (W), divided by the voltage V in volts (V): I(A) = P(W) / V(V)]

 

[itsid]

Sorry to hijack this thread but I have to ask sid to clarify here bc this made me do a double take. The way I understood this stuff, the motor controller using PWM (Pulse Width Modulation) to pulse the motor on and off quickly (no voltage, full voltage) and the frequency of this switching determines the effective voltage the motor receives after which amperage is determined based on the power consumption of the motor or the load under which the motor is experiencing. Amperage comes after you apply voltage not the other way around... or so I thought. So I am confused when you say "motors should be fixed voltage and variable amperage not the other way around." Is this even possible, how is this possible, what controllers do this and why should it be this way?

Btw I too was scratching my head after seeing the sliding scale in the Manta II description when I found it a while back.

[The current I in amps (A) is equal to the power P in watts (W), divided by the voltage V in volts (V): I(A) = P(W) / V(V)]

Exactly a PulseWidthModulation is alway full power on or full power off..
both voltage AND amperage of course;
BUT the coils are still under power because of the very tiny pulses (or pauses to be precise).
So measuring a motor under load, you will read full voltage all the time, but a variable amount of amperage..

thus it's fair to say that common PWM controllers use Amperage to limit the power out, not Voltage

And, most motors are designed to run at such a single fixed voltage to provide the best possible efficiency.

And there we get into the realms o the unspeakable business of winding motors.. I'm clueless I'm afraid,
I have a very rough idea on what affects what, but to be honest... that's still very greek to me.

'sid

 

[Wheelchock]

Similar Project

I used a permanent magnet motor (Montenergy ME-0708) with an alltrax controller at 48 volts. Plenty of torque - I'm at 9:1 on the reduction (12 tooth sprocket on the motor to an 18 tooth sprocket on the jack shaft and 10 tooth from the jack shaft to 60 tooth on the drive shaft). Its a hoot to drive. I'm now interested in going a little faster - I'm going to take it down to 6:1 by changing the motor sprocket to 18 tooth.
Looking at the specs on that Ebay posting, it looks like they may have copied and pasted specs from the same motor I'm using. There is data and/or links available on this website: http://www.evdrives.com/Default.asp
I don't see a golf cart motor as a viable option unless it has a standard shaft with keyway and end bell on the drive end. Some of the older golf cart motors such as Taylor Dunn are built like that, but there may be other drawbacks such as availability of parts like brushes and then there is mounting (not flange mounted nor does it have feet), and some of the older motors turned out to have aluminum field windings which can add connection problems.

 

[wesleyb82]

Again, sorry to hijack this thread but Wheelchock do you have more details about your build?? I will be attempting a build very similar to this sometime in the future and have been preparing for a while now. I am curious which batteries you are using, what your run time/range is, if you specifically setup a kart with no swing arm and if so what was the reason for it and impressions afterwards and last what is your final speed with jackshaft. Thank you!

 

[dcastillo]

Awesome setup!!!!
I currently have a 2Kw golfcart motor, but really wish I could afford the motor you got!!!!
-Danny

 

[techfab]

Wheelchock. Nice setup. I am not planning on using a jackshaft. I am going to run direct from the motor sprocket to a live axle sprocket. Do you see any downside to that? I have not selected the motor yet; but, am looking at the Motenergy options. I am looking for a bunch of wheel spinning torque with limited top end and should be able to get 8:1 without the added complication of a jack shaft.

 

[Wheelchock]

A Little History

I'm new to go karts. A buddy of mine was cleaning out his garage and was going to toss this go kart. I told him that I would take it and see what I could come up with. It came disassembled with no engine.
I'm an electric kind of guy anyhow, so I decided to convert it to electric. I've done a few electric projects in the past including converting a Mitsubishi van to an all electric commuter car. Mostly I've played around with golf cart running gear.
When I got this kart, I realized that it was too short, so I added about 10" to the length. As far as no suspension; it appeared that the oversized tires on the back would provide enough give for what I wanted to do - pull the kids on their sleds when it snows. I felt like I was going to have a heart attack last year running down the street pulling their sleds!
I used the jack shaft because the original sprocket (10 tooth) had a 3/4" bore and the chain that it came with fit the 60 tooth driven sprocket. It seems to be an odd size (41 I think) and I couldn't find a similar sprocket that would fit the chain and the 7/8" shaft that the motor has. Since the jack shaft was part of the original set up I used it and drive it with size 40 chain. I get most of my parts from an industrial bearing supplier that also has industrial type of sprockets and chains. I intend to change the sprocket out tomorrow - I'll let you know how it goes.
The batteries are simple deep cycle marine batteries off the shelf at Costco. I haven't had much time to drive this cart. I'll get the top speed and battery run time once I change the sprocket and drive around a bit.

 

[Wheelchock]

I changed out the sprocket on the motor to an 18 tooth. Now 1:1 on the motor to jack shaft. That puts me at 6:1 overall.
This thing has plenty of torque and pretty good speed. I did not have anyone clock the speed as it was too cold out to stay too long. I will get that soon and post it.
The batteries held up well for the approximately 1 hour that I was out there. However the battery gauge that I installed (with LED indication) seems to have some kind of logic circuit in addition to just indicating battery voltage. It seems unreliable. I put a digital multimeter on it and I dropped a couple of volts while out goofing around (52 volts down to 50 volts).
This is the first time that I've spent much time on it. A couple of observations: The ride is rougher than I would like (i.e. no suspension) - I thought that the big soft tires would make up for that, and they did somewhat, but it is still a little stiff. Maybe letting some of the pressure off of the tires might smooth it out a little. Also, the straight axle makes it tough to make a tight turn. The rear wheels just want to make it go straight. This will probably be OK in the snow - the main reason for the build.
At this point I'm very impressed with the motor and controller. Keep in mind that the alltrax controller is programmable. At this point I'm at 80% maximum output. This can easily be changed by connecting my laptop to the controller and making the adjustments.
Let me know if you have specific questions. Like I mentioned, I will post the speed and battery performance when I have specifics.

 

[wesleyb82]

Very cool thanks for the info! We currently have a small solid frame electric kart with a solid axle so we are very familiar with what you are describing. Our observations though have been that although the ride is hard, a rigid frame gets the power down!!

I've read in other places (http://www.diyelectriccar.com/forums/showthread.php?t=21394&highlight=deep+cycle+marine) that marine deep cycle batteries do not last in these applications but hopefully yours hold up.

Do you happen to have a video of it running? I'd like to see the power this thing has. Thanks for the info again and sorry again to techfab

 

[master50tech]

I am in the middle of an electrification

I am converting a yerf dog two seater to electric with my kids. Using the exact same Kelly Controller. I am using a 3 HP electric 4 pole motor, and will keep the jackshaft intact, replacing the comet clutch with a chain with another 3:1 reduction. I do not anticipate any problems using a brushed DC motor with PWM. Kelly recommends sizing the controller bigger than what is needed for the motor. Still have not hooked the controller to the motor, will do soon. Sadly the motor has an odd tapered shaft which I am still trying to figure out the best way to get a sprocket on, motor is from an electric motorcycle. The batteries I am using are Powersonic 35 Ah, 4 for 48 volts. The have very good specs and if you only let them deplete no more than 50%, you can get hundreds of recharge cycles, they have grapsh on this. Hope this helps.

 

[master50tech]

Wheelchock, do you have 20 inch diameter tires? My kart is a yerf dog 3203 with full front and rear suspension, and I am going 3:1 motor to jackshaft for off road hill climbing capability. I figure this gives me almost 20 MPH, as this motor wind up to almost 6000 rpm. Can you climb some decent hills with your cart? What kind of current are you pulling at different scenarios, flat, hilly, at start?

 

[Wheelchock]

The tires are 18". I had a buddy follow me to check the speed. It was 18 - 20 MPH on level ground. Hill climbing is good - I'm on paved streets though. I have not taken it on any off road trails.
Plenty of torque - I can easily get more speed. I'll play with the sprocket ratio. I'm going to try 5:1 and see how that goes. I ordered some sprockets, maybe they'll be here by next weekend.
I do not have an amp meter on it. I'll look around my garage and see if I still have a shunt and meter that would work.
You mentioned a tapered shaft. Cushman had a tapered shaft arrangement with a 3 HP motor. They may have had a sprocket set up in some of their installations. That motor was rated 3 HP @ 36 Volt and 4 HP @ 48 volts.

 

[master50tech]

Thanks for the heads up on Cushman, will take a look, do not feel like grinding or cutting the shaft. Techfab, one of the benefits claimed by the Kelly controller is current multiplication, which means at low RPM it will pull less current from battery than it sends to motor at low RPM. Itsid mentioned that PWM puts full voltage at the motor just on and off, which is kind of true, but as current averages, so does voltage, and the inductance of the windings may smooth it out, even without current multiplication. I am going to throw a scope on it when I get the chance to see, Kelly has a graph of there current multiplication, in the FAQ, good information there.

Cheers