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  #21  
Old 05-02-2016, 06:22 AM
JokerBen321 JokerBen321 is offline
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Thank you for listing that controller. I am 80% sold on that one because of its price, but still going to keep my eye open for a bigger, beefier motor. If any of you see a 2000w + motor for $300 or under and a controller that works with it, please let me know.

Thanks again,
Ben

PS. I am looking at this motor(a little expensive, but has a stupid amount of power which would be fun).

http://www.robotmarketplace.com/products/NPC-4200.html

If anyone sees a controller for this motor, please let me know because I am clueless as to what controller works with what motor (I am huge in RC models but these larger scale things just seem more confusing).
  #22  
Old 05-02-2016, 08:00 AM
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that is what I meant talking about BS ratings..

"almost" 4hp... continuous draw of 215Amps @ 24Volts (5180 Watts electical)
a deccent motor is round about 80% efficient (some a little lower, some a little better)
so that'd be 4100 Watts if that motor was halfway decent ( 5.5 metric horses)
it's got less than four..

that's what? noone knows for sure.. just say about 2800 Watts to get an estimate...
just over 50% efficient!
Rest is converted to heat and fry the motor (in a few minutes)
You again bring up RC crap!
that motor is MUCH MUCH MUCH worse (in performance) than the one we talked about earlier..

Anyways.. good Luck Ben, honestly!
I'm out

'sid
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Old 05-02-2016, 09:09 AM
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Okay... Didn't realize it was that terrible... Just came across it and noticed the hp rating. I casually posted the link on here to get everybody's opinion... Now I have your opinion and am not going to buy it. Thank you for your input.


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  #24  
Old 05-02-2016, 02:40 PM
JokerBen321 JokerBen321 is offline
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I just saw the motor : ME0909 . It seems insane!!

http://www.electricmotorsport.com/me...2-8-hp-pk.html

Is it worth the extra money?
  #25  
Old 05-02-2016, 04:57 PM
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First..
yes it's THAT bad.. and you could've seen that it is yourself if you finally stopped lurking for hp ratings and just used some very basic math (Volts* Amps = Watts[electric]) times efficiency (should be around 80% .. V*A*0.8 ~= Watts[mechanical]) to get the ideal mechanical power again in Watts.
(it's the first equation in the linked post )

things like that are important to make a wise decision, that's why I asked you to forget about hp ratings in the first place.

Aaaanywhoo...
The ME0909 has a good standing amongst DIY EV builders, so I think it's generally something worth considering if it's in the price and power range you need.
I can't download the Datasheet (since I refuse to register at that site)
wich kinda is important as well..
since the website's description is again fishy to absurd

I can't imagine it's as bad as they announce it to be.
4hp rating (uhhh come on fellows.. stop using crap like that!!) (2942 Watts about'ish I'd say... IF that's metric hp)

Now, at the same "label" (i.e. continous) it say's 48V and 100Amps... 4800 Watts electric,
that's only 61% efficient...

I can't imagine that's it's sweet spot at all,
but to know for sure, you should take a look at the performance pdf linked on that site.

Personally I'd stay away from anything that's less than 75% efficient (which is the lower end of modern PMDC motors efficiency)

frankly, since you'll likely overshoot the motor at one point (you or some friend of yours test-driving it) be warned:
a permanent magnet DC motor can be rendered useless in very short order..

Everything bit of power that is not converted to mechanical forward momentum is converted to heat..
magnets are very sensible to heat, and if "cooked" for too long or too hot they lose magnetic strength very quickly
Say you buy a 5kW PMDC motor like that.. max 100Amps or 300 for 30 secs..
you install a slightly bad ratio just to have an extra theoretical mph on your speedometer...
and your buddy floors it uphill for a minute and a half
then, when he finally comes back moaning about the low power of the kart.. that motor isn't able to produce more than maybe 800Watts of mechanical power anymore (since the magnets are already deep fried into uselessness)

I don't say it will happen, but it surely CAN happen!
Motors even in that pricerange are to be handled with care and according to their capabilities.

But check the spec sheet.. see what it's efficiency really is,
and if you cannot trust yourself or your friends enough to guarantee you will never apply more than 100Amps for more than 30 seconds (usually per 15mins of driving time)
then.. DO NOT BUY a PMDC motor at all..
find a series wound motor. Yes; you can kill them too.. but not nearly as easily

'sid

PS and yet.. you still search for hp labeled motors...
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  #26  
Old 05-02-2016, 05:58 PM
JokerBen321 JokerBen321 is offline
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Thanks! No, I didn't search for a Hp label, I searched "super fast electric go karts" and all of them said they used an "etek" motor... A few minutes later I found what seems to be the cheapest model which was the "ME0909"... It was a bit out of my price range, but if it was off the charts amazing I would have been willing to stretch, but from what you are saying, it isn't efficient and might burn up... Although, I could use an amp meter and just keep an eye on that... Not sure, I'll definitely keep that motor in mind. If these series wound motors are more resilient than PMDC's, what is the trade off? Price? Performance? Because I can't guarantee my buddy and I won't be babying these components all the time and if something that expensive breaks, that would be catastrophic...

Anyways, thanks for replying.
Ben

PS Should I venture off into brushless motors?


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  #27  
Old 05-02-2016, 06:19 PM
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trade off.. weight.. they're hefty bastards because of the stator coils..
price.. not really a good set of strong neodymium magnets are more expensive than copper...
soooo... in theory the prices should be equivalent.
Performance? nope not even slightly...
in fact a series wound motor should be able to outperform a PMDC easily torquewise.
One drawback apart from weight though.. they draw a bit more currents (since they need additional power to create the magnetic field for the rotor to grab on)
but after all that's almost negligible.

Brushless... if you say turnigy, I will slap you
No honestly, a brushless motor can be nice.. but typically they are runners not turners
Means the can produce rpms much better than they can produce torque...
you need the latter.

For a full size car on highway speeds.. a brushless motor is a good choice;
for a go kart.. I wouldn't say so, can be done of course...
but I'm not sure it's the easiest way at all

'sid

PS check the prices on brushless motors in that power and torque rating..
the one I remember from on top of my head was around 750 € (and asks for a 500 € controller) but that was a hair more powerfull than what you're looking at
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Old 05-02-2016, 06:33 PM
JokerBen321 JokerBen321 is offline
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Oh wow. Thanks for the info... And no I won't say Turnigy! Haha, I learned my lesson with them.... I will check out some wound motors... And goodness that brushless motor is expensive, I will have to look around to find something in my <$300 price range..... Yikes.


Ben


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  #29  
Old 05-02-2016, 07:28 PM
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yeah it was.. it also was ~20kW IIRC.. soo as I said.. a hair more powerfull than what you'll need

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  #30  
Old 05-02-2016, 07:32 PM
JokerBen321 JokerBen321 is offline
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Lol. Just a tad. Hopefully I'll be able to find one in the 2-5kw range in my budget.. 😬😬😬


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Old 05-02-2016, 08:00 PM
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how's that:
http://www.goldenmotor.com/frame-bldcmotor.htm

HPM3000B

(the 3kW 48V version is 260 and another 260 for a matching controller)
maximum efficiency just above 90% (awesome value!) at which it produces more than 4kW power OUT!
not bad at all!
the 72V version is even better than that (but you need a different set of batteries, whcih will add to the costs I assume)
if you can the liquid cooled version might be a good idea...

Anyways 520 for a set isn't too bad especially not if that motor holds what the spec sheets they provided promised.

'sid

Jeez.. look at what their 20kW costs
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  #32  
Old 05-03-2016, 06:17 AM
JokerBen321 JokerBen321 is offline
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Awesome thanks so much. I will definitely consider that, and right now that is my #1. A bit steep for both the motor and controller, but seems crazy good. Maybe I will check if there are any deals on other websites that sell it.


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---------- Post added at 08:17 AM ---------- Previous post was at 08:06 AM ----------

I took a look over that motor, what type of gear would I put on it? The rotor looks weird...


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Old 05-03-2016, 07:09 AM
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the shaft is a 20mm straight 5mm keyed shaft.. no problem..
depicted on the liquid cooled version is an optional internally splined shaft,
nothing weird either.. just to fit some golf cart gearboxes

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  #34  
Old 05-03-2016, 07:12 AM
JokerBen321 JokerBen321 is offline
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Okay yeah, I guess I saw the liquid cooled one and it looked weird.


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---------- Post added at 09:12 AM ---------- Previous post was at 09:11 AM ----------

Since this is a higher powered motor, do I need a thicker type of gear/chain?
  #35  
Old 05-03-2016, 11:56 AM
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you should be fine with #40 chain (NOT #41!!) 420 is also okay... 428 would be ideal IMHO,
but that could be harder to find (that'd be motorcycle chain) at least in sprocketsizes you can use on a go kart.

So back to #40.. tractor steel sprockets should hold up nicely
(chain .. just buy a quality product, not the cheapest)
Aluminium sprockets if they're exclusively for #40 (not the #40/#41 sprockets you see most of the time; those are narrower and might or might not hold up to the torque)

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  #36  
Old 05-03-2016, 12:42 PM
JokerBen321 JokerBen321 is offline
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Alright. I have never purchased gears or chain before so pardon my lack of knowledge... So #40 chain? And then I will deal with gear ratios and stuff later down the road when I actually get the chassis... Maybe there is a spur gear already on there I might have to match...


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Old 05-04-2016, 08:39 AM
JokerBen321 JokerBen321 is offline
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http://m.ebay.com/itm/161241114632

I found some (what seems to be nice) 428 chain on eBay... So this is the stuff you were talking about? It seems to be stuff you use on ATV's which would be great for my go kart.


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Old 05-04-2016, 11:46 AM
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https://www.gokartsupply.com/sprocket.htm

This seems to be a pretty good website as far as parts... I was looking through there gear/sprocket selection (I think I linked it properly, not sure if it is the right page sorry) and I only saw 3/4in and 5/8in "jack shaft" sprockets (which I assume are the ones that go on the motor) and the "jack shaft" on the golden motor BLDC motor is 20mm ~13/16in... (3/4in ~19mm) I assume I cannot buy those because 1mm is rather significant correct?

I will most likely use that website for the bigger sprocket and sprocket hub that will go on the axel (just have to wait to get the actual kart so I know what size axel it is)...

I played around with the gear ratio and speed calculator. I know it isn't accurate because it doesn't factor the unique weight or drag of your kart, but it was a good ballpark... Will play with it more when I have a better idea of what gears I will get.

I started looking into tires and stuff, was looking at the "Turf" tires... Just wondering what size I should get..

http://www.gokartsupply.com/tires.htm

Here is a link to the page, is there another type of tire I should consider? I just want a pretty inexpensive tire that is going to be relatively easy to mount to some rims and will get pretty decent grip on road. (I may do some off-road stuff in my back yard but I think for the most part I'll stick to asphault) My preference would be to get a set of 4 tires mounted on rims for under $50 but I guess that's not really reasonable so maybe $75...

I went for the turf style because I figured if I went for the slicks they might get more grip on road and I sort of want to drift/peel out if possible. Also, the slicks looked more expensive. Y'all know way more than me about this so please give your input if my thinking is wrong!!!!!!!

Ben

Last edited by JokerBen321; 05-04-2016 at 11:47 AM. Reason: Forgot to put link for tires!!!!
  #39  
Old 05-05-2016, 10:27 AM
JokerBen321 JokerBen321 is offline
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Alright, so I have looked into some more motors... I am now leaning towards the ME0201014201 brushless motor. ( http://www.evdrives.com/product_p/mot-me4201.htm ). I know it is a PM but I will instal an amp meter and watch the amps... I live in Florida so no hills, and I can't imagine my relatively light weight kart will pull that much... I have looked at kellycontrollers.com and wondering if this controller would work:

http://kellycontroller.com/kls6030s2...er-p-1341.html

I didn't go for the 300A one because it only does 300 amps for 10 seconds, and the motor peaks @300 for "1 minute"... Also, it can't hurt to have a little buffer of 50 amps... This is definitely a more expensive route, but I think with this motor peaking at around 14kw with a high efficiency if going to be ridiculous for my little 100kg go kart. This is going to be around $600 for the motor and ESC which is a bit much but I think it is going to be worth it... My second option if the golden motor 3kw BLDC motor ( goldenmotor.com ). It peaks at 6kw which is nice but 14kw is a crazy amount more for just $100 more....

So if anyone has any info regarding those motor setups please let me know!! I will need help with the wiring of the Kelly controller... Looking to buy a cheap little throttle controller ( which I would connect to the esc) and connect the throttle cable from the gas pedal, to avoid spending a fortune on electric throttles. https://electricscooterparts.com/throttles48volt.html
I would need to know how to wire the 3 throttle controlling wires to the esc... So if someone has a wiring diagram for that specific ESC please let me know!!!!!

Ben
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Old 05-07-2016, 01:46 PM
JokerBen321 JokerBen321 is offline
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What are those yellow caps on the shafts of almost every Motenergy Motor? Are they adapters to fit some sprockets or are they just there for shipping reasons?
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