new to this

[alim]

Do you still have any of
...the blades? (I guess you would call it, if they are motors that came off of lawn mowers)

Ya know, what ever originally attached to the motor shaft

Maybe you could just cut/grind off what ever you don't need, basically down to the arbor
...then have your guy weld one of your sprockets to that

Boom!

One custom made, removable sprocket.

FA, love that idea. Thanks!

 

[alim]

Frankly I'd even go so far and say get an appliance controller instead of an EV one:
http://www.ebay.com/itm/2000W-40A-1...d-Control-PWM-HHO-RC-Controller-/221842925195

it handles up to 40Amps and is even cheaper
that thing should blow... (I said it'll be wasted, right )
and once it does and you can be reasonably sure the motor is indeed drawing more than those 40 Amps.
'sid

So the idea is, get a cheap (lower rated) controller and see if it blows.

Is there any difference between these appliance controllers and the EV ones, besides all the bells and whistles like brake light, power locks, etc? When you said "that thing should blow" is there some reason why it would be more likely to blow?

 

[itsid]

several.. the brake"light" for example is just a side effect,
the IMPORTANT part is, that the controller shuts the motor off when the brake is engaged.
A second is undervoltage protection
(once a battery is below a certain point it cannot be recharged... thus undervoltage protection is crucial to keep your batteries alive)
Appliance controllers usually run off a PSU thus they don't care about battery protection.

Now that linked controller should blow is because of the assumed amperage draw of your motor..
(more than 40A) so a 40A controller will burn out eventually...
And it's just to verify the motor power you assumed.
(and because a real controller for that motor would cost around 100 bucks [for very good reason!])

'sid

 

[alim]

What kind of brake do you use in an electric kart? I haven't planned that part out yet

Just doing some reading and another difference would be the throttle. The appliance controller uses a potentiometer, but your typical foot-pedal electric go-kart throttle uses Hall effect sensors.

 

[itsid]

the same brake as you would on any other kart (belt, drum or disc, mechanical or hydraulic)
the sole difference is the pedal..
for an electric kart you want an additional momentary switch on the pedal to tell the controller you are actually trying to stop. (usually these are NC switches)

AGAIN: for a kart do NOT use appliance controllers.. never ever!
they do not have any security feature and will cause trouble
(at best to the batteries, at worst to someone's health)
Yes, the prices are tempting.. but just walk away!

throttle not really.. yes EV controllers use hall effect sensors instead of std potentiometers mostly,
but most allow for both, some older golf carts even REQUIRE potentiometer throttles to work predictably.. in essence they do the same thing
(some known voltage in, some regulated voltage signal out).

'sid

 

[Functional Artist]

It may be interesting to see how one of your motors works with a low cost controller, like this: (~$35.00)

https://www.ebay.com/itm/1000W-48-V...m=161881435758&_trksid=p2047675.c100752.m1982

It's for a 1,000W 48V motor & probably only ~20A (maybe a bit more)
but, it will at least let you do some testing & which should give you an idea of where your at.
(how much power the motor "actually" draws, how long the speed controller lasts etc.)

...or another option would be to try a used/referbished golf cart speed controller like this: ($170.00)

https://www.ebay.com/itm/P125M-5603...ash=item283b00c649:g:SFwAAOSw5n5ZiY86&vxp=mtr

 

[itsid]

It may be interesting to see how one of your motors works with a low cost controller, like this: (~$35.00)

https://www.ebay.com/itm/1000W-48-V...m=161881435758&_trksid=p2047675.c100752.m1982

It's for a 1,000W 48V motor & probably only ~20A (maybe a bit more)
but, it will at least let you do some testing & which should give you an idea of where your at.
(how much power the motor "actually" draws, how long the speed controller lasts etc.)

...or another option would be to try a used/referbished golf cart speed controller like this: ($170.00)

https://www.ebay.com/itm/P125M-5603...ash=item283b00c649:g:SFwAAOSw5n5ZiY86&vxp=mtr

that's exactly why I suggested buying the 7 dollar appliance controller (with 40 Amps)
TESTING...

28 dollars cheaper.. twice the testing capability
And.. it's a 24V motor... a 48V controller is just no match

'sid

 

[Functional Artist]

that's exactly why I suggested buying the 7 dollar appliance controller (with 40 Amps)
TESTING...

28 dollars cheaper.. twice the testing capability
And.. it's a 24V motor... a 48V controller is just no match

'sid

OK, I guess, I was confused when you said:

AGAIN: for a kart do NOT use appliance controllers.. never ever!
they do not have any security feature and will cause trouble
(at best to the batteries, at worst to someone's health)
Yes, the prices are tempting.. but just walk away!

So, you were talkin' about for bench TESTING... purposes only

...just tryin' to suggest alternative ideas

 

[alim]

TBH I'm a little less interested in testing and a little more interested in karting. I think i'll go with the cheapo EV controller, and if it blows I'll get the Kelly.

 

[itsid]

if you WERE interested.. it wouldn't have taken the best part of 6months to check back on that topic.

if you'd knew whta motor specs you are dealing with no testing would be required,
if you want karting it's QUICKER and CHEAPER to run a quick test first then DIRECTLY buy a matching controller for your motor and not try some cheap 'not really an alternative'-crap first.
since frankly that's exactly what testing means, just guaranteed NOT to work and way more expensive since the controller FA linked will NOT WORK at all (being 48V and such)..

but alright alright...as you please

'sid

PS I'll better stay away from this topic then

 

[alim]

Aww c'mon Sid, it ain't like that, I just said I was a "little" less interested in testing, and that's exactly what I meant

My thinking was this: why test using an appliance controller that as you say can NOT never ever be used for a cart? When I could try a controller that actually COULD be used for a cart? If the controller holds, I could use it. If it blows, I get the next size up that could actually be used for a cart. In this case, that next size up is the Kelly. But if there was a higher-power cheapo eBay EV controller I would definitely try that first, would be great to know the actual motor power. But with 24v the only choices are 350w, 500w, and the Kelly. Know what I mean?

 

[Functional Artist]

if you WERE interested.. it wouldn't have taken the best part of 6months to check back on that topic.

if you'd knew whta motor specs you are dealing with no testing would be required,
if you want karting it's QUICKER and CHEAPER to run a quick test first then DIRECTLY buy a matching controller for your motor and not try some cheap 'not really an alternative'-crap first.
since frankly that's exactly what testing means, just guaranteed NOT to work and way more expensive since the controller FA linked will NOT WORK at all (being 48V and such)..

but alright alright...as you please

'sid


PS I'll better stay away from this topic then

I understand the want/need for testing
...cause of the unknown motor specs

I try to look at things from several directions
..."there is more than one way to skin a cat"

From what we know, about these small motors or DC motors in general
...we can/should be able to make some "educated guesses" about a potentially compatible speed controller

I am still not completely understanding how/why your suggesting to use an appliance controller
...cause you could only "safely" do bench testing
...& potentially damage the batteries (if not careful)

What about "actual" load tests?
...which you could only do "on a kart"
...with the weight of the driver & some rolling resistance

That's why I suggested an inexpensive "actual" go kart style speed controller
...so, he could do some "real" tests
...& maybe even get to ride

Thomas Edison said, "No experiment is ever a failure, because now, we know FOR SURE that, that idea, will or will not work

 

[itsid]

Aww c'mon Sid, it ain't like that, I just said I was a "little" less interested in testing, and that's exactly what I meant

My thinking was this: why test using an appliance controller that as you say can NOT never ever be used for a cart? When I could try a controller that actually COULD be used for a cart? If the controller holds, I could use it. If it blows, I get the next size up that could actually be used for a cart. In this case, that next size up is the Kelly. But if there was a higher-power cheapo eBay EV controller I would definitely try that first, would be great to know the actual motor power. But with 24v the only choices are 350w, 500w, and the Kelly. Know what I mean?

You still do not understand, ..

IT COULD NOT work, in case your motor IS 2000 Watts (what we need to assume)
NO "cheap" EV controller is available (PERIOD!)
the 48V controller will never work (it has undervoltage protection low enough that you're unable to fire up your motor at all)
you WILL burn your motor up if you try to apply a voltage high enough for the 48V controller to even start powering the motor
(and you not only waaste 35bucks for the controller but also the entire motor if bad comes to worse)

IT WILL SIMPLY NOT WORK... it cannot work, you are wasting 35bucks at least (again, overvolt it and you can fry your motor as well)

Those cheap 300-500W controller do have the correct voltage, but they will fry as well since the motor (assumingly) draws four to five times the current,
the internals of such controller are not able to withstand that currentdraw and cook off in a matter of seconds.

IT WILL SIMPLY NOT WORK!!!

Now, all of that I said before and frankly I'm tired of repeating that over and over again.

IF the motor draws 40 Amps (which again is only an assumption as of now)
the ONLY viable controller is said Kelly (well apart from more expensive controllers in that voltage/amperage class)

it itself is not exactly cheap at first glance, and I understand that someone is reluctant to buy it if it's not needed...

And that is where that cheap 7buck appliance controller comes in.. seven bucks to know for sure...
yeah I know, 7 bucks wasted eventually, just to gain some knowledge.

but what can I say, I haven't said before? Nothing....
you cannot buy any controller that is not meant for 24V, that's a fact.
You MUST buy a controller that can handle the amperage the motor is trying to draw from the battery pack
(a value yet unknown but likely well above 20 Amps)
Sooo, is 40 enough or not? I don't know, you don't know and for sure FA doesn't know either as of yet.

One 7 dollar way to find out is all I could come up with,
since more sophisticated tools to find out are way more expensive than that.

And yes, that still remains a suggestion not a "do or die" advice..
my advice however is: DO NOT BUY a 48V controller (wasted money)
and DO NOT BUY a 500W controller either (more than just likely wasted money)

Now.. if you have a better idea, no problem,
but buying a 500W 48V controller or something is in fact a stupid waste of time and money.

'sid

 

[Functional Artist]

You still do not understand, ..

IT COULD NOT work, in case your motor IS 2000 Watts (what we need to assume)
NO "cheap" EV controller is available (PERIOD!)
the 48V controller will never work (it has undervoltage protection low enough that you're unable to fire up your motor at all)
you WILL burn your motor up if you try to apply a voltage high enough for the 48V controller to even start powering the motor
(and you not only waaste 35bucks for the controller but also the entire motor if bad comes to worse)

IT WILL SIMPLY NOT WORK... it cannot work, you are wasting 35bucks at least (again, overvolt it and you can fry your motor as well)

Those cheap 300-500W controller do have the correct voltage, but they will fry as well since the motor (assumingly) draws four to five times the current,
the internals of such controller are not able to withstand that currentdraw and cook off in a matter of seconds.

IT WILL SIMPLY NOT WORK!!!

Now, all of that I said before and frankly I'm tired of repeating that over and over again.

IF the motor draws 40 Amps (which again is only an assumption as of now)
the ONLY viable controller is said Kelly (well apart from more expensive controllers in that voltage/amperage class)

it itself is not exactly cheap at first glance, and I understand that someone is reluctant to buy it if it's not needed...

And that is where that cheap 7buck appliance controller comes in.. seven bucks to know for sure...
yeah I know, 7 bucks wasted eventually, just to gain some knowledge.

but what can I say, I haven't said before? Nothing....
you cannot buy any controller that is not meant for 24V, that's a fact.
You MUST buy a controller that can handle the amperage the motor is trying to draw from the battery pack
(a value yet unknown but likely well above 20 Amps)
Sooo, is 40 enough or not? I don't know, you don't know and for sure FA doesn't know either as of yet.

One 7 dollar way to find out is all I could come up with,
since more sophisticated tools to find out are way more expensive than that.

And yes, that still remains a suggestion not a "do or die" advice..
my advice however is: DO NOT BUY a 48V controller (wasted money)
and DO NOT BUY a 500W controller either (more than just likely wasted money)

Now.. if you have a better idea, no problem,
but buying a 500W 48V controller or something is in fact a stupid waste of time and money.

'sid

Why U mad bro?

Were just bouncing ideas around, discussing & learning ...as we go

The math doesn't seem to work out
...a 2,000W motor operated @ 24V should draw ~80A NOT 40A

But, I still don't understand your reasoning in this situation.

If the motor is 2,000W & only operated @ 24V it should draw ~83A (2,000W/24V = 83.33A)
...@ 36V it should draw ~55.55A
...& @ 48V it should draw ~41.66A

Remember
...if it's operated @ 24V it is only going produce ~2,000 RPM's (probably NOT much fun) while drawing that ~80A
...@ 36V it should produce ~2,500 RPM's while drawing ~55A
...& @ 48V it should produce ~3,000 RPM's while only drawing ~40A

Also, remember
...when more voltage is applied, less amperage is required (drawn by the motor)

I think that the "testing" Alim wants to do
...is to see if a motor off of an electric lawn mower will work on a go kart
...& produce enough power to "have some fun"

Your right, these motors may NOT function, for long @ 36V or 48V
but, IMHO & if Alim is "game" lets find out

 

[alim]

My bad, I didn't realize a 350w controller wouldn't work at all. I missed that somehow!

I'm not gonna do anything wacky like 48v

So that makes more sense to me now. The appliance controller is purely a bench test, if it blows we know I need the Kelly, if it doesn't blow... wait, what if it doesn't blow?

 

[itsid]

Why U mad bro?

Were just bouncing ideas around, discussing & learning ...as we go

The math doesn't seem to work out
...a 2,000W motor operated @ 24V should draw ~80A NOT 40A

But, I still don't understand your reasoning in this situation.

If the motor is 2,000W & only operated @ 24V it should draw ~83A (2,000W/24V = 83.33A)
...@ 36V it should draw ~55.55A
...& @ 48V it should draw ~41.66A

Remember
...if it's operated @ 24V it is only going produce ~2,000 RPM's (probably NOT much fun) while drawing that ~80A
...@ 36V it should produce ~2,500 RPM's while drawing ~55A
...& @ 48V it should produce ~3,000 RPM's while only drawing ~40A

Also, remember
...when more voltage is applied, less amperage is required (drawn by the motor)

I think that the "testing" Alim wants to do
...is to see if a motor off of an electric lawn mower will work on a go kart
...& produce enough power to "have some fun"

Your right, these motors may NOT function, for long @ 36V or 48V
but, IMHO & if Alim is "game" lets find out

I know that the appliance controller isn't up to par.. it doesn't need to,
it just needs to verify that we need the next bigger kelly with 100A
(or be fine with the smaller 50A one)
and a bigger appliance controller would add to the costs rather unnecessarily since the price difference in the two kellies is only 30 bucks (so it'd be cheaper to just buy the bigger one anyways)
since frankly I'm not sure that motor has 1900Watts at all maybe 60 bucks 50 amps do.. maybe 100A 90bucks is the way to go..*shrugs*

I'm mad because you are giving FALSE ADVICE..

since it's a lie that a motor would draw less amps on higher voltage!
motor windings do care about voltage, but they are not self regulating!

Yes a FIXED POWER motor would -in theory- draw less amps..
but there is no such thing as a fixed power motor, the only thing that can be fixed in place is maximum amperage draw.
(that's what limits the motor power given the voltage the windings are able to withstand)
sooooo.. 48Volts on a a 24V motor would still draw about the same currents (a little bit less thanks to heated coils... say 72Amps or so)

(with the sole difference that the motor coils will likely cook off their insulation due to the excessive heat and thus the motor will be TOAST!)

Your advice could potentially destroy alim's motor...
I personally do not think that this would be at any rate good or even fair advice here.

But alright, try it.. put 96V on your 48V motor
(double the voltage, right?) and see it glow....
it'll be a paperweight afterwards,
but that's essentially what you are saying is a good idea, no?

In fact don't... it's not worth it to prove me right on this one...

In any case.. 60/90bucks is not cheap.. 40 bucks thrown out the window is stupidly expensive,
wouldn't you agree?

'sid

 

[Functional Artist]

I know that the appliance controller isn't up to par.. it doesn't need to,
it just needs to verify that we need the next bigger kelly with 100A
(or be fine with the smaller 50A one)
and a bigger appliance controller would add to the costs rather unnecessarily since the price difference in the two kellies is only 30 bucks (so it'd be cheaper to just buy the bigger one anyways)
since frankly I'm not sure that motor has 1900Watts at all maybe 60 bucks 50 amps do.. maybe 100A 90bucks is the way to go..*shrugs*

I'm mad because you are giving FALSE ADVICE..

since it's a lie that a motor would draw less amps on higher voltage!
motor windings do care about voltage, but they are not self regulating!

Yes a FIXED POWER motor would -in theory- draw less amps..
but there is no such thing as a fixed power motor, the only thing that can be fixed in place is maximum amperage draw.
(that's what limits the motor power given the voltage the windings are able to withstand)
sooooo.. 48Volts on a a 24V motor would still draw about the same currents (a little bit less thanks to heated coils... say 72Amps or so)

(with the sole difference that the motor coils will likely cook off their insulation due to the excessive heat and thus the motor will be TOAST!)

Your advice could potentially destroy alim's motor...
I personally do not think that this would be at any rate good or even fair advice here.

But alright, try it.. put 96V on your 48V motor
(double the voltage, right?) and see it glow....
it'll be a paperweight afterwards,
but that's essentially what you are saying is a good idea, no?

In fact don't... it's not worth it to prove me right on this one...

In any case.. 60/90bucks is not cheap.. 40 bucks thrown out the window is stupidly expensive,
wouldn't you agree?

'sid

Wow!...just Wow!

I thought you were getting mad (frustrated with) Alim, not me

My Badd,

I am just trying to help, I am NOT trying to give FALSE ADVISE

Your the electric guy NOT me.

You know I have no formal, electrical education or training

I'm a certified/professional tow truck driver (my regular day job)

I am mostly self taught on everything else
...& learned almost everything I know (about electric motors on karts) from YOU!
...personal research
...& hands on testing/learning

* "FALSE ADVISE" & "it's a lie" are kinda strong words to imply that someone is mistaken. (don't you think?)

The amp value ratios that I mentioned are
...from personal testing (e-Lemon-aid drew ~15A avg. @ 24V but, only ~8A avg. @ 48V) http://www.diygokarts.com/vb/showthread.php?t=37442&page=2
...& from research, I thought that dividing watts by volts = amps (W/V=A)

* I still, do not understand how a bench test (without the "actual" load) will be helpful.

As you know, I have done some (lots) "bench" testing & "actual" testing on these small PMDC motors.

The motors I tested just barely registered an amp draw (~1A-3A) without a load
https://www.youtube.com/watch?v=1_9XMrJohm8

...but, drew substantially more (~30A) with the load of moving a kart & driver
https://www.youtube.com/watch?v=n1aysgJYGQ8&t=34s

 

[itsid]

Oh come on.. you have a lot of electric toys around, and frankly..
even without formal training you really know a thing or two about electric motors,
you are not just colormatching wires until it works...
you might know more than you are actually aware of (at worse)
you might not be aware of WHY you don't do this or that,
but you have a strong feeling you shouldn't, right?

So yeah I got mad at you
(as mad as you'd get with a family member if s/he tries to stop a circular saw with his/her bare hands, not as mad at you get at the junkie trying to pick pocket your wallet that is )

So yes, strong words... not to hurt you, but only to make perfectly sure,
alim's motor is not getting fried because of what I feel (knowing is a different page in this book tbh) is a sure deathsentence for his motor..

Remember, it's not my motor, it's not yours and even the risk of burning it because of OUR advice is nothing that should be taken lightly IMHO...
I think we not only should take care that nobody gets hurt because of what we tell people on this forum (although that's a higher priority!)
We should also at least try to keep all their engines, motors and karts in working condition.

So yeah, because I had a strong feeling this was going haywire
"oh well then I justbuy and fry a controller I don't need and the motor I have instead of testing first"
- that's what a previous post read for me -

I got a little nervous, and worded stronger than before..
just like one would garab their kid's arm stronger than usual to stop it from walking in front of the bus

If you took that personally, my apologies for that.

BTW:
I haven't said "no load" bench testing, have I?
I'd test w/o load first of course (to get some idea or baseline let's say)
but then I'd increase the loads until the controller get's too hot for my taste..
and then derive my further assumptions from that..
eventually I'd stress test (firmly mounted motor of course; that's obvious, isn't it?)
to see how hot the motor gets at near stalling speeds before the controller dies...
(I said it'll be wasted eventually)
and then make my final call based on what I've learned so far.
the hotter the motor gets the closer it is to it's maximum amperage.
stalling speed (high load), controller died the magic dragon death and the motor is still cool to the touch... 100Amp controller!
Sure an Amp meter would come in handy, but even just careful observation
of the temperatures of the motor controller, wires and batteries can tell you a lot
and it's totally free it only takes time and some precaution whilst testing.

I haven't gotten into any details yet AFAIR, there was no need yet (assuming testing is not going to happen anyways and such)

'sid

 

[alim]

you are not just colormatching wires until it works...'sid

lol!

 

[alim]

Ok guys, just bought one of these:

https://www.ebay.com/itm/121947043393

So the plan will be to bench test the motor and get a feel for whether it actually 100A+ as my voltage divider measurement says.

Stay tuned!