Programmable Controllers and limiting current

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Wardon57
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Joined: 10/09/2008
Points: 9

Hello,

Hope you guys can help me. I will start by telling you what I plan on doing and then you can tell me if I am thinking correctly.

I have a Schwinn Stealth scooter, with five 21ah batteries (60 v) all with Powercheqs, origianly I had a Yi-Yun YK42-4 controller this worked fine no overheating isues all was normal. Well I was towing another person behind the scooter ( yeah I know bad idea) and burned up the motor at this time the controller also went. I bought a new motor and a new controller this time I went with a ZY-KK70 fron Tnc Scooters well now my motor is overheating due to the controller allowing more than 180 amps to flow through the motor (checked with Pak Trakr) so what I was thinking was replace the current controller with a kelly KDS60200 this controller should be programmable and alow me to limit current. So my question is, if I limit current with this controller to say 80 amps will this take care of my overheating problem? Or am I missing somthing about the way controllers work?

Thanks,

http://www.tncscooters.com/YK42-4.php

http://www.tncscooters.com/ZY-KK70.php

http://www.kellycontroller.com/mot/Small-DC-Motor-Controller.html

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Dave-s
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Joined: 03/10/2008
Points: 58
Re: Programmable Controllers and limiting current

The KK controller looks like it does have a current limit. It says: 60 - 100 Amps.
If your motor it heating up without you going up hills or putting too much stress on the motor then there is something wrong with the scooter.
you should check if there is any friction that is burdening your motor, and causing it to heat up. Or maybe your new motor is rated for a lower voltage/power rating?
There is no real reason for a motor to pull so much current from the batteries on the flats.

antiscab
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Joined: 07/07/2007
Points: 1595
Re: Programmable Controllers and limiting current

is that 180A on the battery side continuous?
or the peak you see during acceleration?

if its the peak, what is the continuous amps?

180A on a 60v pack would be a rocket, even after voltage sag.

Matt

__________________

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst replacement TC Charger
conversion
Spent so far: $5800 + $7000 + $1720 + $960 + $320 + $720 + $140 + $600
Cost to do it again: $2500 + $5600 + $1720 + $960 + $320 + $720 + $140 + $600
Cost for a Petrol bike:$6000 + + $1440 + $6000 + $800 + $1400 + $3200 servicing
Total spent: $17260
Total to do again: $12560
Total to have used a petrol bike: $18840
Total distance travelled so far: 79'120km

chas_stevenson
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Joined: 12/06/2006
Points: 1309
Re: Programmable Controllers and limiting current

You have the right idea. The controller is where you should limit the current. The real question is "What is the motor rated for?" If the motor is rated for 40 amps and you run it at 80 amps it will still over heat. Most DC brushed motors can handle 3 times their rating for a short time, 1 to 2 minutes. But when you run them at to high a current for long periods they will smoke. When you were pulling someone you cause high current to flow for an extended period of time which of course cause the smoke. I am sure the motor saw the same high current many time before this event but only for short periods of time, like during hill climbing or acceleration.

If you limit the current to about 2 times the motor rating you should be OK as long as you remember to use less throttle when towing someone.

Grandpa Chas S.

Wardon57
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Joined: 10/09/2008
Points: 9
Re: Programmable Controllers and limiting current

180A is durring accel. I don't remember what is is on the flats I currently run it at 48v (with no overheating) so it's been a while since it was at 60v.

The motor is rated for 40A, but at 36v. Though like I said everything was normal and cool running at 60v until the new larger controler. The kk is out of the question because it was not designed for 60v and we have burned up 3 of them by turning on the scooters right after pulling them from the chargers.

What I need to know is if the kelly programable controler will limit the current to what I set it at (40% fo a 200A controler) or will it still allow the motor to pull that massive amount of current.

I will never tow someone again I learned my lesson on that one. I am trying to build one of them into a tow truck style with low gearing so when one breaks down we can tow it home. I have had way to many wrecks due to tow straps getting caught in the front wheel.

Thanks Guys,

P.S. Sorry about spelling errors.

chas_stevenson
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Points: 1309
Re: Programmable Controllers and limiting current

From what I understand the Kelly controller is a very good unit and if you set the current to ??amps that is the maximum the motor will see. I like your tow truck idea. I have a trike that the motor runs through gears and I can tell you that in low gear you get lots more power with very little strain on the motor.

Grandpa Chas S.

Wardon57
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Joined: 10/09/2008
Points: 9
Re: Programmable Controllers and limiting current

Thanks for the info, after I get the new controller installed I will post some performance nnumbers and maybe a video or pics.

causalitist
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Joined: 03/11/2009
Points: 3
Re: Programmable Controllers and limiting current

just get a $4 MC33033 or sg3524 ... slap on 4 irfp4368 mosfets.. a 6 10,000uf capacitors across controller input.. and rurg5060 output diode... and thats that... you have a 400amp controller ...
then buy a allegro hall effect current sensor, slap the output of it to the current sense pins on this chip... and there you go.. 1-400 adjustable current limit.

im using 50amps only, but thats cuz im using 148 volts on my mountain bike...

but you want programmable? why? just turn a little trimpot and wala..
hall effect sensor... http://www.allegromicro.com/en/Products/Part_Numbers/0755/index.asp
it puts out 10mv/amp .. perfect for the 100mv current limit threshold on these chips.
http://www.irf.com/product-info/datasheets/data/irfp4368pbf.pdf
and there is is, 400amp 1-400amp adjustable current limit controller.

and dont be threatened by all the pins on these chips.. you dont really need most of them

antiscab
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Joined: 07/07/2007
Points: 1595
Re: Programmable Controllers and limiting current

causalitist wrote:

im using 50amps only, but thats cuz im using 148 volts on my mountain bike...

but you want programmable? why? just turn a little trimpot and wala..

im guessing that 50A is motor side amps?
6000w on a mountain bike would be a sight to see.

a programmable controller allows you to set independent battery and motor voltage and current limits
it also means the battery low voltage limit is a soft limit rather than hard (when the voltage sags below this cutoff on acceleration, the controller backs of battery side current until voltage is back above limit. a hard limit causes oscillation between 0 and throttle input).
these features are tricky to implement without involving a computer of some desription.

Matt

__________________

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst replacement TC Charger
conversion
Spent so far: $5800 + $7000 + $1720 + $960 + $320 + $720 + $140 + $600
Cost to do it again: $2500 + $5600 + $1720 + $960 + $320 + $720 + $140 + $600
Cost for a Petrol bike:$6000 + + $1440 + $6000 + $800 + $1400 + $3200 servicing
Total spent: $17260
Total to do again: $12560
Total to have used a petrol bike: $18840
Total distance travelled so far: 79'120km

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