# Controller for small brush DC.



## McRat (Jul 10, 2012)

This is low power motorcycle project - 

The "bicycle" ones I have aren't going to handle their advertised power.

So I need a controller that will handle 10HP at 48v for testing purposes.

It will only be used for testing the layout and handling.

What is good choice for this kind of application, that a newbie can handle. IE - something with specs and instructions. It must handle variable throttle, but no regeneration or reverse capability. I'm thinking Golf Cart, or Forklift, but there are no docs with them, and they are pretty expensive new.

Any ideas?


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## major (Apr 4, 2008)

McRat said:


> This is low power motorcycle project -
> 
> The "bicycle" ones I have aren't going to handle their advertised power.
> 
> ...


Hi Rat,

Look at a Curtis 1204 or 1205 or an Alltrax. Can often be found in good used condition, sometimes on eBay. Manuals usually on line. Been around for decades and still pretty good. 

Regards,

major


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## McRat (Jul 10, 2012)

Thanks! Will do.


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## McRat (Jul 10, 2012)

Ordered a Curtis 1204. What type of throttles do these run? Rheostat or something else?

REALLY dumb question. Does an DC ammeter reduce current flow a lot? It looks like you run it in parallel with a resistor. My A/C ones just clip around the wire, but my DC handheld ones only go to 1 amp.


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## Arlo (Dec 27, 2009)

McRat said:


> Ordered a Curtis 1204. What type of throttles do these run? Rheostat or something else?
> 
> REALLY dumb question. Does an DC ammeter reduce current flow a lot? It looks like you run it in parallel with a resistor. My A/C ones just clip around the wire, but my DC handheld ones only go to 1 amp.


 You can use a 5k Pot thats what I did. I found with some digging the 3rd wire form the Pot needs to be grounded and curtis does not show it in the manual.


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## Woodsmith (Jun 5, 2008)

McRat said:


> REALLY dumb question. Does an DC ammeter reduce current flow a lot? It looks like you run it in parallel with a resistor. My A/C ones just clip around the wire, but my DC handheld ones only go to 1 amp.


The ammeter will go inline between the pack and the controller, however, it cannot handle anymore then a few mA so you need a shunt resistor in parallel with it.

In reality the Shunt is in line and the Ammeter is just a volt meter reading the voltage dropped across it and showing it as amps on a suitably calibrated scale.

You should be able to buy an ammeter with matching shunt resistor to allow it to read the range you want.

On my tractor I installed a Cycle Analyst to show and record all the electrical data and that gave me my Amps. I think you would do well to consider one. ( I am going to get a second one and try to package it as a portable test instrument for myself to use.)

















I also wanted an analogue gauge on the tractor and bought a 600A ammeter. I put it in parallel to the Cycle Analyst's shunt and then fine tuned it with a small preset pot until it read the same as the digital display.









I also bought a couple of DC clip on ammeters to use for spot checking currents. One was 0-100A, the other 0-600A.


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## Yabert (Feb 7, 2010)

McRat said:


> Ordered a Curtis 1204.


I prefer a lot the Alltrax controllers: http://alltraxinc.com/Products_SPM.html


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## McRat (Jul 10, 2012)

The Curtis was $150 new on Ebay. Good price for experiments. It's not the final controller I'm going to use.

If I blow up an expensive controller or motor or battery learning, then my budget is shot. If I buy low power cheap stuff and it blows up, I'm OK. If I buy low power cheap stuff and it works, I resell it and buy better stuff.


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## Yabert (Feb 7, 2010)

150$ only.. Ummm! Good find! I understand your choice.
Enjoy it.


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## Arlo (Dec 27, 2009)

You can open up the curtis and add the mosfets they left out and make it more powefull! Mine was a 225 amp 50v model and I added 11 missing mosfets and gate resistors and now its a 500 amp model!


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