Increasing Speed

[David Merrill]

My old motor (36V) would run at 37 mph freewheeling - spinning in air. It finally broke and I have replaced it but the new controller only freewheels up to 26 mph. This is a little slower than I am accustomed to.

Is there a way to increase the speed? I want a few more miles per hour.


Regards,

David Merrill.

[johnbear]

I add a small battery in series with the 36v battery to increase top speed. A 4 cell nimh works well.

[David Merrill]

I add a small battery in series with the 36v battery to increase top speed. A 4 cell nimh works well.

Thanks.

How many volts and amps?

[OneEye]

4-cell NiMH would be nominally 4.8V.  You want to match the amp hours of the rest of your battery pack.  You can go slightly lower than the Ah of an SLA set if the current rating on the cells is high enough.  Otherwise, you need enough capacity so the 20A doesn't exceed the continuous "C" rating of your cells.

[David Merrill]

That does not compute for my charger system - which I want to keep simple.

Let's take a look at the controller for a minute:

http://www.onsemi.com/pub/Collateral/MC33035-D.PDF

My friend has a 3 hp motor that is no bigger than my Goldenmotor 36V motor. So it makes sense that the controller is what is regulating the speed.


Regards,

David Merrill.

[amhay]

What about increasing the limit of the Amp the controller can supply by buffing the shunt resistors bit, would that give more top end speed?

what about is to increase the voltage on the MOSFETs only?

[David Merrill]

Lower the value of Rs while increasing power?

That would increase the current through the motor.

There is a right angle bend in the power wires tied into the coil harness (attached). You have to loosen that up a bit first or the heat will connect the wires - melt the insulation.