[ruckus]

I think the racers are all over the Hellwig brushes. But racers tend to keep tech that gives them the 'edge' a secret.

I think the word is out.

The fact that Netgain switched over means they are undoubtedly better. The real-world gains have been tested and found to be somewhere around 12% better in terms of wh/mi. That also means 12% less heat which is my interest. 250F x .88 = 220F. Ahhhh, now that is better. Ok, now get that blower on there...

[somanywelps]

Do these work on kostovs?

[major]

Originally Posted by ruckus

The real-world gains have been tested and found to be somewhere around 12% better in terms of wh/mi. That also means 12% less heat which is my interest. 250F x .88 = 220F.

Hi ruck,

I, in no way, want to enter into a debate about brushes. However I have to point out that your statements which are quoted above are ridiculous. There is no way that 12% improvement in vehicle energy consumption could be attributable solely to a change in brushes. That amounts about 1 to 2 kW savings for an average EVcar in normal type driving. Just isn't feasible.

And then you must realize that temperature does not equal heat or power. A difference of a couple of kilowatts on the comm and brushes would cause a lot greater temperature differential than 30ºF. Your equation makes no sense whatsoever.

Regards,

major

[GizmoEV]

Originally Posted by major

There is no way that 12% improvement in vehicle energy consumption could be attributable solely to a change in brushes. That amounts about 1 to 2 kW savings for an average EVcar in normal type driving. Just isn't feasible.

While it is one data point you might want to see what Tim Catellier (http://evz3.blogspot.com/) found with a brush change. The one thing I question is that it came with a motor change too. The first Warp 9 had the old brush and the replacement had the new brush so I don't know if there were other factors influencing the results.

The brush tests done on EVTV weren't exactly scientific because the power output of the motor used wasn't kept constant. It was just left to free spin. Ironic as it may sound, when I drive my Gizmo full throttle, the faster it goes the lower the power use. This may have to do with the way the Sevcon SepEx controller is working but that is what I see. The faster spinning motor in the EVTV tests naturally lowered the current draw.

There is no question that the design and material make a difference. How much difference is the question. I wish I had a full size EV where I could test it my self. I would only change the brushes and note the difference.

[LithiumaniacsEVRacing]

I have new brush holders and the red top brushes for my Warp 11" motors, I was going to wait to install because I am so behind, but after reading these posts I just might install them before racing.

[LithiumaniacsEVRacing]

Originally Posted by LithiumaniacsEVRacing

I have new brush holders and the red top brushes for my Warp 11" motors, I was going to wait to install because I am so behind, but after reading these posts I just might install them before racing.

I would like to add, my brush holder kit comes with a set of “Power Tabs” these will eliminate the internal interconnections, power connection studs etc. and bring out a tab that is bolted directly to each of the brush holders. The “Power Tab” will protrude out from each of the “windows” in the end bell of each of my Warp 11’s. The power connection studs for the field coils will remain the same.

[GizmoEV]

Originally Posted by LithiumaniacsEVRacing

I would like to add, my brush holder kit comes with a set of “Power Tabs” these will eliminate the internal interconnections, power connection studs etc. and bring out a tab that is bolted directly to each of the brush holders. The “Power Tab” will protrude out from each of the “windows” in the end bell of each of my Warp 11’s. The power connection studs for the field coils will remain the same.

So does that mean you have to connect externally to each set of brushes so you have to make your own jumper between the pairs of brush sets?

[onegreenev]

Yes, That is exactly correct. But what it does is allow a fat connection instead of the typical skinny internal one. It allows for much better flow of those electrons. I love the idea. I added crossover cables to my Kostov but they are still internal but will carry more electrons with less resistance.

With the power Ron's pumping it is very important.

[ruckus]

Is that the Hellwig brush holder or a home brew? source? cost?

Major, I agree with your skepticism. The only way to find out is to test them. I will do this. I have taken temperature readings using an infrared thermometer driving a specific speed and distance. I will change the brushes, repeat the drive, and record the temperature.

Any drop in temperature is an increase in efficiency because inefficiency IS the source of the heat.

If a motor is using 300 watts to drive along and the motor is 85% efficient that is 45 watts going to heat. Raise that to 89% and now only 33 watts are heat. The motor efficiency changed 4% but the heat changed 27%.

My only test parameters are heat and ability to handle amps without the 'kxkxkxk' sound. Right now the heat on long drives is 250F and the max amps are 700. Not real impressive.

[major]

Originally Posted by GizmoEV

While it is one data point you might want to see what Tim Catellier (http://evz3.blogspot.com/) found with a brush change. The one thing I question is that it came with a motor change too. The first Warp 9 had the old brush and the replacement had the new brush so I don't know if there were other factors influencing the results.

Of course there were other factors. Tim does a nice job relating his experience. But that was far from a controlled test from which any valid conclusion can be drawn and the amount of power difference, again, is much greater than could possibly be attributable to brushes alone.

The brush tests done on EVTV weren't exactly scientific because the power output of the motor used wasn't kept constant. It was just left to free spin.

Unfortunately I am not privileged to have a decent internet access to make it possible for me to view EVTV. But if you infer a no-load test by "free spin", then I don't see how any valid conclusion could be drawn.

Ironic as it may sound, when I drive my Gizmo full throttle, the faster it goes the lower the power use. This may have to do with the way the Sevcon SepEx controller is working but that is what I see. The faster spinning motor in the EVTV tests naturally lowered the current draw.

Yes, of course a series (or SepEx controlled) motor draws less current (and therefore less power) as it speeds up. At a fixed voltage, the RPM decreases with load and vice versa. In your Gizmo, you see lower power use as the speed increases because the acceleration decreases. In a strictly controlled test, the higher speed would require more power in equilibrium conditions.

There is no question that the {brush} design and material make a difference.

I don't disagree. But it is unreasonable to attribute some of these "test results" solely to the brushes.

major