RC-Monster Forums - View Single Post - Novak's Nitro to Brushless Conversion Kits

NovakTwo · 01.24.2008, 05:57 PM

Bob Novak comments (from another Forum):

First off I have to say that Novak Electronics is happy to join all you guys out there that think that 1/8 scale Electric Off Road and possible 1/8 On Road racing is the thing of the future. We got into this about two and half years ago converting 1/8 scale nitro buggies to electric as an extremely reliable test bed for our HV Systems. They just ran and ran with very little maintenance. As time went on and more and more racers started doing their own conversions, and not seeing any of the car manufacturers coming out with a purpose built 1/8 electric buggy we decided to get into the conversion business. Our goal was to offer an inexpensive kit, easy to install with very little work or tools, and as good (or better) performance than the existing nitro buggies.

First off a 2 cell 8000mah Lipo should run the same as a 4 cell 4000 mah Lipo. Both have the same amount of energy in them and they both weigh the same. The difference is that the efficiency of a high voltage system is slightly better. Well then why don't we go to a 50 cell Lipo and realy cut down tha losses. It is true that higher voltage gives you more efficiency but then you run into charging and safety issues.

Our testing so far has shown that the electric motor brakes work very well and seem to be preferred by our test drivers. The one thing that electric brakes do is add run time as braking recharges the batteries. This was noticed when mechanical brakes were added and one to two minutes of run time was lost. It is true that mechanical brakes let the motor and speed control run cooler but with proper cooling, this is not a problem. The other factor with mechanical brakes is that it adds almost five ounces of extra weight and about 20% of that is unwanted rotational weight. Run times on our HV System were in the nine to sixteen minutes with a 4s 4000 mah Lipoly battery with various motor winds. This is two to nine minutes longer than a nitro powered buggy.

We found out that the 4.5 turn was almost too much power for our Expert (and I mean Expert) driver and the 6.5 was at, or a little faster, per lap than the nitro version with a $500 Team motor. We also tested a milder wind (7.5 turn) that will be good for beginner drivers and it was only a tenth of a second per lap slower, but very drivable. We also tested a 5.5 turn motor which is just a tad slower than the Neu 1512/1.5 motor which, by the way, is a very good motor. The 5.5 was faster than the 6.5 but run time came down a bit and it was easier to drive than the 4.5T. The choice of motor wind will come down to track size and length of race. Do I smell quick change battery setups?

Our test results on a prop between the Neu and 5.5 HV motors are as follows. This test was done at various voltages with the same propeller:

At 8 volts the Neu turned the prop at 25200 RPM at 44 amps and the HV 5.5 turned the same prop at 23500 RPM at 35 amps. This gives a loaded Kv of 3150 for the Neu and 2938 for the Novak.

Hope this answers most of the questions that you all had. If not ask again and I will try to answer them.
Bob Novak

	(#3)
NovakTwo Senior Strategist Offline Posts: 383 Join Date: May 2007	01.24.2008, 05:57 PM Bob Novak comments (from another Forum): First off I have to say that Novak Electronics is happy to join all you guys out there that think that 1/8 scale Electric Off Road and possible 1/8 On Road racing is the thing of the future. We got into this about two and half years ago converting 1/8 scale nitro buggies to electric as an extremely reliable test bed for our HV Systems. They just ran and ran with very little maintenance. As time went on and more and more racers started doing their own conversions, and not seeing any of the car manufacturers coming out with a purpose built 1/8 electric buggy we decided to get into the conversion business. Our goal was to offer an inexpensive kit, easy to install with very little work or tools, and as good (or better) performance than the existing nitro buggies. First off a 2 cell 8000mah Lipo should run the same as a 4 cell 4000 mah Lipo. Both have the same amount of energy in them and they both weigh the same. The difference is that the efficiency of a high voltage system is slightly better. Well then why don't we go to a 50 cell Lipo and realy cut down tha losses. It is true that higher voltage gives you more efficiency but then you run into charging and safety issues. Our testing so far has shown that the electric motor brakes work very well and seem to be preferred by our test drivers. The one thing that electric brakes do is add run time as braking recharges the batteries. This was noticed when mechanical brakes were added and one to two minutes of run time was lost. It is true that mechanical brakes let the motor and speed control run cooler but with proper cooling, this is not a problem. The other factor with mechanical brakes is that it adds almost five ounces of extra weight and about 20% of that is unwanted rotational weight. Run times on our HV System were in the nine to sixteen minutes with a 4s 4000 mah Lipoly battery with various motor winds. This is two to nine minutes longer than a nitro powered buggy. We found out that the 4.5 turn was almost too much power for our Expert (and I mean Expert) driver and the 6.5 was at, or a little faster, per lap than the nitro version with a $500 Team motor. We also tested a milder wind (7.5 turn) that will be good for beginner drivers and it was only a tenth of a second per lap slower, but very drivable. We also tested a 5.5 turn motor which is just a tad slower than the Neu 1512/1.5 motor which, by the way, is a very good motor. The 5.5 was faster than the 6.5 but run time came down a bit and it was easier to drive than the 4.5T. The choice of motor wind will come down to track size and length of race. Do I smell quick change battery setups? Our test results on a prop between the Neu and 5.5 HV motors are as follows. This test was done at various voltages with the same propeller: At 8 volts the Neu turned the prop at 25200 RPM at 44 amps and the HV 5.5 turned the same prop at 23500 RPM at 35 amps. This gives a loaded Kv of 3150 for the Neu and 2938 for the Novak. Hope this answers most of the questions that you all had. If not ask again and I will try to answer them. Bob Novak Novak Electronics, Inc.