Novak HV4400 and 7XL BL Sensored System... - Page 7 - RC-Monster Forums

crazyjr · 04.23.2006, 06:53 PM

Thanks for the replies, I look foreward to your research. Can you rewind a hv to a higher wind? I have a wierd idea that if i could get somebody to rewind it, it would be more dependable and run better

GriffinRU · 04.23.2006, 09:46 PM

Quote:

Originally Posted by crazyjr

Thanks for the replies, I look foreward to your research. Can you rewind a hv to a higher wind? I have a wierd idea that if i could get somebody to rewind it, it would be more dependable and run better

I do not see why not, but you won't get more power from it. But can help in selecting gears.

Artur

crazyjr · 04.23.2006, 09:56 PM

I was thinking about lowering the kv of the motor. I'm new to brushless, though i've been reading about them for years. I've heard all the arguments about the HV reliability issues and have come to one conclusion, the kv is too high and stresses the esc when it maxxes out, the timing change doesn't help either. So i want to try a few turns higher and move the torque curve a little lower where it might be more useable and increase reliability.

Does anybody know how manny turns a 4400 is?

GriffinRU · 06:59 PM

Ok, I run it for 8-10 minutes and then ESC thermal :)
6XL is a serious motor (doesn't even need heatsink), but it was grass and second gear. Torque was great, maximum speed can be better. Overall I think e-maxx would be a rocket with sensored 9-10L. I will try to measure current draw later.

Artur

P.S. Batteries were almost drained as well, 300mah left from 4100+mah.
Need to work on better cooling...

crazyjr · 04.26.2006, 06:22 PM

cool i figured the 6XL would be too much, think a 9 or 10 XL would be a better setup

Serum · 04.27.2006, 02:03 AM

A 10L would be great, a friend of mine had one on his savage and was able to hit the 45 mph on 15 cells.

GriffinRU · 05.01.2006, 06:47 PM

Mods to make ESC run Cooler...
Remove silkscreen from power lines on PCB and upgrade with solid copper wire.
3 Runs heat is not an issue but differentials are gone. Front differential - main gear broke, rear diff. satellites gear broke (Milling the rest of aluminum housing :) ). Looking forward for 1/8 diffs bulkheads conversion...

Artur

MetalMan · 05.01.2006, 10:34 PM

Why didn't Novak do that?

05.02.2006, 06:52 AM

good question there is a lot of things novak could do to get their products better but the dont.

GriffinRU · 05.02.2006, 07:20 AM

Quote:

Originally Posted by MetalMan

Why didn't Novak do that?

Cost would be always the main, then specs and goals. On paper ESC rated at 375W, which is safe with current setup, but there is room for improvement and it is always nice to offer warranty when you have good setup.

When I attached 1200W motor and increase load a little bit, now with given internal resistance of only 2 FET's per phase, heat transfer and dissipation should be addressed. While current capabilities are sufficient, internal resistance is somewhat high, and in stock configuration (taking into consideration de-rating factors) is good for 30-35A continuous without overheating, which is about ~450W @ 12 cells. Adding extra copper increases thermal mass and improves conductivity on PCB, but adds weight.

So in stock configuration if you keep current under 30-35A (Average current) then you should be fine. This can be accomplished by installing high turn motor and achieving the same powers with voltage rather then current.

Meanwhile I will be exploring possibilities of high cell count in stock form and possible mods.

Artur

crazyjr · 05.05.2006, 01:57 AM

Are you going to offer that service for a price? I'd like to have it done but not sure i could do it.

GriffinRU · 05.05.2006, 01:05 PM

Quote:

Originally Posted by crazyjr

Are you going to offer that service for a price? I'd like to have it done but not sure i could do it.

Which motor you would like to use and how many cells?

Artur

crazyjr · 05.05.2006, 11:11 PM

I was thinking about a 7XL and no more than 16 cells or 5s lipo, anything more would be ridiculas. Before i do this i want to see if the HV is any competition for the nitro's around here as a new track is opening soon, If i get blitzed i will be talking to you.

BrianG · 05.05.2006, 11:55 PM

Quote:

Originally Posted by GriffinRU

Mods to make ESC run Cooler...
Remove silkscreen from power lines on PCB and upgrade with solid copper wire...

That's a pretty good idea by adding solder and wire to the traces - gives the trace a bit more "meat".

To increase the current capability of the ESC in general, what about simply adding a couple more FETs per phase? Those TO-220 style FET cases make it pretty easy compared to the surface-mount IC types. You'd probably have to add a PCB extension then use a different case - it would add a bit more weight but worth it IMO. From the pic, it looks like the source and drain leads are directly paralleled on each phase. From there, you'd have to see if the gates are directly paralleled, or if there is a resistor. The end result probably wouldn't be pretty, but you'd have roughly double the current capability and would heat up less due to the lower total "on" resistance. Just an idea...

GriffinRU · 05.06.2006, 12:06 AM

Quote:

Originally Posted by crazyjr

I was thinking about a 7XL and no more than 16 cells or 5s lipo, anything more would be ridiculas. Before i do this i want to see if the HV is any competition for the nitro's around here as a new track is opening soon, If i get blitzed i will be talking to you.

Ok.

Just keep in mind, hv with feigao motor has different performance then stock HV-Maxx combo. It would be fair to say compare 7XL performance on 16 cells with tremendous amounts of torque vs. Nitro's.

Amount of starting torque, based on motor type of simular size (power):
Brushed - up to 1000%
Brushless sensored - 250-300% (up to 500%)
Brushless sensoreless - 20-35% (less then 50%)

Artur