Once again Hong Nor (Jammin) CRT.5 brushless conversion

[tomik]

Hello, I'm Tomi from Finland and this is my first post on this forum.

After crawling for a bit over a year I decided to try something different... A brushless truggy :). I've had some electric and nitro rigs before, but this will be the first "high-speed" (don't know yet how fast this thing will go eventually) rig.

Here's the car (I bought it used from a friend): http://tomikulmala.smugmug.com/gallery/5419981_8fYsp/ . I'm going to use KD36-60-07L (3500kv) as motor, ZIPPY-K 4300mAh 2S1P 20-30C as battery and Castle Creations Sidewinder as ESC.

I've already ordered the motor and battery, but now I have a question. Will SW be able to handle this system or should I upgrade to Mamba Max (it's a bit expensive though)?


Thanks!

[Arct1k]

Should be ok but not hearing good things about those motors..

[tomik]

Doesn't matter, it only costs $28 + shipping a couple dollars. Just want to test something and the hong kong people deliver fast :).

How about running SW with 3S lipo and a motor ~3500kV?

[Arct1k]

I would add an UBEC for 3s and maybe an extra cap - Novak HV one works well for 3/4s

[tomik]

Originally Posted by Arct1k

I would add an UBEC for 3s and maybe an extra cap - Novak HV one works well for 3/4s

Forgot to mention. I'm already using CC BEC @ 6,1V.
Are capacitors used to give the needed punch when accelerating?

[Arct1k]

I'm not the guru but believe protects the ESC from voltage ripper under load which can cause spontaneous combustion/failure of ESC.

[tomik]

Mounted SW, BEC and Rx. Some new images: http://tomikulmala.smugmug.com/galle...fYsp#331779442

[tomik]

The motor finally arrived and I threw it in with 1800mAh 20C Lloong-Max 3S pack from Hobbycity just to test the setup before the real 2S battery arrives.

Set the SW to medium and 40% punch control and went out.

This thing flies even with these settings :D. No chance of actually handling the car even at 50% throttle! Insane.

As you might already guess, the battery was quite warm after some 5 minutes of mild bashing around the yard. Motor was warmer, but I don't have an infrared temp gun so I don't know any numbers :(.

[Arct1k]

PS that was voltage ripple - dodgy typing!

PPS glad it is working

Originally Posted by Arct1k

I'm not the guru but believe protects the ESC from voltage ripper under load which can cause spontaneous combustion/failure of ESC.

[tomik]

I just had to take the 1800mAh 20C 3S pack outside again with the setup (16T pinion, btw). After about 10 minutes the car stopped and then I remembered the temps... Darn! The motor was so hot I couldn't even touch it, SW almost the same and battery too very hot.

Went inside and let the system cool down a bit. Connected the battery again and the car moved for a short while and stops again (at this point my guess is the ESC and motor are ok). I connected the battery once more and what does SW say? "Beep-beep" (auto-lipo -setting is selected). Well, my 3S became 2S .

Anyway... The car flies (my standard; my first brushless race car) and therefore I couldn't care less if one $25 1800mAh pack was dead. It was worth it!

Hopefully I learned something today (to buy better equipment and to watch the temperatures) .

[tomik]

Some test drives with datalogger today :). Here you go...

Setup: HN CRT.5, CC SW, CC BEC, KD36-60-07L 3500kV, 16T pinion.

Test #1 with 1800mAh 20C 3S pack from HobbyCity (Lloong max).
Max amps: 91,19A
Watts: 699W
Voltage(t) and Amps(t) -chart from test #1

Test #2 with 6000mAh (100Amps) 2S pack.
Max amps: 115,18A
Watts: 706W
Voltage(t) and Amps(t) -chart from test #2


Then after a little while of running with the 2S pack there was a ~15secs break and then the car died!
- SW keeps blinking all three lights
- CC BEC has no leds whatsoever
- Steering servo doesn't work

To me it seems like CC BEC is dead, but how can it be? It should be able to handle from 4,8V to 25V. Can anyone tell me what could have gone wrong?

EDIT: I measured the output voltage, which is 2,14V. It should be 6,1V :(.

Tomi